Method and apparatus for screening cells or formed bodies with populations expressing selected characteristics utilizing at least one sensing parameter

METHOD AND APPARATUS FOR SCREENING CELLS OR FORMED BODIES WITH POPULATIONS EXPRESSING SELECTED CHARACTERISTICS UTILIZING AT LEAST ONE SENSING PARAMETER

Technical Field

This invention relates generally to a method and apparatus for screening cells or formed bodies for the enumeration of populations which express selected characteristics for research, diagnostic or industrial purposes. More particularly, the invention is directed to an analysis of overlapping populations or subsets thereof, analysis of formed bodies and multipart blood cell or subset population analysis by elimination of populations and/or subsets, utilizing at least a single sensing parameter and microspheres having specific monoclonal antibodies bonded thereto.

Background Art

This invention relates generally to an automated analyzer and methods of using same for screening biological cells or formed bodies for the enumeration of populations which express selected characteristics for research, diagnostic, medical or industrial purposes. More particularly, the automated analyzers and methods embodying the invention enable multiple part classifications of cells and formed bodies, functional phenotyping of cells and formed bodies, typing of leukemic, lymphoma and solid tumor cells, among others, using a unique combination of electronic and optical technology and the specificity of selective biological molecules, such as antibodies, for such screening and selective enumeration of the cells and formed bodies.

Automation of routine complete blood cell (CBC) analysis of human peripheral blood by an automated blood cell counter was successfully achieved by the

COULTER COUNTER Model A of Coulter Electronics, Inc. of Hialeah, Florida. The electronic particle sensing system principle of that instrument is disclosed in U.S. Patent No. 2,656,508 issued October 20, 1953 to Wallace H. Coulter. The use of optical sensing means or lasers, which can be troublesome and expensive are avoided by particle analyzing instrumentation solely operated on this Coulter electronic sensing principle.

This Coulter sensing principle was developed and expanded into more sophisticated instrumentation such as the COULTER COUNTER® Model S types of instruments which enabled CBC parameters, absolute cell counts, platelet count and morphology, red blood cell (RBC) morphology, interpretation of normal and abnormal blood specimens by specific computer programs.

The Coulter electronic particle sensing principle employs an aperture sensing circuit using a direct current (DC) aperture supply. Such particle sensors are simple in structure, extremely rugged and reliable as attested to by the substantially universal acceptance of the COULTER COUNTER© automated analyzer in clinical laboratories in the United States and throughout the rest of the World. An improvement in this basic aperture sensing circuit was disclosed in U.S. Patent No. 3,502,974 issued in 1970 to Wallace Coulter and Walter Hogg. In addition to the standard direct current aperture supply, a high frequency aperture current was applied which enabled the sensing of an additional parameter for classification purposes. The high frequency aperture current produced a signal which is the function of the blood cell's internal conductivity as well as its volume. The signal produced simultaneously by the direct current aperture circuit is a conventional DC amplitude signal which provides an indication primarily of cell volume. The radio frequency amplitude is divided by the direct current pulse amplitude employing a high speed divider circuit to obtain a quotient which is a function of cell volume and internal resistance, conveniently referred to as opacity. This principle is further described in U.S. Patent No. 3,502,973 also issued to Wallace Coulter and Walter Hogg, in 1970. This parameter has applicability in cell classification systems. Either a single or a pair of separate apertures could be utilized for this purpose.

Classification of different populations is accomplished by collating the data of the signal pairs as they are produced; one, a measure of particle volume and the other a measure of cell internal resistivity or opacity. A convenient form of presenting this data is by two-dimensional plots referred to as scatterplots or scattergrams. Such plots are well described in Flow Cytometry and Sorting, page 371; edited by Melamed Melaney, and Medelsohn, 1979, John Wiley & Sons, NY, NY.

FIG. 5A is one example of a data plot of a sample of normal blood. Each dot represents an individual cell. The height above the baseline represents the relative volume of the cell. The distance of the dot to the right of the vertical baseline represents the relative opacity. A plot of normal white blood cells (WBC) (with the red blood cells removed) shows three clusters of dots representing three distinct populations which are a consequence of their intrinsic differences in size and internal composition. If desired, with suitable circuitry, these populations can be enumerated to obtain the numbers of each. The cells are classified on the basis of these inherent differences.

Initial applications of the Coulter electronic particle sensing principle was to perform red blood cell counts and then, more sophisticated determinations of other red blood cell parameters. By removing red blood cells from whole peripheral blood, analysis of the white blood cell populations could be undertaken so long as the red blood cell removal did not significantly impair properties of the remaining white blood cell populations sought to be measured. Red blood cell lysing reagents were developed for this purpose which, though useful and widely applied, were not entirely satisfactory in all respects for subsequent white blood cell determinations.

Previous methods of flow analysis of leukocytes using DC volume alone or light scatter at various angles have shown three clusters of leukocytes corresponding to lymphocytes, monocytes and granulocytes which included the neutrophil, basophil and eosinophil populations. A rough but useful estimation of eosinophil concentration can be made on some samples. The fifth major population is relatively too small for this approach. The eosinophils also have been observed as a distinct cluster using special fluorescence techniques.

These fluorescent techniques were utilized in flow cytometry instruments such as the EPICS® flow cytometer available from the Coulter Corporation. Such instruments employed the principle of cells moving in a columnar stream bounded by a sheath flow such that cells lined up in single file and passed individually through a laser beam. Light scatter and/or fluorescence signals from the cells were then utilized in classifying cell populations. Staining cells with absorptive or fluorescent dyes made additional cell population classifications possible. The development of instrumentation and fluorochromes for automated multiparameter analysis is further described by R. C. Leif, et al. in Clinical Chemistry, Vol. 23, pp. 1492-98 (1977). These developments expanded the number of simultaneous population classifications of leukocytes to four, namely lymphocytes, monocytes, eosinophils and granulocytes (neutrophils and basophils).

A more recent analytical hematology instrument has utilized light scattering techniques together with peroxidase enzyme staining (absorptive dye) of cells to produce a five part leukocyte differential. Moreover, dyes in combination with specific reacting biological molecules, such as monoclonal antibodies, have increased the number of leukocyte classifications possible to include functional subdivisions.

An improved single automated instrument and methods of using the same is disclosed in W088/07199 entitled AUTOMATED ANALYZER AND METHOD FOR SCREENING CELLS OR FORMED BODIES FOR ENUMERATION OF POPULATIONS EXPRESSING SELECTED CHARACTERISTICS. This patent combines the application of electronic sensing aperture principles, the specificity of selected biological molecules for identifying and/or enumerating defined populations of cells or formed bodies and microscopic particle technology. The automated analyzer can be used together with a special lysing reagent and/or antibodies coupled to microscopic microspheres or supports of varying composition.

A second patent , W090/07259 entitled METHOD AND APPARATUS FOR SCREENING CELLS OR FORMED BODIES WITH POPULATIONS EXPRESSING SELECTED CHARACTERISTICS, discloses the screening of direct subsets from whole blood samples or portions thereof.

Selectively attaching microscopic particles makes possible the modification of the parameter(s) responsible for the original location of at least one of the populations. The bulk addition of microscopic particles to selected target populations where this addition affects the measured volume and/or opacity results in shifting the location of the dots representing a population.

Antibodies of known specificity are employed in coating microscopic . particles. This coating gives the particle the capacity to selectively attach to certain cells which express the antigen the antibody is specific for. These coated or tagged cells are a combination of particles and cell which behave like a new entity. Their parameters of opacity, volume, or both opacity and volume may be considered to represent the sum of the effects of both the cell and the particles on the signals obtained. If the characteristics of the components are different, the new entity will move to a new position in accordance with the net effect. The new location, in contrast with the former position of the cell alone, should allow a classification of such new entity or group of new entities. If the particles attached to the cells are magnetic, then, of course, according to current practice, the new entities can be captured by the use of a magnet. If mixed rapidly, unexpected results including complete capture of a population without adversely affecting the properties of the cells under study occur.

Only three distinct populations of cells can be readily identified and enumerated from a blood sample by utilizing their inherent and unique properties of DC volume and opacity parameters heretofore stated. Additional steps such as improved lysing systems, must be taken to enable the detection and enumeration of more populations. Of course, these additional populations represent subpopulations of the three basic ones referred to as lymphocytes, monocytes and granulocytes. The steps performed in accordance with the parent application demonstrate how subpopulations of these basic three populations are obtained.

Employing such simple aperture sensing techniques in combination with two or more biological particles, one can produce a unique and new position of the dot cluster representing a given population. This selective movement of populations on the dot plot or scattergram is reproducible and can be used to classify a population separate from the basic three populations.

The original and inherent combination of DC volume and opacity sensing techniques can be modified through the attachment of microscopic particles to selected individual cells. The selectivity is given the particles by the nature or specificity of the biological molecules, antibodies among others, employed as the coating on their surfaces. A population of cells alone, having no particles on I their surface, may occupy a dot plot position no different from other populations or subpopulations, and, henceforth, not be distinguishable from one another. The addition of particles having a selective attraction to a specific population of cells which one seeks to identify, enumerate, and study is possible using this approach. The selective addition of a sufficient mass of selective particles to a distinct population of interest results in the shifting of that population's dot plot location as a result of the new and unique combination of mass, volume and opacity.

The separation of specific cell populations is accomplished without materially affecting the properties of remaining cell populations. For example, the removal of erythrocytes or red blood cells (RBC's) from whole blood in accordance with this invention permits the measurement of T4 and/or T8 lymphocytes not otherwise possible with heretofore available chemical RBC lysing reagents. Ratios of the number of T4 versus T8 cells have been used to indicate immune deficiencies consistent with severe viral infections including the AIDS virus among others. The presence of specific receptors on the surface of cells can be used to classify a population into subsets, whose enumeration permits the detection of the onset of disease. For example, in the predominant forms of leukemia there is a sharp rise in peripheral blood lymphocytes. If the subpopulation of lymphocytes which is rapidly proliferating bears the Til receptor, the patient is at risk of immune abnormalities.

The method and apparatus embodying the invention can be utilized with a variety of immunological reactions, such as immunological reactions involving reactants and formed bodies or cells. As utilized herein, cells are defined as animal or plant cells, which are identifiable separately or in aggregates. Cells are the least structural aggregate of living matter capable of functioning as an independent unit. For example, human RBC and WBC populations, cancer or other abnormal cells from tissue or from blood samples. Formed bodies are defined as bacteria, viruses and fungi which also can include a substrate. The invention can be utilized in diagnosing, monitoring or treating of patients. The invention specifically can be utilized to eliminate or shift populations to analyze populations or subpopulations which cannot otherwise easily be identified. The cells and formed bodies suitably tagged or labeled reasonably can be expected to be sensed by the method and apparatus of the invention in the same manner as the human blood cell examples. The change in parameter can be sensed without regard to the substrate or lack thereof.

This invention provides a single versatile analyzer and methods of using same which combines a minimum of electronic and/or light particle sensing technology and the specificity of selective biological molecules to enable a major advancement in the field of automated analyzers for clinical laboratory use, and for industrial applications. The detection of multiple leukocyte subpopulations, and their relationship to one another in human peripheral blood is important in medical research and the diagnosis of human diseases. Such data are useful as a screening tool for identifying and classifying diseases, such as leukemia. Abnormal situations identified by implementation of the invention herein provides diagnostically relevant information in areas of study not limited only to detection of leukocyte populations as will be apparent from the specification and drawings hereof.

One of the most valuable features of this invention is that it employs the single rugged Coulter sensing operation. It is stable and does not require the complexity and expense of complex optical systems but can utilize light sensing if desired. The circuitry required for the addition of the RF generator and detector is economical, compact and reliable. A single aperture is all that is required, but the addition of a second or even a third aperture can enable a greater sample throughput rate economically.

Disclosure Of Invention

A method and apparatus for performing screening of cells or formed bodies for enumerating populations to identify selected characteristics or properties expressed by the cells or formed bodies or subsets thereof. Multipart or five part white blood cell differentials, lymphocyte subsets and overlapping determinations can be performed from a whole blood sample or from a sample with the red blood cells and/or populations of the white blood cells removed by elimination of populations and/or subsets thereof.

A whole blood sample or portion thereof can be screened to provide the desired analysis of the WBC populations, again by elimination of populations and/or subsets from the sample.

The RBC population is removed or preremoved from the sample without substantially affecting the characteristic of interest of the WBC population and subset thereof.

At least one WBC population subset is substantially depleted from a sample and then at least the analysis of the population and the population subset with the WBC population depleted thereof are compared to determine at least one characteristic of the WBC population. At least one WBC subset population is subtracted from a sample and then the subtracted sample portion and the original sample portion are analyzed and compared to determine the percentage population of an otherwise obscured WBC population.

Brief Description Of Drawings

The preferred embodiments of this invention will now be described by way of example, with reference to the drawings accompanying this specification in which:

Figs. 1-13 describe the embodiments disclosed in ’<)88/07199 ;

FIG. 1 is a schematic block diagram of one cell population analyzer embodiment of the parent application;

FIG. 2 is a schematic block diagram of a second analyzer embodiment of the parent application;

FIG. 3 is one specific analyzer embodiment of the parent application corresponding to FIGS. I and 2;

FIG. 4 is a schematic block diagram of another analyzer embodiment of the parent application;

FIGS. 5A and 5B are a scattergram of one set of results utilizing a prototype analyzer system similar to that illustrated with respect to FIGS. 2 and 3;

FIG. 6 is a schematic block diagram of a further analyzer embodiment of the parent application;

FIG. 7 is a schematic block diagram of a still further analyzer embodiment of the parent application;

FIGS. 8A and 8B, 9A and 9B, 10A and 10B and 11A and 11B are a scattergram of one set of results utilizing a prototype analyzer system similar to that illustrated with respect to FIGS. 6 and 7;

FIG. 12 is a schematic block diagram of a yet still further analyzer embodiment of the parent application;

FIG. 13 is a scattergram of one set of results utilizing a prototype analyzer system similar to that illustrated with respect to FIG. 12;

Figs. 14-26D describe the embodiments disclosed in the second patent, W090/07259 ;

FIG. 14 is a schematic block diagram of one WBC population subset analyzer embodiment of the parent application;

FIG. 15 is another schematic block diagram of a WBC population subset analyzer embodiment of the parent application;

FIG. 15 is one specific analyzer embodiment of the parent application corresponding to FIGS. 14 and 15;

FIGS. 17A and 17B are a scattergram of one set of results utilizing a prototype analyzer system similar to that illustrated with respect to FIGS. 3 and 16;

FIG. 18A is a scattergram of the L, M and G populations and FIG. 18B is a scattergram of the L, M and B populations utilizing a prototype analyzer system similar to that illustrated with respect to FIG. 15;

FIGS. 19A-D, 20A-D and 21A-D are. scattergrams of the CD4, CD8, CD2 and CD20 subset populations of samples of different patients;

FIG. 22A is a scattergram similar to the scattergram of FIG. 18A, FIG. 22B is a scattergram illustrating shifting of the E and N populations and FIG. 22C is a scattergram illustrating shifting of the. E, N and CD4 populations;

FIGS 23A-D are scattergrams illustrating a direct WBC subset analysis utilizing one microsphere bound to the WBC subset of interest and a second microsphere bound to the first microsphere;

FIGS. 24A-C are scattergrams illustrating the effect of the size of the microsphere utilized in the shifting analysis of the parent application;

FIGS. 25A-D are scattergrams illustrating a simultaneous analysis of two WBC subset populations by the techniques of the parent application;

FIGS. 26A-D are scattergrams of the same populations illustrated on different parameter scattergrams;

FIGURES 27-46 are directed to embodiments of the present invention;

FIG. 27 is a schematic block diagram of one single sensing parameter multipart WBC population subset analyzer embodiment of the invention;

FIG. 28 is one specific analyzer embodiment of the present invention corresponding to FIG. 27;

FIGS. 29A-D are scattergrams of one set of results utilizing a prototype analyzer system and a DC sensing parameter similar to that illustrated with respect to

FIGS. 27 and 28;

FIGS. 30A-D are scattergrams of the same results of FIGS. 29A-D utilizing an RF sensing parameter;

FIGS. 31A-D are scattergrams of a second set of results utilizing the prototype analyzer system and a DC sensing parameter similar to that illustrated with respect to FIGS. 27 and 28.

FIGS. 32A-D are scattergrams of the same results of FIGS. 31A-D utilizing a RF sensing parameter;

FIGS. 33-36 are scattergrams of results illustrating the use of a single light sensitive parameter;

FIG. 37 is a schematic block diagram of a WBC population subset analysis for enhancing small or obscure populations;

FIGS. 38A-E are scattergrams of one set of results obtained utilizing a prototype analyzer system and an RF sensing parameter similar to that illustrated with respect to FIGS. 27 and 37;

FIGS. 39A-E are scattergrams of another set of results obtained utilizing a DC sensing parameter;

94067#

FIGS. 40Ά-Ε are scattergrams of the same set of results utilizing an RF sensing parameter;

FIGS. 41A-E are scattergrams of one set of results obtained utilizing two sensing parameters;

FIGS. 42A-G and 43A-G are scattergrams of results obtained utilizing various sensing parameters on two respective abnormal blood samples;

Mode For Carrying Out The Invention FIGS. 1-13 describe the embodiments of W088/07199;

Referring to FIG. 1, a first embodiment of a cell population analyzing method and apparatus of

W08S/07199 is designated generally by the reference numeral 10. The analyzer 10 includes a biological sample 12 which contains at least a first set of viable biological cells (not illustrated), such as in or from a whole blood sample. The cells of the biological sample 12 are to be involved in a biological reaction in a quantitative and/or qualitative determination or analysis. The sample 12 can include a buffer into which the cells are added.

The sample 12 is combined via a line 14 with at least one reactant 16 via a line 18. The red blood cells (RBC) then are removed from the mixture by a functionally designated RBC removing station 20. The RBC's can be removed from the mixture by the station in a number of ways. The RBC's can be lysed by a lyse in the reactant 16. One such preferential lyse and a quench which can be utilized therewith is disclosed in WO88/07187 . ־־, entitled METHOD AND REAGENT SYSTEM FOR ISOLATION, IDENTIFICATION AND/OR ANALYSIS OF LEUKOCYTES FROM WHOLE BLOOD SAMPLES, incorporated herein by reference. The reactant 16 can be or include a plurality of magnetic microspheres with an antibody specific to the RBC's bound to the microspheres (not illustrated). In this example, the particular red blood cell specific antibody utilized is disclosed in U.S. Patent No. 4,752,563, entitled MONOCLONAL ANTIBODY FOR RECOVERY OF LEUKOCYTES IN HUMAN PERIPHERAL BLOOD AND METHOD OF RECOVERY EMPLOYING SAID MONOCLONAL ANTIBODY, which is incorporated herein by reference. The reactant 16 also can include a buffer in addition to or in place of the sample buffer. The reactant 16 further can be a combination of the preferential RBC lyse and the RBC specific microspheres.

Once the RBC's substantially are removed from the mixture, a portion of the mixture is fed into a white blood cell (WBC) analyzer 22 via a line 24. The WBC analyzer 22 at least counts the number of WBC's in the mixture. The WBC analyzer 22 also can measure one or more volume or opacity parameters of the WBC's. The results from the analyzer 22 are fed to a comparator 26 via a line 28.

A second portion of the RBC deleted mixture is fed to a WBC subset subtracting station 30 via a line 32. The WBC's can be subtracted from the mixture in a number of ways. Microspheres with a monoclonal antibody specific to one of the WBC subsets bound thereto can be added to the mixture. Non-magnetic microspheres can be bound to the WBC's to change or shift the resultant opacity or volume parameters of the cells. Magnetic microspheres also can be bound to the WBC's which then can be removed from the mixture by a magnetic field.

The mixture with the WBC subset population removed or with one or more parameters changed then is fed to a WBC subset analyzer 34 via a line 36. The analyzer 34 can be identical to the analyzer 22. The results of the analyzer 34 are then fed to the comparator 26 via a line 38. The comparator 26 then can compare the WBC results from the analyzer 22 with the modified results from the analyzer 34 to determine at least one characteristic of the selected white blood cell population, such as the number of cells in a particular range.

Referring to FIG. 2, a second embodiment of a cell population analyzing method and apparatus embodying the parent application is designated generally by the reference numeral 40. The analyzer 40 includes a biological sample 42 which again contains at least a first set of viable biological cells (not illustrated), such as in or from a whole blood sample. The cells of the biological sample 42 are to be involved in a biological reaction in a quantitative and/or qualitative determination or analysis. The sample 42 again can include a buffer into which the cells are added.

The sample 42 is combined via a line 44 with at least one reactant 46 via a line 48. In the analyzer 40, the RBC's are removed from the mixture and simultaneously at least one characteristic of at least one WBC subset is changed or shifted by a functionally designated RBC removing and WBC shifting station 50.

As stated above, the RBC's can be removed from the mixture by the station in a number of ways, previously enumerated with respect to the station 20. Simultaneously, in the same mixture portion, the WBC's are bound to, generally non-magnetic, microspheres to change or shift the resultant opacity and/or volume parameters of the cells.

The mixture with the RBC's removed and the WBC subset population shifted then is fed to an analyzer 52 via a line 54. The analyzer 52 can be substantially identical .to the analyzer 22. The analyzer 40 thus provides a fast, direct analysis of at least one characteristic of a selected WBC population or WBC subset.

One specific embodiment of an analyzer instrument embodying WO88/07199 and which can accomplish the analyzing methods of the first and second analyzers 10 and 40, is designated generally by the reference numeral 56 in FIG. 3.

In the instrument 56, only one specific enumeration is illustrated, which can be varied in almost endless detail in accordance with the principles of the parent application. Further, the instrument 56 is shown in generally functional detail and the specific embodiments can be structurally implemented in many known ways.

The instrument 56 includes an aspirator pumping mechanism 58 which is utilized to draw the biological sample of interest, for example the sample 12 or 42 into the instrument 56. The aspirator 58 is coupled via a line 60 to a sampling valve 62, which can be coupled to a sample probe 63. A lyse pump 64 can include the lyse, such as part of the reactant 18 or 46 and is also coupled to the valve 62 via a line 66. The valve 62 and the pump 58 can aspirate the biological sample 12 or 42 along with the lyse via the pump 64 when appropriate.

The reactant mixture or the biological sample itself, then is fed via a discharge line 68 into a mixing apparatus 70. The mixer 70 includes a mixing chamber 72 into which the sample or reactant is fed. At this point the operation of the analyzer 10 and 40 differ and hence will be described separately.

In the case of the analyzer 10, if the RBC's have been lysed by the lyse from the pump 64, then when the reaction is completed a quench or fix is supplied from a station 74 via a line 76. The reaction can be assisted by mixing the lyse and the sample in the chamber 72 as illustrated functionally at 78.

Specific details of an appropriate mixing apparatus 70, which can be utilized herein are disclosed in W088/06918 entitled METHOD AND APPARATUS FOR RAPID MIXING OF SMALL VOLUMES FOR ENHANCING BIOLOGICAL REACTIONS, which is incorporated herein by reference. By utilizing the mixer 70 the reactions are greatly enhanced in speed without significantly damaging the properties of interest of the cells, such as, can occur by raising the reaction temperature. Further, the reactions generally are completed in significantly less than a minute, generally on the order of fifteen seconds or less. This allows a rapid analysis of the automatic high volume analyzer instrument 56.

The quenched reactant with the RBC's removed by the lyse (as from the station 20) then is fed via a line 80 to a holding chamber 82, which in this case will hold a second portion of the mixture. A first portion of the mixture will be fed from the chamber 82 via a line 84 to a WBC analyzer 86 (i.e., analyzer 22). The analyzer 86 can be of many physical types in accordance with the counting and sizing techniques described by Wallace H. Coulter in U.S. Patent

No. 2,656,508 and embodied in the numerous commercial blood cell counters of the assignee, Coulter Electronics, Inc.

The analyzer 86, in general, includes a flow sensor or sensing chamber 88. The chamber 88 includes a transducer 90 which has an aperture 92 therethrough. The chamber 88 includes a first portion 94 which has a first electrode 96 in contact with the fluid therein.

The chamber portion 94 and the electrode 96 communicate through the aperture 92 with a second chamber portion 98 having a second electrode 100 therein.

The electrodes 96 and 100 are coupled via reactive leads 102 and 104 to an RF/DC source and sensing circuit 106. The circuit 106 couples both a DC, or low frequency current or signal, and a high frequency signal between the. electrodes 96 and 100.

The. low frequency signal is utilized to sense the amplitude of a signal pulse caused by a cell passing through the aperture 92. The high frequency signal is utilized to obtain the electrical opacity of the same cell passing through the aperture 92.

The measuring of the electrical opacity of cells was described by Wallace H. Coulter and Walter R. Hogg in U.S. Patent No. 3,502,974 and several patents and publications of the assignee, Coulter Electronics, Inc., since that patent. One specific circuit which can be utilized herein is disclosed in US 4,791,355 entitled PARTICLE ANALYZER FOR MEASURING THE RESISTANCE AND REACTANCE OF A PARTICLE which is incorporated herein by reference.

The signals generated by the circuit 106 from the sensed cells are coupled via a DC signal lead 108 and an RF signal lead 110 to a comparator 112 (like the comparator 26). The comparator 112 can hold the signal generated from the first portion, i.e., those without the WBC subset subtracted, for a comparison with the results from the second portion to be described.

The analyzer 86 can include a sheath flow to focus the cells in the sensor 88, in the well known manner. The sheath flow can be provided by a fluidic system 114, coupled to the sensor 88 by a pair of lines 116 and 118 in a known manner. The sample reaction mixture can be fed into the sensor 88 via an introduction tube 120 and can be fed from the sensor 88 via an exit tube 122 into a waste container 124.

While the first portion of the mixture was being analyzed in the analyzer 86, the second portion is held in the chamber 82, while the mixer 72 is cleaned or flushed via a rinse line 126 and exhausted through a waste line 128. Once the chamber 72 is cleaned, the second portion is fed back into the chamber 72 via a line 130. Like the station 30, the WBC subset now is subtracted by adding the WBC microspheres from a station 132 via a line 134, a valve 136 and a chamber line 138.

The WBC microspheres are mixed with the second portion by the mixing mechanism 78. If the WBC microspheres are non-magnetic, the reaction mixture with the bound WBC microspheres is fed via the line 80, the chamber 82 and the line 84 into the analyzer 86 (i.e., the analyzer 34), wherein the second portion is analyzed like the first portion and the results then are compared in the comparator 112 (i.e., the comparator 26). At least one of the WBC subset cell parameters is changed in the second portion, such as the cell opacity by the WBC subset bound microspheres to provide the changed results which then can be analyzed.

If the WBC microspheres are magnetic, then the WBC subset bound thereto are removed by a magnetic field during and/or after the mixing process by a magnetic field or magnet 140. The field can be provided by electromagnetic means or by the magnet 140 being physically moved with respect to the chamber 72 to capture the magnetically bound WBC subset. The second portion without the bound WBC subset then is fed via the line 80, the chamber 82 and line 84 to the analyzer 86 in the manner previously described to obtain the analysis (like the analyzer 34).

The instrument 56 then is prepared to take the next sample for the next analysis. The probe 63 can be cleaned by a probe rinse mechanism 142 and the lines and chamber 72 and 82 can be flushed in a conventional manner. Each analysis of the succeeding sample mixture is obtained in a rapid and automatic fashion. The period between the analysis of succeeding sample mixtures can be on the order of minutes or less.

In operating the analyzer instrument 56, like the analyzer 40, the reaction mixture with the RBC lyse/reactant 46 and the sample 42 is mixed in the chamber 72 along with non-magnetic WBC microspheres from the station 132, which bind to one of the WBC subsets. The quench 74 is added to the reactive mixture which then is fed via the line 80, the chamber 82 and the line 84 to the WBC analyzer 86 for analysis (i.e., like the analyzer 52).

Alternatively to the utilization of the lyse, in either of the analyzers 10 and 40, the sample 12 or can be fed to the mixer 70 via the valve 62 without any lyse. In this case, the RBC's can be removed magnetically by utilizing the microspheres with the RBC specific antibody bound thereto from an RBC microsphere station 144 and fed to the valve 136 via a line 146 and hence to the chamber 70 via the line 138. Where no lyse is utilized, the bound RBC's are magnetically removed by the magnet 140 after mixing in a manner substantially identical to the magnetically bound WBC's described above.

Further, in a second case to promote the speed of the reaction, a reaction mixture of the sample with both the RBC lyse and with the RBC magnetic beads can be utilized. The reaction mixture is mixed, the lyse is quenched and the bound RBC's are magnetically removed and then the WBC's are analyzed as previously described.

Referring now to FIG. 4, another embodiment of a cell population analyzing method and apparatus embodying the parent application is designated generally by the reference numeral 148. The analyzer 148 includes a biological sample 150 which again contains at least a first set of viable biological cells, such as in or from a whole blood sample. The sample 150 again can include a buffer into which the cells are added.

The sample 150 is combined via a line 152 with at least one reactant 154 via a line 156. The RBC's then are removed as above described by a functionally designated RBC removing station 158. The reaction mixture with the RBC's removed is fed via a line 160 into a WBC analyzer 162. The results from the analyzer 162 are fed to a comparator 164 via a line 166, providing a three-part WBC differential with results for monocytes (M), lymphocytes (L) and granulocytes (G).

The mixture then is fed to a neutrophil (N) functionally designated removal station 168 via a line 170. The N's can be removed from the mixture by shifting or changing one parameter, such as opacity, or by magnetic removal, both as described above. In this example, the particular N specific antibody utilized is disclosed i_n W088/04320 MONOCLONAL

ANTIBODY SPECIFIC TO NEUTROPHILS.

The mixture with the N's removed or shifted then is fed to another WBC analyzer 172 via a line 174. The results of the analyzer 172 are fed to the comparator 164 via a line 176. The results of the analyzer 172 are utilized to obtain a four-part WBC differential with results again for M's and L's, but now in addition since the N's are shifted or removed results for eosinophils (E) and basophils (B) are obtained. The two analytical results from the analyzers 162 and 172 then can be compared by the comparator 164 to form a five-part WBC differential. Specifically, subtracting the number of B's and E's from the number of G's results in the number of the removed N's.

Referring now to FIGS. 5A and 5B, two sets of scattergram results are illustrated obtained from a whole blood sample utilizing a prototype analyzing method similar to the analyzer 148. The biological sample 150 was a 20 microliter sample of whole blood which was combined with 40 microliters of the I magnetic microspheres with the RBC specific antibody bound thereto combined with 140 microliters of buffer solution to form the reactant 154. The reaction mixture was mixed for 15 seconds and placed in a magnetic field for 10 seconds in the station 158.

The mixture with the RBC's removed was analyzed by the analyzer 162 as illustrated in the scattergram of FIG. 5A resulting in counts of L's of 45.6 (1), M's of 5.6 (2) and G's of 48.7 (3).

The mixture then is combined in the station 168 with 10 microliters of magnetic microspheres with the N specific antibody bound thereto. The mixture is mixed 30 seconds and then placed in a magnetic field for 10 seconds. The mixture with the N's then removed was fed to the analyzer 176 which resulted in the scattergram of FIG. 5B resulting in counts of L's of 81.0 (1), M's of 0.6 (2), E's of 11.0 (3) and B's of 1.8 (4). The comparator 164 then provides the five-part WBC differential of counts of 45.6 L's,

5.6 M's, 41.6 N's, 6.0 E's and 1.2 B's. This corresponds to a standard microscopic five-part WBC differential utilizing Wright stain on the sample on a slide resulting in counts of 44.0 L's, 3.4 M's, 45.0 N's, 6.1 E's and 0.4 B's.

FIG. 6 illustrates a further embodiment of a cell population analyzing method and apparatus embodying the parent application, designated generally by the reference numeral 178. The analyzer 178 includes a biological sample 180 which again contains at least a first set of viable biological cells and also can include a buffer.

The sample 180 is combined via a line 182 with a reactant 184 via a line 186. Functionally illustrated, a first portion of the mixture is fed via a line 188 to a functionally designated RBC and N removing station 190. The RBC's and N's are removed or shifted as described before and the first portion is fed via a line 192 to a WBC analyzer 194.

This provides a result from the analyzer 194 which is fed via a line 196 to a comparator 198. The results includes the above-referenced four-part differential including M's, L's, E's and B's.

At the same time, a second portion of the mixture of the sample 180 and the reactant 184 is fed via a line 200 to a functionally designated RBC removal station 202. The mixture with the RBC's removed is fed via a line 204 to another WBC analyzer 206. The results of the analyzer 206 are fed to the comparator 198 ₍via a line 208. The results of the analyzer 206 directly include the above-referenced three-part WBC differential including M's, L's and G's. the results of the analyzers 194 and 206 then are compared by the comparator 198 to provide the five-part WBC differential.

A specific analyzing instrument embodiment incorporating the method and apparatus of the analyzer 178 is designated generally by the reference numeral 210 in FIG. 7. Again, only one specific hardware enumeration has been illustrated, but like the analyzing instrument 56, the analyzing instrument 210 can be implemented in numerous configurations.

The instrument 210 includes an aspirator purging mechanism 212 which is coupled to a sampling valve 214 via a line 216. The valve 214 can include a sample probe 218 to aspirate the biological sample of interest, such as the sample 180. A diluent delivery pump 220 is coupled to the valve 214 via a line 222 to provide a diluent for the sample, such as a whole blood sample, when desired. A first portion of the mixture then is coupled via a line 224 and a line 226 to a first mixing apparatus 228. At the same time, a second portion of the mixture is fed via the line 224 and a line 230 to a second mixing apparatus 232.

The mixer 228 (comparable to the station 190) is substantially identical to the mixer 232 (comparable to the station 202) and will be described first. The mixer 228 includes a mixing chamber 234 into which the first mixture portion is fed. The mixer 228 includes all of the various options above described and can include a lyse input line 236 for the RBC lyse if desired.

If the lyse is utilized, after mixing as illustrated functionally at 238, then the quench is added via a quench line 240. At the same time, the N's are being removed by the addition of the appropriate magnetic or non-magnetic microspheres with the N specific antibody bound thereto from a source of microspheres 242 fed to the chamber 234 via a line 244. If magnetic microspheres are utilized for the N's or the RBC's, then a magnet 246 or magnetic field is utilized to remove the magnetically bound cells.

The mixed and quenched (where necessary) mixture then is fed via a line 248 through a valve 250 and a line 252 to a WBC analyzer 254 (i.e., analyzer 194). The analyzer 254 is the same as the analyzer 86 and will not be described again in such detail. Again, the analyzer 254 includes a sensing chamber 256 with an aperture 258 therein through which the mixture and cells pass. A sheath flow fluidic system 260 can be coupled to the chamber 256. The signals generated by the cells are detected by an RF/DC source and sensing circuit 262 whose outputs are fed to a comparator 264, as previously described.

Concurrently, the second mixture portion is fed into a mixing chamber 266. In the second portion, only the RBC's are removed (i.e., like the station 202) and the RBC's can be removed by the RBC lyse fed into the chamber 266 via a line 268. The lyse is mixed with the sample and then a quench is added via a quench line 270. Alternatively the RBC's can be removed by magnetic microspheres having the RBC specific antibody bound thereto from a microsphere source 272 fed into the chamber 266 via a line 274. The microspheres are mixed, functionally at 276, and then the magnetically bound RBC microspheres are removed by a magnet 278.

The RBC removed mixture then is fed via a line 280 to the valve 250 and via the line 252 to the analyzer 254 to obtain the above-mentioned results. The mixers 228 and 232 include appropriate respective rinse lines 282 and 284 and waste lines 286 and 288 and a probe rinse 290 to cleanse the instrument 210 prior to aspirating the next sample or sample for analyzing.

FIGS. 8A and 8B illustrate scattergram results obtained from a whole blood sample utilizing an analyzing method similar to the analyzer 178. In this example, 20 microliters of whole blood form the sample 180, while 40 microliters of magnetic microspheres with the RBC specific antibody bound thereto combined with 140 microliters of buffer solution form the reactant 184. A portion of the mixture is mixed for 20 seconds in the station 202 and then placed in a magnetic field for 10 seconds. The RBC removed mixture then is analyzed in the analyzer 206 resulting in the scattergram of FIG. 8A which provides a count of L's 29.4 (1), M's 8.1 (2) and G's 62.4 (3).

At the same time, another portion of the same mixture is combined with 10 microliters of magnetic microspheres with the N specific antibody bound thereto to remove the RBC's and N's in the station 190. The mixture is mixed for 30 seconds, then placed in a magnetic field for 10 seconds. The mixture with the N's and RBC's removed then is analyzed by the analyzer 194 resulting in the scattergram of FIG. 8B which provides a count of L's 73.5 (1), M's 21.7 (2), E's 3.4 (3) and B's 1.4 (4). The two counts are compared in the comparator 198, resulting in a five-part WBC differential count of L's 29.4, M's 8.0, N's 60.8, E's 1.2 and B's 0.6. A microscope comparison again was made resulting in counts of L's 29.4, M's 5.0, N's 65.0, E's 1.0 and B's of less than 1.0.

FIGS. 9A and 9B show scattergram results of a five-part WBC differential example similar to that of FIGS. 8A and 8B. A 20 microliter sample of whole blood was analyzed in the same steps described with respect to FIGS. 8A and 8B resulting in the scattergram of FIG. 9A providing a count of L's 35.4 (1), M's 14.6 (2) and G's 50.0 (3). The scattergram of FIG. 9B provides a count of L's 66.4 (1), M's 25.0 (2), E's 6.6 (3) and B's 2.0 (4). The resulting five-part WBC differential results in counts of 35.4 L's, 14.6 M's,

45.5 N's, 3.5 E's and 1.1 B's was compared to a microscope count of 36 L's, 11 M's, 49 N's, 3 E's and 1 B.

FIGS. 10A and 10B show scattergram results of a five-part WBC differential again similar to that of FIGS. 8A, 8B and 9A, 9B, however, in this example, lyse was utilized. In this example, 20 microliters of whole blood was combined with 80 microliters of buffer and 240 microliters of the RBC preferential lyse above referenced. The mixture is mixed for 6 seconds and then a quench is added. The time period is significant, because the lyse left unquenched for a period of time greater than about 10 seconds will start to affect the significant properties of the WBC's. The mixture with the RBC's removed is analyzed to provide the scattergram of FIG. 10A resulting in counts of L's 25.7 (1), M's 9.6 (2) and G's 65.0 (3).

A second portion of the mixture including a second 20 microliter sample of the whole blood is combined with 120 microliters of buffer and 10 microliters of magnetic microspheres with the N specific antibody bound thereto and mixed for 30 seconds and then placed in a magnetic field for 10 seconds. The RBC preferential lyse then is added to the N removed mixture which then is mixed for 6 seconds before it is quenched. The resulting scattergram FIG. 10B results in percentage counts of L's 74.6 (1), M's 21.6 (2), E's 2.9 (3) and B's 0.8 (4). The resulting five-part WBC differential results in percentage counts of L'S 25.6, M'S 9.6, N'S 63.5, E׳S 1.06 and B'S 0.3. Again a microscope comparison resulted in counts of L's 29.4, M's 5.0, N's 65.0, E's 1.0 and B's of less than 1.

Another example of scattergram results of a five-part WBC differential similar to that of FIGS. 10A and 10B is illustrated in FIGS. 11A and 11B. A sample of whole blood had two samples simultaneously analyzed in the same steps described with a respect to FIGS. 10A and 10B. The scattergram

<td> of</td><td> FIG. 11A provides</td><td> a</td><td> count</td><td> of</td><td> L's 31.9 (1),</td>

<td> M'S</td><td colspan="2"> 17.6 (2) and G'S 50.4</td><td> (3).</td><td> The</td><td> scattergram of</td>

<td> FIG.</td><td> 11B provides a</td><td colspan="2"> count</td><td> of</td><td> L's 67.1 (1),</td>

<td> M'S</td><td> 24.1 (2), E's 7.6</td><td> (3)</td><td> and</td><td> B's</td><td> 1.2 (4). The</td>

resulting five-part WBC differential results in counts of 31.9 L's, 11.4 M's, 46.0 N's, 3.6 E's and 0.7 B's as compared to a microscope count of 36 L's,

M's, 49 N's, 3 E's and 1 B's.

A yet still further embodiment of a cell population analyzing method and apparatus embodying the parent application is designated generally by the reference numeral 292 in FIG. 12. The analyzer 292 includes a biological sample 294, again including at least a first set of viable biological cells and including a buffer if desired.

The sample 294 is combined via a line 296 with at least one reactant 298 via a line 300. In the analyzer 292, the RBC's are removed and the N's are shifted sequentially or simultaneously in a functionally designated station 302. The RBC remove function is designated 304 and the Ν move or shift portion is designated 306 to indicate that the functions can be performed simultaneously or sequentially. The RBC's can be removed magnetically or with lyse or with a combination of the two as previously described. The N's are removed or shifted by adding microspheres having an N specific antibody bound thereto to the mixture.

Once the RBC's are removed and the N's are moved or shifted, then the resulting mixture is fed via a line 308 to an analyzer 310. In this case, the N's are shifted sufficiently from the patterns of the E's and B's that a five-part WBC differential of M's, L's, E's, B's and N's is directly obtained. The functions of the analyzer 292 can be performed on either of the instruments 56 and 210 or minor variations thereof.

The scattergram results of one example of a direct five-part WBC differential in accordance with the analyzer 292 is illustrated in FIG. 13. In this example, the biological sample 294 is 20 microliters of a whole blood sample and the reactant 298 is 10 microliters of non-magnetic microspheres with the N specific antibody bound thereto combined with 100 microliters of buffer and mixed in the substation 306 for 30 seconds. The RBC preferential lyse, 10 microliters thereof, then is added to the mixture which is mixed in the substation 304 for 6 seconds after which the quench is added. The RBC removed and N shifted mixture then is analyzed by the analyzer 310 resulting in the scattergram of FIG. 13 which provides a direct count of 29.6 L's, 13.6 M's,

52.2 N's, 3.4 E's and 1.06 B's as compared to a microscope determination of 35 L's, 5 M's, 56 N's, 4 E's and no B's. In this particular example, the whole blood sample was also analyzed on a general cell counting instrument of Coulter Electronics, Inc., which resulted in 29 L's, 11.1 M's and 59.9 G's (N's, E's and B's).

Referring now to FIGS. 1-26D, the embodiments of the second parent application Serial No. 285,856 are illustrated.

Referring to FIG. 14, a first embodiment of a WBC population subset analyzer method and apparatus of the second parent application is designated generally by the reference numeral 320. The analyzer 320 includes a biological sample 322, which contains at least a first set of viable biological cells (not illustrated), including at least one white blood cell population having at least one definable subset, such as in or from a whole blood sample. As utilized herein, WBC subsets are subsets of a WBC population to which specific monoclonal antibodies can be bound. A nomenclature now has been defined for the monoclonal antibodies by the World Health Organization and the International Immunology Society. The monoclonal antibodies are defined by a cluster of differentiation (CD) nomenclature which defines a particular specificity for a cell or group of cells and the monoclonal antibodies specific for that CD group. For example purposes only, four CD groups have been utilized in the following examples, CD4, CD8, CD2 and CD20. The CD nomenclature, specificity and some commercial sources of monoclonal antibodies are illustrated in Table I.

TABLE I

<td> Cluster of Differentiation</td><td> Antibody . (Commercial Source)־ Specificity</td>

<td> CD2(gp 50)^a</td><td> Til (Coulter) E Rossette OKT11 (Ortho);Leu5 (BD) Receptor cl</td>

<td> CD4(gp 56) T</td><td> T4 (Coulter) Helper/inducer OKT4 (Ortho);Leu3_a (BD) 81 a</td>

<td> CD8(gp 32-33)</td><td> T8 (Coulter) Cytotoxic/ OKT8 (Ortho);Leu2 (BD) Suppressor T 3</td>

<td> CD20(gp 35)</td><td> Bl (Coulter) All B cells ex- Leu 16 (BD) cept for plasma cells, B cell</td>

tumors, except for myeloma, some non-T ALL cells ^a gp - glycoprotein, molecular weight in kilodaltons

Coulter - Coulter Immunology Division of Coulter Corporation (Hialeah, Florida)

BD - Becton-Dickinson Immunocytometry Systems

Ortho - Ortho Diagnostic Systems (Raritan, New Jersey)

The cells of the biological sample 322 are to be involved in a biological reaction in a quantitative and/or qualitative determination or analysis. The sample 322 can include a buffer into which the cells are added.

The sample 322 is combined via a line 324 with at least one reactant 326 via a line 328. In the analyzer 320, the RBC's are removed from the mixture and simultaneously or sequentially at least one characteristic of at least one WBC subset is changed or shifted by a functionally designated RBC removing and WBC subset shifting station 330. As stated in the first parent application, the RBC's can be removed from the mixture by the station 330 in a number of ways, such as enumerated with respect to the station 20. Simultaneously or sequentially, in the same mixture portion, at least one WBC subset is bound to WBC microspheres having monoclonal antibodies specific to the subset thereon to modify (change or shift) the resultant opacity and/or volume parameters of the cells.

The mixture with the RBC's removed and the WBC subset population shifted, then is fed to an analyzer 332 via a line 34. The analyzer 332 can be substantially identical to the analyzer 22. The WBC subset of interest generally is related as a percentage of the WBC population of interest. The analyzer 320 thus provides a fast direct analysis of at least one characteristic of a selected subset of a WBC population. The analyzer 320 can be utilized where the shifted WBC subset is not obscured by other more numerous cells, or where the number of the shifted cells of the WBC subset is a sufficient percentage as to be identifiable, even though obscured.

Referring to FIG. 15, a second embodiment of a WBC population subset analyzing method and apparatus of the second parent application is designated generally by the reference numeral 340. The analyzer 340 includes a biological sample, which contains at least a first set of viable biological cells (not illustrated), including at least one white blood cell population having at least one subset, such as in or from a whole blood sample. The cells of the biological sample 342 again are to be involved in a biological reaction in a quantitative and/or qualitative determination or analysis. The sample 342 can include a buffer into which the cells are added.

The sample 342 is combined via a line 344 with at least one reactant 346 via a line 348. In the analyzer 340, the RBC's are removed from the mixture and simultaneously or sequentially at least one characteristic of at least one WBC subset is changed or shifted by a functionally designated RBC removing and WBC subset shifting station 350. As previously stated, the RBC's can be removed from the mixture by the station 350 in a number of ways, such as enumerated with respect to the station 20. Again, simultaneously or sequentially, in the same mixture portion, at least one WBC subset is bound to microspheres to modify (change or shift) the resultant opacity and/or volume parameters of the cells.

At the same time or sequentially, at least one WBC population or subset is removed from the mixture. The WBC population or subset is removed so that the WBC subset of interest is not obscured by the population. This preferably is accomplished by magnetically removing the WBC population after they are bound to magnetic microspheres which include a monoclonal antibody bound thereto which is specific to the WBC population.

The mixture with the RBC's and the WBC population removed and the WBC subset populations shifted then is fed to an analyzer 352 via a line 354. The analyzer 352 again can be substantially identical to the analyzer 22.

One specific embodiment of an analyzer instrument embodying the second parent application and which can accomplish the analyzing methods of the first and second analyzers 320 and 340, is designated generally by the reference numeral 360 in FIG. 16.

In the instrument 360, like the instrument 56, only one specific enumeration is illustrated, which can be varied in almost endless detail in accordance with the principles of the first parent application. Further, the instrument 360 is shown in generally functional detail and the specific embodiments can be structurally implemented in many known ways.

The instrument 360 includes an aspirator pumping mechanism 362 which is utilized to draw the biological sample of interest, for example the sample 322 or 342 into the instrument 360. The aspirator 362 is coupled via a line 364 to a sampling valve 366 which can be coupled to a sample probe 368. A lyse pump 370 can include the lyse, such as part of the reactant 326 or 346 and is also coupled to the valve 366 via a line 372. The valve 366 and the pump 362 can aspirate the biological sample 322 or 342 along with the lyse via the pump 370 when appropriate. Preferably, the biological sample 322 or 342 is added separately from the lyse.

The reactant mixture or the biological sample itself, then is fed via a discharge line 374 into a mixing apparatus 376. The mixer 376 includes a mixing chamber 378 into which the sample or reactant is fed. The analyzers 320 and 340 differ only slightly in operation and hence will be described together.

In operation, if the RBC's have been lysed by the lyse from the pump 370, then when the reaction is completed a quench or fix is supplied from a station 380 via a line 382. The RBC removal reaction then is completed. The reaction can be assisted by mixing the lyse and the sample in the chamber 378 as illustrated functionally at 384.

Either before, after or concurrently with the removal of the RBC's the WBC's are shifted and in the case of the analyzer 340, one WBC population or subset also is removed. The WBC subset is shifted by adding the specific WBC microspheres from a station 386 via a line 388, a valve 390 and a chamber line 392. The WBC microspheres are mixed with the mixture or the sample by the mixing mechanism 384.

The details of an appropriate mixing apparatus 376 can be substantially identical to the mixing apparatus

70. By utilizing the mixer 376 the reactions are greatly enhanced in speed without significantly damaging the properties of interest of the cells, such as, can occur by raising the reaction temperature. Further, the reactions generally are completed in significantly less than a few minutes and generally can be on the order of two minutes or less. This allows a rapid analysis of the automatic high volume analyzer instrument 360.

In the analyzer 320, the quenched reactant with the RBC's removed by the lyse (as from the station 20) and the modified WBC subset then is fed via a line 394 to a WBC analyzer 396 (i.e., analyzer 332). The analyzer 396 can be of many physical types in accordance with the counting and sizing techniques described by Wallace H. Coulter in U.S. Patent No. 2,656,508 and embodied in the numerous commercial blood cell counters of the assignee, Coulter Electronics, Inc.

As previously described, the analyzer 396, in general, includes a flow sensor or sensing chamber 398. The chamber 398 includes a transducer 400 which has an aperture 402 therethrough. The chamber 398 includes a first portion 404 which has a first electrode 406 in contact with the fluid therein.

The chamber portion 404 and the electrode 406 communicate through the aperture 402 with a second chamber portion 408 having a second electrode 410 therein. The electrodes 406 and 410 are coupled via reactive leads 412 and 414 to an RF/DC source and sensing circuit 416. The circuit 416 couples both a DC, or low frequency current or signal, and a high frequency signal between the electrodes 406 and 410.

The low frequency signal is utilized to sense the amplitude of a signal pulse caused by a cell passing through the aperture 402. The high frequency signal is utilized to obtain the electrical opacity of the same cell passing through the aperture 402.

The measuring of the electrical opacity of cells was described by Wallace H. Coulter and Walter R. Hoff in U.S. Patent No. 3,502,974 and several patents and publications of the assignee, Coulter Electronics, Inc., since that patent. One specific circuit which can be utilized herein is disclosed in U.S. Serial No. 921,654, incorporated herein by reference.

The signals generated by the circuit 416 from the sensed cells are coupled via a DC signal lead 418 and an RF signal lead 420 to a comparator 422 (like the comparator 26).

The analyzer 396 can include a sheath flow to focus the cells in the sensor 398, in the well known manner. The sheath flow can be provided by a fluidic system 424, coupled to the sensor 398 by a pair of lines 426 and 428 in a known manner. The sample reaction mixture can be fed into the sensor 398 via an introduction tube 430 and can be fed from the sensor 398 via an exit tube 432 into a waste container 434.

Following each operation, the mixer 378 is cleaned or flushed via a rinse line 436 and exhausted through a waste line 438. Once the chamber 378 is cleaned, another sample or sample portion can be fed into the instrument 360.

In the analyzer 340, the operation is the same as the analyzer 320 with the addition of magnetic white blood cell population or subset microspheres. The WBC subset bound thereto then are removed by a magnetic field during and/or after the mixing process by a magnetic field or magnet 440. The field can be provided by electromagnetic means or by the magnet 440 being physically moved with respect to the chamber 378 to capture the magnetically bound WBC subset. The mixture without the bound WBC subset then is fed via the line 394 to the analyzer 396 in the manner previously described to obtain the analysis (like the analyzer 320).

The instrument 360 then is prepared to take the next sample for the next analysis. The probe 368 can be cleaned by a probe rinse mechanism 442 and the lines and chamber 378 can be flushed in a conventional manner. Each analysis of the succeeding sample mixture is obtained in a rapid and automatic fashion. The period between the analysis of succeeding sample mixtures can be on the order of five minutes or less.

Alternatively to the utilization of the lyse, in either of the analyzers 320 and 340, the sample 322 or 342 can be fed to the mixer 376 via the valve 366 without any lyse. In this case the RBC's can be removed magnetically by utilizing microspheres with the RBC specific antibody bound thereto from an RBC microsphere station 444 and fed to the valve 390 via a line 446 and hence to the chamber 376 via the line 392. Where no lyse is utilized, the bound RBC's also are magnetically removed by the magnet 440 after mixing in a manner substantially identical to the magnetically bound WBC's described above.

Further, in a second case to promote the speed or efficiency of the reaction, a reaction mixture of the sample with both the RBC lyse and with the RBC magnetic beads can be utilized. The reaction mixture is mixed, the lyse is quenched and the bound RBC's are magnetically removed and then the WBC's are analyzed as previously described.

Referring now to FIGS. 17A and 17B, two sets of results depicted in scattergrams obtained from a whole blood sample utilizing a prototype analyzer similar to the instrument 360 are illustrated. Two WBC populations are removed and the T_o subset is directly o analyzed. The T_ subset is the cells or formed bodies o which have the receptor or antigen to which the T_ o specific antibody binds to. In the Figures, these are designated as T_Q⁺. The cells or formed bodies which o do not have the receptor or antigen to which the T_oo specific antibody binds to are designated as T_ . In o these examples, the biological medium 342 was a 20 microliter sample of whole blood utilized with the mixer 376. In both FIGS. 17A and 17B, the 20 microliter sample of whole blood, medium 342, was combined with 40 microliters of magnetic microspheres with the RBC specific antibody bound thereto, combined with 120 microliters of buffer solution and 10 microliters of magnetic microspheres with an N and E specific antibody bound thereto, combined with 30 microliters of buffer solution which together form the reactant 346. One such exemplary N and E specific antibody is disclosed in U.S. Serial No. 068,618, entitled MONOCLONAL ANTIBODY SPECIFIC TO A COMMON DETERMINANT SITE OF NEUTROPHILS AND EOSINOPHILS. filed June 3, 1987, which is incorporated herein by reference.

The magnetic microspheres can be of any suitable type and in the example are polystyrene magnetic microspheres of 0.7 micron diameter, with a weight to volume of 10% solids, sold by Seradyn, Inc. of Indianapolis, Indiana. The reaction mixture then was mixed in the mixer 376 for 10 seconds, placed in the magnetic field of the magnet 440 for 15 seconds and then the resulting mixture with the RBC's, E's and N's removed was analyzed in the analyzer 396. The resulting scattergram A is illustrated in FIG. 17A.

The scattergram of FIG. 17B results from the same procedure with the addition of 12.5 microliters of non-magnetic microspheres with a T_o specific antibody o bound thereto combined with 12.5 microliters of buffer solution to form the reactant 346. The T_o specific o antibody is sold under the Trademark COULTER CLONE@ by Coulter Immunology Division of Coulter Corporation. The non-magnetic microspheres again can be of any suitable type and in the examples are surfactant free sulfated polystyrene latex microspheres of 1.78 micron diameter with a weight to volume of 8% solids, sold as IDC microspheres by Interfacial Dynamics of Portland, Oregon.

The addition of the T_o microspheres shifts the o bound CD8 cells to an area B where they separately can be identified and counted as seen by comparing the scattergram of FIGS. 17A and 17B. In FIG. 17A the CD8 cells are hidden by the remaining WBC's. The N's and E's are removed from the scattergrams or they would obscure the identification of the shifted CD8 cells in FIG. 17B. FIG. 17A illustrates the removal of the N's and E's, while FIG. 17B then clearly illustrates the shift of the CDS bound cells from area A to area B. The buffer solution can be phosphate buffered saline sold by Sigma Chemical Company of St. Louis, Missouri.

FIG. 18A further illustrates the normal scattergram or 3 parameter histogram positioning of the M, L and G cell populations from the analyzer 352. Without removal of the G's, as seen in FIG. 17B, the area B of the shifted WBC subset would be obscured by the G's, which are far more numerous in number. FIG. 18B is a scattergram illustrating the WBC populations M, L and B remaining after removal of the E's and N's. Although the B's still may partially obscure the area of interest, .their percentage number of the WBC populations is of a small enough order to not substantially affect the desired calculation of the subset, percentage. However, the B's contribution can be subtracted from the subset percentage if so desired.

Referring now to FIGS. 19A-D, 20A-D and 21A-D, the direct subset analysis of the CD2, CD4, CD8 and CD20 WBC subset populations of respective samples from three different patients is illustrated. In the case of each subset population, 28 microliters of a whole blood sample was combined with 20 microliters of magnetic microspheres (2.5% weight per volume solution) with the N and E specific antibody bound thereto. In addition, non-magnetic microspheres with the respective monoclonal antibody for the respective WBC subset are also combined with the sample. The respective amounts of T₄, Τθ, T^^ or B^ coated microspheres are 40 microliters each. (1% weight per volume solution for each one). Each respective total mixture, i.e., N and E microspheres with T_, for o example, is combined with a buffer solution of phosphate buffered saline, 1% bovine serum albumin, pH of 7.2 to 7.4 for a total volume of 150 microliters. Each respective mixture is mixed in the chamber 378 by the mixer 376 for two minutes and then placed in the magnetic field 440 for one minute. In these examples, the RBC's are removed sequentially utilizing the lyse above referred to. The WBC microspheres are first added, then the RBC's are removed by lysing with 300 microliters of lyse, such as Erythrolyse lytic reagent sold by Coulter Electronics, such as from the lyse source 370. The mixture then is quenched with 120 microliters of quench, such as Stabilyse, a leukocyte preservative also sold by Coulter Electronics, from the source 380 and then fed to the analyzer 396 for analysis.

The right-hand block (1) in each scattergram represents the respective WBC subset population of interest. The blocks 1, 2, 3, etc. illustrated in the Figures are visually or automatically fit around the WBC population or subset of interest.

The results were compared utilizing conventional flow cytometry and gave the following comparative results in percentages for the three samples by the method of the invention (SHIFT) vs. flow cytometry (CYT).

T (Fig. 19A) T (Fig. 19B) T (Fig. 19C) B (Fig. 19D) ⁴Shift CYT ”Shift CYT ¹¹Shift CYT ¹Shift CYT

<td> Patient Sample 1</td><td> 51</td><td> 52</td><td> 18</td><td> 22</td><td> 82</td><td> 76</td><td> 15</td><td> ע</td>

<td></td><td> T (Fig. ⁴Shift</td><td> 20A) CYT</td><td> T (Fig. ⁰Shift</td><td> 20B) CYT</td><td> T (Fig. ^x Shift</td><td> 20C) CYT</td><td> B (Fig. Shift</td><td> 20D) CYT</td>

<td> Patient Sample 2 5</td><td> 53</td><td> 54</td><td> 32</td><td> 29</td><td> 89</td><td> 83</td><td> 6.5</td><td> 7-</td>

<td></td><td> T (Fig. ^Shift</td><td> 21A) CYT</td><td> T (Fig. Shift</td><td> 21B) CYT</td><td> T (Fig. Shift</td><td> 21C) CYT</td><td> B (Fig. Shift</td><td> 21D) CYT</td>

<td> Patient Sample 3</td><td> 46</td><td> 46</td><td> 24</td><td> 18</td><td> 86</td><td> 81</td><td> 11</td><td> 10</td>

FIG. 22A also illustrates the normal scattergram or 3 parameter positioning of the M, L and G cell populations from the analyzer 352. Without removal of the N's and E's, the CD4 cell population would be obscured. By shifting the N's and E's with the N and E specific monoclonal antibody microspheres to an area or block 1 illustrated in FIG. 22B, the CD4 population can be shifted and viewed in the block or area 2. This area would have been obscured by the N's and E's as seen in FIG. 22A. In this example for FIG. 22C, 28 microliters of a whole blood sample were combined with 50 microliters of 2.2 micron microspheres with the N and E specific monoclonal antibody bound thereto and 50 microliters of microspheres with T₄ specific monoclonal antibody bound thereto and 22 microliters of diluent. FIG. 22B was the same without the T^ microspheres and with 72 microliters of diluent and FIG. 22A was the same without any microspheres and 122 microliters of diluent.

Referring to FIGS. 23A-D, direct WBC analysis utilizing a plurality of microspheres bound to the WBC subset of interest is illustrated. FIGS. 23A and 23B respectively illustrate scattergrams of only the L population with the T₄ WBC subset and the WBC subset each shifted with 0.8 micron non-magnetic microspheres. The shift is insufficient to differentiate the WBC subset population in FIGS. 23A and 23B. FIGS. 23C and 23D respectively illustrate scattergrams of only the L population with the T₄WBC subset and the T^ WBC subset shifted by being bound to both a 0.8 micron and a 2.2 micron microsphere. The 2.2 micron microsphere is bound to the 0,8 micron microsphere by having Goat anti-mouse IgG antibody bound thereto, which binds to the T₄ or T^^ antibody bound to the 0.8 micron microsphere.

The effect of the size of the non-magnetic microsphere bound to the WBC subset of interest is illustrated in FIGS. 24A-C. In this example, a 28 microliter sample of whole blood was combined with 10 microliters of magnetic microspheres having the N and E specific antibody bound thereto (2.5% weight per volume solution) and 40 microliters of non-magnetic microspheres having the T_ specific antibody bound o thereto (1% weight per volume solution). The T_oo microspheres were of two different sizes to illustrate the difference in the shift on the scattergram. A buffer solution again was added to form a mixture volume of 150 microliters. The mixture was mixed for 2 minutes and placed in the magnetic field for 1 minute. The resultant N and E removed mixture then was lysed to remove the RBC and then analyzed. FIG. 24A illustrates a control WBC subset without a microsphere attached thereto, a T_ o WBC subset with a 2.2 micron non-magnetic microsphere bound thereto and a T_ WBC subset with a 3.0 micron o non-magnetic microsphere bound thereto. The width and height illustrate the standard deviation of the detected signal. FIG. 24B is a scattergram illustrating the T_o WBC subset shift with the 3.0 o micron microspheres bound thereto, while FIG. 24C is a scattergram illustrating the T_o WBC subset shift o with the 2.2 micron microspheres bound thereto. The analyzed percentage of the T_ WBC subset for the o different microspheres were respectively, 20.9 and 19.3. The larger microsphere clearly generated a more distinct scattergram pattern as illustrated by FIG. 24B.

Referring now to FIGS. 25A-D, the simultaneous direct analysis of two WBC subset populations is illustrated in accordance with the second parent application. In this example, 28 microliters of a whole blood sample was combined with 10 microliters of magnetic microspheres having the N and E specific antibody bound thereto, 52 microliters of buffer solution and 40 microliters of non-magnetic 3.0 micron microspheres with the T_ specific antibody o bound thereto and mixed for 2 minutes. The mixture then was placed in the magnetic field for 1 minute and then the resultant N and E removed mixture was lysed to remove the RBC's and then analyzed. FIG. 25A illustrates a control WBC subset sample without a microsphere bound thereto, a T₄ reading with a 2.2 micron non-magnetic microsphere bound thereto and a T reading with a 3.0 micron non-magnetic microsphere o bound thereto. This illustrates the separation between the two shifted WBC subset populations. FIG. 25B is a scattergram analysis with only the T₄WBC subset population bound to the 2.2 micron microspheres shifted to area A and FIG. 25C is a scattergram analysis with only the T_ WBC subset o population bound to the 3.0 micron microspheres shifted to area B. FIG. 25D illustrates a scattergram analysis with both the T₄ and Τθ WBC subset populations shifted to the respective areas A and B. This allows a simultaneous analysis of both the T₄ and Τθ subset populations.

Referring now to FIGS. 26A-D, three populations of L's, M's and G's are illustrated on four different scattergrams utilizing different parameters. Although the previous examples have been illustrated utilizing DC vs. opacity (RF/DC), the scattergrams can be formed utilizing virtually any two different parameters. FIG. 26A illustrates a scattergram utilizing DC vs. RF alone, FIG. 26B utilizes RF vs. opacity, FIG. 26C utilizes DC-RF vs. opacity and FIG. 26D utilizes DC vs. opacity as previously illustrated. Further, although DC vs. RF or RF/DC has been utilized, any two different frequencies are adequate as long as the signals are separable from each other, because of their frequency spectrum location and/or the difference in phase relationship. Opacity is a preferable parameter since it essentially is a normalization of the RF signal. Clearly, as illustrated in FIGS. 26A-D, the presentation of the data can be varied as desired. DC is a function of volume of the cell or formed body sensed, while RF is a function of the internal conductivity and volume of the sensed cell or formed body.

Referring now to FIGS. 27-46, the embodiments of the present invention are illustrated.

Referring to FIG. 27, a first embodiment of a method and apparatus for performing classification of cells such as a multipart differential is designated generally by the reference numeral 500. The instrument or analyzer 500 includes a biological sample 502, which contains at least a first set of viable biological cells (not illustrated), including at least two white blood cell populations, such as in or from a whole blood sample.

The cells of the biological sample 502 are to be involved in a biological reaction in a quantitative and/or qualitative determination or analysis. The biological sample 502 can include a buffer into which the cells are added.

The biological sample 502 is combined via a line 504 with at least one reactant 506 via a line 508. In the analyzer 500, the RBC's are removed from the mixture at an RBC removing station 510. As stated in the first parent application, the RBC's can be removed from the station 510 in a number of ways, such as enumerated with respect to the station 20.

A first portion of the mixture with the BBC's removed, then is fed to a WBC analyzer 512 via a line 514. This obtains a standard or control for the total or whole WBC populations of the biological sample 502. The analyzer 512 can be the same as the analyzer 86 or can be a l^ght sensing analyzer, such as described _in__ju. S. Serial No. 025,442__filed March 13, 1987 and U.S. Serial No. jl29_f954, filed December 4, 1987, entitled MULTI-PART DIFFERENTIAL ANALYZING APPARATUS UTILIZING 'LIGHT * SCATTER TECHNIQUES, which are incorporated herein by reference. The single sensing parameter can be electronic, such as RF or DC or light, such as median angle light scatter (Scatter) or any other desired light parameter.

A second portion of the mixture is fed to a N removing station 516 via a line 518. The N's are removed by the addition of the appropriate magnetic micjospheres with the N specific antibody bound thereto. In this example, the particular N specific antibody utilized is disclosed in Case 168,306, MONOCLONAL ANTIBODY SPECIFIC TO NEUTROPHILS, filed December 8, 1986, now U.S. Serial No. 938,864, which is incorporated herein by reference. A magnet or magnetic field is utilized, as before discussed, to remove the magnetically bound cells from the mixture. The remaining mixture with the N's removed then is fed via a line 520 to the analyzer 512. The analyzed results of this portion of the mixture then can be compared with the analyzed results of the first mixture portion in a comparator 522 to obtain the percentage of N's in the biological sample 502.

A third portion of the mixture is fed to a N and E removing station 524 via a line 526. The N's and ci

E's are removed by the addition of appropriate magnetic microspheres with the N and E specific antibody bound thereto. One such exemplary N and E specific antibody is disclosed in U.S. Serial NO. 068,618, entitled MONOCLONAL ANTIBODY SPECIFIC TO A COMMON DETERMINANT SITE OF NEUTROPHILS AND EOSINOPHILS. filed June 3, 1987, which is incorporated herein by reference. Separate N and E specific antibodies, bound to the same or separate magnetic microspheres, also can be utilized, where appropriate or as developed. The remaining mixture with the N's and E's removed then is fed via a line 528 to the analyzer 512. The analyzed results of this portion of the mixture then is compared to the results of the first and second mixture portions in the comparator 522 to obtain the percentage of E's and M's in the biological sample 502.

A fourth portion of the mixture is fed to a L and N removing station 530 via a line 532. The L's and N's are removed by the addition of the appropriate magnetic microspheres with the L and N specific antibody bound thereto. The N specific antibody can be either of the above referenced N specific antibodies, or other appropriate antibodies. The L specific antibody can be an L specific antibody as developed or a combination of the specific antibodies sold under the nomenclature Til and 2H4 by Coulter Immunology Division of Coulter Corporation, which together bind all the L's. The remaining mixture with the L's and N's removed then is fed via a line 534 to the analyzer 512. The analyzed results of this portion of the mixture then can be compared to the results of the other mixture portions to obtain the percentage of B's and L's in the biological sample 502.

Thus, the analyzer 500 performs a single classification of cells, such as N's utilizing lines or channels 514 and 518, E's and/or N's and/or M's utilizing lines 514, 518 and 526 and a full five part WBC differential utilizing all four lines. One most important feature of the analyzer 500 is that the mixtures can be analyzed utilizing only a single analyzing parameter, such as one electronic parameter or one light parameter. Other combinations can be utilized, but in each case only a single sensed parameter or characteristic is necessary to perform the classification of the invention.

FIG. 28 illustrates a specific analyzing instrument embodiment incorporating the method and apparatus of the analyzer 500 designated generally by the reference numeral 540. The instrument 540 includes an aspirator pumping mechanism 542 which is utilized to draw the biological sample of interest, for example the sample 502, into the instrument 540. The aspirator 542 is coupled via a line 544 to a sampling valve 546, which can be coupled to a sample probe 548. The biological sample 502 then is fed via a line 550 and a multipart valve 551 into the separate channels 514, 518, 526 and 532.

Describing first the channel 514, the sample portion is fed to a chamber 552. The chamber can be a mixing chamber into which the sample and reactant is fed to remove the RBC's. For example, utilizing lyse, the RBC's are lysed in the chamber 552 by adding the appropriate lyse thereto and preferably mixing therewith, then when the reaction is completed, a quench or fix is supplied to the chamber 552.

Specific details of an appropriate mixing apparatus, which can be utilized herein are disclosed in W088/06918 . entitled

METHOD AND APPARATUS FOR RAPID MIXING OF SMALL VOLUMES FOR ENHANCING BIOLOGICAL REACTIONS, which is incorporated herein by reference. By utilizing the mixer, the reactions are greatly enhanced in speed without significantly damaging the properties of interest of the cells, such as, can occur by raising the reaction temperature. Further, the reactions generally are completed in significantly less than a minute, generally on the order of fifteen seconds or less. This allows a rapid analysis of the automatic high volume analyzer instrument 540.

The quenched reactant mixture with the RBC's removed by the lyse then is fed via a line 554 to a multipart valve 556, or directly to a WBC analyzer 558 via a line 560. The analyzer 558 can be of many physical types in accordance with the counting and sizing techniques described by Wallace H. Coulter in U.S. Patent No. 2,656,508 utilizing light or electronic sensing as embodied in the numerous commercial blood cell counters of the assignee, Coulter Electronics, Inc.

The analyzer 558, in general, includes a flow sensor or sensing chamber 562. The chamber 562 includes a transducer 564 which has an aperture therethrough. The chamber 562 can include a first portion 566 which has a first electrode 568 in contact with the fluid therein. The chamber portion 566 and the electrode 568 can communicate through the sensing aperture with a second chamber portion 570 having a second electrode 572 therein.

The electrodes 568 and 572 are coupled via reactive leads to an RF/DC source and sensing circuit 574. The circuit 574 couples either or both a DC, or low frequency current or signal, and a high frequency signal between the electrodes 568 and 572.

The low frequency signal is utilized to sense the amplitude of a signal pulse caused by a cell passing through the sensing aperture. The high frequency signal can be utilized in the same manner as a single parameter or with the low frequency signal to obtain the electrical opacity of the same cell passing through the sensing aperture.

The measuring of the electrical opacity of cells was described by Wallace H. Coulter and Walter

R. Hogg in U.S. Patent No. 3,502,974 and several patents and publications of the assignee, Coulter Electronics, Inc., since that patent. One specific circuit which can be utilized herein is disclosed in Case 168,008, entitled PARTICLE ANALYZER FOR MEASURING THE RESISTANCE AND REACTANCE OF A PARTICLE, filed October 21, 1986 as U.S. Serial No. 921,654, now U.S. Patent No. 4,791,355, which is incorporated herein by reference.

The signals generated by the circuit 574 from the sensed cells are coupled via a DC signal lead 576 and/or an RF signal lead 578 to a comparator 580 (like the comparator 26). The comparator 580 can hold the signal generated from the first portion,

i.e., those without the WBC population or population subset subtracted, for a comparison with the results from the subsequent portions described hereinafter.

The analyzer 558 can include a sheath flow to focus the cells in the sensor 562, in the well known manner. The sheath flow can be provided by a fluidic system 582, coupled to the sensor in a known manner. The analyzer 558 has been illustrated with both RF and DC analyzing circuitry for example purposes only. In obtaining the multipart WBC population or subset population characterization of the invention, only a single sensing parameter, electronic or optical, need be utilized. In the case of electronic sensing, the parameter can be either DC or RF. Utilizing optical sensing, not illustrated, again only a single parameter such as median angle light scatter need be utilized. This one dimension sensing can simplify the instrument 540, as well as decrease the cost thereof.

A second portion of the sample mixture is fed through the valve 551 via the line 518 to the N removing station 516. The station 516 includes a mixer or chamber 584. The mixing chamber 584 has the second mixture portion fed thereto via the line 518. The mixer 584 includes all of the various options above described and, for example, includes a lyse input line for the RBC lyse.

When the lyse is utilized, after mixing as illustrated functionally at 586, then the quench is added via a quench line. At the same time or sequentially, the N's are being removed by the addition of the appropriate magnetic microspheres with the N specific antibody bound thereto from a source of microspheres 588 fed to the chamber 584 via a line 590. A magnet 592 or magnetic field is then utilized to remove the magnetically bound cells on the magnetic microspheres. The mixed and quenched mixture than is fed via the line 520 through the valve 556 and the line 560 to the WBC analyzer 558 to be analyzed as before described. The analyzed mixture with the N's removed then is compared in the comparator 580 to determine the percentage of N's in the sample 502.

A third mixture portion of the sample 502 is fed via the line 550 and the valve 551 via the line 526 to the N and E removing station 524. The station 524 includes a mixing chamber 594. In the third portion, the RBC's are removed by the RBC lyse fed into the chamber 594. The lyse is mixed with the sample portion and then a quench is added via a quench line. The N's and E's are removed by magnetic microspheres having the N and E specific antibody or antibodies bound thereto from a microsphere source 596 fed into the chamber 594 via a line 598. The microspheres are mixed, functionally at 600, and then the bound N and E microspheres are magnetically removed, functionally at 602. The N and E removed mixture than is fed via the line 528 to the valve 556 and via the line 560 to the analyzer 558 to also obtain the above mentioned results.

The instrument can be utilized with the first two channels 514 and 518 to determine the N percentage or with the first three channels 514, 518 and 526 to obtain the N's and E's percentages and/or the M's percentage, as desired. To obtain further

WBC population or subset population characterizations a fourth portion of the sample mixture 502 is fed via the line 550 and the valve 551 via the line 532 to the L and N removing station 530. Again, the RBC's are removed such as by lysing in a chamber 604, and the L's and N's are removed by binding the L's and N's to magnetic microspheres having the L and N specific antibody or antibodies bound thereto from a source 606 fed into the mixing chamber 604 via a line 608. The microspheres are mixed, functionally at 610, and then the magnetically bound L and N microspheres are magnetically removed, functionally at 612.

The L and N removed mixture then is fed via the line 534 to the valve 556 and via the line 560 to the analyzer 558 to obtain the above-mentioned results.

Utilizing combinations of the results from the other channels, the percentage of L's and/or B's then can be obtained such as to perform a full five part WBC differential to obtain the percentage of N's, E's, M's, L's and B's. The mixers include appropriate rinse lines and waste lines and the instrument 540 can include a probe rinse 614 to cleanse the instrument 540 prior to aspirating the next sample or sample portion for analyzing. Further, the sample 502 can be diluted from a source 616 via a line 618 if desired.

Only one specific hardware embodiment incorporating the method and apparatus of the analyzer 500 has been illustrated, but like the embodiments in the parent application, the analyzing instrument 540 can be implemented in numerous configurations. For example, the analyzer 540 could include a single channel, such as the channel 518 and the portions each can be run sequentially through the station 516 with the appropriate WBC population or populations removed from each portion, as previously described with respect to the separate channels.

Referring now to FIGS. 29A-D and FIGS. 30A-D, two sets of one dimensional scattergram multipart characterization results are illustrated, obtained from a whole blood sample, utilizing a prototype analyzing method similar to the analyzer instrument 540. The biological sample in each case was a 28 microliter sample of whole blood, which was combined with 122 microliters of buffer solution for the sample portion utilized in the first channel 514. The sample portion was lysed with 300 microliters of the RBC preferential lyse above referenced in the chamber 552. The sample portion was lysed for 4 seconds and then quenched with 120 microliters of quench before being fed to the analyzer 558 via the line 554, the valve 556 and the line 560. The results of analyzing utilizing a one dimensional electronic sensing parameter are illustrated in FIGS, 29 and 30. DC was utilized to obtain the data in FIGS. 29A-29D and RF was utilized to obtain the data (for comparison) in FIGS. 30A-30D, utilizing the same sample portion and measured at the same time in the analyzer 558. This results in two clearly identifiable data peaks 620 and 622 in FIG. 29A and peaks 624 and 626 in FIG. 30A. Peaks 620 and 624 are indicative of the percentage of L's and B's in the sample. Peaks 622 and 626 are indicative of the percentage of N's, E's and M's. Clearly, in one dimension, without further manipulation, the individual percentages are masked by the competing cells in the same data peak. As described in the above referenced parent application, this is not a problem, at least for some cells when greater than one parameter is utilized to differentiate the data.

In the second channel 518, a second whole blood sample portion of 28 microliters is combined with 40 microliters of magnetic microspheres with the N specific antibody bound thereto and combined with 82 microliters of buffer solution in the chamber 584. The sample portion was mixed for 60 seconds, lysed and quenched in the same manner as in the channel 514 and then placed in the magnetic field 592 for 30 seconds before the mixture with the N's removed is fed to the analyzer 558 via the line 520, the valve 556 and the line 560. This results in two data peaks 628 and 630 in FIG. 29B and two data peaks 632 and 634 in FIG. 30B. Peaks 628 and 632 remain the same as the peaks 620 and 624 although their percentage of the sample mixture portion now is greater, while the peaks 630 and 634 are indicative of the percentage of the E׳s and M's with the N's removed. The data peaks 630 and 634 can then be compared with the respective data peaks 622 and 626 to determine the percentage of N's in the whole blood sample.

Next, or in any order including substantially simultaneously, a third 28 microliter sample portion is fed to the third channel 526 and mixed with 20 microliters of magnetic microspheres with the E and N specific antibody or antibodies bound thereto and combined with 102 microliters of buffer solution in the chamber 594. The sample portion was mixed for 30 seconds, lysed and quenched in the same manner as in the channel 514 and then placed in the magnetic field 602 for 30 seconds before the mixture with the N's and E's removed is fed to the analyzer 558 via the line 528, the valve 556 and the line 560. This results again in two data peaks 636 and 638 in FIG. 29C and data peaks 640 and 642 in FIG. 30C. Peaks 636 and 640 again are the same contribution as the peaks 620 and 624, while the data peaks 638 and 642 are indicative of the percentage of the M's in the whole blood sample as compared to the data peaks 622 and 626. The data peaks 638 and 642 then can be compared to the data peaks 630 and 634 also to determine the percentage of E's in the whole blood sample.

A fourth 28 microliter sample portion is fed to the fourth channel 532 and mixed with 70 microliters of magnetic microspheres with a CD2 specific antibody bound thereto and 50 microliters of magnetic microspheres with a CD45R specific antibody bound thereto in the chamber 604. The sample portion was mixed for 2 minutes and then placed in the magnetic field 612 for 30 seconds and then the remaining mixture is removed to a holding chamber 644 via a line 646. The holding chamber 644 currently appears to be a necessary operation, because the specific antibodies utilized as above referenced under the nomenclature Til and 2H4 and the N specific antibody, appear to interfere with one another when utilized simultaneously. It is not known whether this is due to the specific antibodies or to the nature of the cells themselves. Once the mixture with the Til and 2H4 bound cells removed is fed into the holding chamber 644, the chamber 604 then is rinsed with the magnetic field removed to remove the magnetic microspheres having the CD2 and CD45R cell clusters bound thereto.

The N bound magnetic microspheres then are isolated in the chamber 604, which can be provided by another source, other than the source 606 (not illustrated). The isolation is accomplished by holding the magnetic microspheres with 40 microliters of the N specific antibody bound thereto in the magnetic field 612 and removing the buffer solution to waste. Alternately, the mixture can be adjusted so that the buffer solution is utilized as part of the mixture or a concentrated volume of magnetic microspheres can be utilized and the solution need not be utilized. The sample portion then is returned to the chamber 604 from the chamber 644 via a line 648 and mixed with the magnetic microspheres with the N specific antibody bound thereto, lysed and quenched as in the channel 514 and then again placed in the magnetic field 612 for 30 seconds before the mixture with all the L's and N's removed is fed to the analyzer 558 via the line 534, the valve 556 and the line 560. This results in two data peaks 650 and 652 in FIG. 29D and two data peaks 654 and 656 in

FIG. 30D. Peaks 650 and 654 represent only the B's, since all the L's have been removed. Since the L's are about 30 percent of a normal whole blood sample, this enhances the B's which originally are about 1 percent of the sample to a very significant data peak (i.e., amount of data). The B's are further enhanced since the N's also were removed from the peaks 652 and 656 and they originally are about 60 percent of the sample. Hence, the B's now represent about 10 percent of the remaining B, M and E cells.

The actual percentage calculations are performed as follows, with the data peak numbers calculated by dividing the data peak (number of cells counted in the peak) by the total data from both peaks (utilizing FIGS. 29A-29D for example purposes):

1) M% - determined from channel 526:

Γ(Pkl (620)) (Pkl (636))1 XX Pk2 (638) = M%

2) M+E% - determined from channel 518:

r(Pkl (620)) (Pkl (628))1 xx Pk2 (630) = M+E%

3) E% = M+E% - M%

4) N% = (Pk2 (622)) - M+E%

5) B% - determined from channel 532:

Γ(Pk2 (630)) (Pk2 652))1 XX (Pkl (650)) =8¹%

B¹% XX Γ(Ρ1 (620)) (Pkl (628))1 = B%

6) L% = (Pkl (620)) ־ B%

For the data illustrated in FIGS. 29 and 30, the calculations from the RF and DC data are set forth in Table II.

TABLE II

DC RF

<td> Channel</td><td> Pkl</td><td> Pk2</td><td> Pkl</td><td> Pk2</td>

<td> 514</td><td> 28.1</td><td> 71.9</td><td> 30.3</td><td> 69.7</td>

<td> 518</td><td> 74.4</td><td> 25.6</td><td> 74.1</td><td> 25.9</td>

<td> 526</td><td> 83.8</td><td> 16.2</td><td> 83.4</td><td> 16.6</td>

<td> 532</td><td> 10.9</td><td> 90.1</td><td> 10.0</td><td> 90.0</td>

A full five part differential in percentage of the N's, L's, M's, E's and B's also was calculated from the DC and RF data peaks and compared to a light sensing instrument for verification purposes, such as described in U.S. Serial No. 025,442.

TABLE III

PART DIFFERENTIAL

<td> LIGHT</td><td> DC</td><td> RF</td>

<td> N 61.58</td><td> N 62.2</td><td> N 59.1</td>

<td> L 28.50</td><td> L 26.9</td><td> L 29.1</td>

<td> M 6.27</td><td> M 5.4</td><td> M 6.0</td>

<td> E 3.10</td><td> E 4.3</td><td> E 4.6</td>

<td> B 0.56</td><td> B 1.2</td><td> B 1.2</td>

Referring now to FIGS. 31A-D and FIGS. 32A-D, a second two sets of one dimensional scattergram multipart characterization results are illustrated, obtained from a second whole blood sample, again utilizing a prototype analyzing method similar to the analyzer instrument 540. The biological sample in each case again was a 28 microliter sample of whole blood, prepared for each channel as described with respect to FIGS. 29 and 31. The sample portion was lysed in the first channel 514 in the chamber 552 and then quenched before being fed to the analyzer 558. The results of analyzing utilizing a one dimensional electronic sensing parameter are illustrated in

FIGS. 31 and 32. DC was utilized to obtain the data in FIGS. 31A-31D and RF was utilized to obtain the data (for comparison) in FIGS. 32A-32D, utilizing the same sample portion and measuring at the same time in the analyzer 558. This results in two clearly identifiable data peaks 658 and 660 in FIG. 31A and peaks 662 and 664 in FIG. 32A. Peaks 658 and 662 are indicative of the percentage of L's and B's in the sample. Peaks 660 and 664 are indicative of the percentage of N's, E's and M's. Again, in one dimension, without further manipulation, the individual percentages are masked by the competing cells in the same data peak.

In the second channel 518, a second whole blood sample portion is combined with the magnetic microspheres with the N specific antibody bound thereto in the chamber 584, mixed, lysed and quenched and then placed in the magnetic field 592 before the mixture with the N's removed is fed to the analyzer 558. This results in two data peaks 666 and 668 in FIG. 31B and two data peaks 670 and 672 in FIG. 32B. Peaks 666 and 670 remain the same as the peaks 568 and 662 although their percentage of the sample mixture portion now is greater, while the peaks 668 and 672 are indicative of the percentage of the E's and M's with the N's removed. The data peaks 668 and 672 can then be compared with the respective data peaks 660 and 664 to determine the percentage of N's in the whole blood sample.

Next, or in any order including substantially simultaneously, a third sample portion is fed to the third channel 526 and mixed with the magnetic microspheres with the E and N specific antibody or antibodies bound thereto in the chamber 594, mixed, lysed and quenched and then placed in the magnetic field 602 before the mixture with the N's and E's removed is fed to the analyzer 558. This results again in two data peaks 674 and 676 in FIG. 31C and data peaks 678 and 680 in FIG. 32C. Peaks 674 and 678 again are the same contribution as the peaks 658 and 662, while the data peaks 676 and 680 are indicative of the percentage of the M's in the whole blood sample as compared to the data peaks 660 and 664. The data peaks 676 and 680 then can be compared to the data peaks 668 and 672 also to determine the percentage of E's in the whole blood sample.

A fourth sample portion is fed to the fourth channel 532 and mixed with the magnetic microspheres with a CD2 specific antibody bound thereto and the magnetic microspheres with a CD45R specific antibody bound thereto in the chamber 604, mixed, then placed in the magnetic field 612 and then the remaining mixture is removed to the holding chamber 644.

The N bound magnetic microspheres then are isolated in the chamber 604 by holding the magnetic microspheres with the N specific antibody bound thereto in the magnetic field 612 and removing the buffer solution. The sample portion then is returned to the chamber 604 after it is rinsed from the chamber 644 via a line 648 and mixed with the magnetic microspheres with the N specific antibody bound thereto, lysed and quenched and then again placed in the magnetic field 612 before the mixture with all the L's and N's removed is fed to the analyzer 558. This results in two data peaks 682 and 684 in FIG. 31D and two data peaks 686 and 688 in FIG. 32D. Peaks 682 and 686 represent only the B's, since all the L's have been removed to enhance the B's to a very significant data peak (i.e., amount of data). The B's are further enhanced since the N's also were removed from the peaks 684 and 688 and hence from the remaining sample portion.

The actual percentage calculations are performed as before as set forth hereinafter, with the data peak numbers calculated by dividing the data peak (number of cells counted in the peak) by the total data from both peaks (utilizing FIGS. 31A-31D for example purposes):

1) M% - determined from channel 526:

((Pkl (658)) (Pkl (674))1 XX Pk2 (676) = M%

2) M+E% - determined from channel 518:

f(Pkl (658)) (Pkl (666))1 XX Pk2 (668) = M+E%

3) E% = M+E% - M%

4) N% = (Pk2 (660)) - M+E%

5) B% - determined from channel 532:

Γ(Pk2 (668)) (Pk2 (684))1 XX (Pkl (682)) = 8¹%

B^X% xx [(Pkl (658)) (Pkl (666))1 = B%

6) L% = (Pkl (658)) - B%

For the data illustrated in FIGS. 31 and 32, the calculations from the RF and DC data are set forth in Table IV.

TABLE IV

DC RF

<td> Channel</td><td> Pkl</td><td> Pk2</td><td> Pkl</td><td> Pk2</td>

<td> 514</td><td> 24.0</td><td> 76.0</td><td> 26.0</td><td> 74.0</td>

<td> 518</td><td> 63.3</td><td> 36.7</td><td> 62.6</td><td> 37.4</td>

<td> 526</td><td> 76.0</td><td> 24.0</td><td> 75.2</td><td> 24.8</td>

<td> 532</td><td> 10.6</td><td> 89.4</td><td> . 9.7</td><td> 90.3</td>

A full five part differential in percentage of the N's, L's, M's, E's and B's again was calculated from the DC and RF data peaks and again compared to a light sensing instrument for verification purposes, such as described in U.S. Serial No. 025,442.

TABLE V

PART DIFFERENTIAL

<td> LIGHT</td><td> DC</td><td> RF</td>

<td> N 60.37</td><td> N 62.1</td><td> N 58.5</td>

<td> L 24.70</td><td> L 22.4</td><td> L 24.3</td>

<td> M 8.62</td><td> M 7.6</td><td> M 8.6</td>

<td> E 5.12</td><td> E 6.3</td><td> E 6.9</td>

<td> B 1.18</td><td> B 1.6</td><td> B 1.7</td>

The calculations are set forth below utilizing the DC data peaks:

<td> 1)</td><td> M%</td><td> 24.0 XX 76.0</td><td> 24.0 =</td><td> 7.6</td>

<td> 2)</td><td> M+E% =</td><td> 24.0 XX 63.3</td><td> 36.7 =</td><td> 13.9</td>

<td> 3)</td><td> E%</td><td> (13.9) -</td><td> • (7.6)</td><td> = 6.3</td>

<td> 4)</td><td> N%</td><td> (76.0) -</td><td> (13.9) ־</td><td> 1 = 62.1</td>

<td> 5)</td><td> B%</td><td> 36.7 XX</td><td> 10.6 =</td><td> 4.4</td>

89.4

4.4 xx 24.0 = 1.6

63.3

6) L% = 24.0 - 1.6 = 22.4

The data peaks in FIGS. 29-32 were depicted utilizing a single electronic sensing parameter, either DC or RF. Opacity was not illustrated, but also could be utilized if desired, since it is RF/DC as previously described. A single light sensing parameter also can be utilized, for example, median angle light scatter (Scatter), as illustrated in FIGS. 33-36.

Referring to FIG. 33, the M's, L's, N's and E's groups of cells are clearly separated by utilizing two parameters, Scatter and electrical volume. The B's are obscured in this data pattern. However, in one dimension, the same scatter data illustrated in FIG. 34 now results in the M's obscuring the L's or vice versa as seen in data peak 690. The N's and E's are illustrated in data peak 692 and the E's in data peak 693, representing the same data as in FIG. 33.

One method of solving the problem of the obscured data in the data peak 690 is to remove the M's. Currently this would be accomplished in an offline or prepreparation mode, since the M's are removed slowly when utilizing a CD14 specific antibody, such as M02 sold by Coulter Immunology Division of Coulter Corporation. For example, 400 microliters of a whole blood sample are combined with 200 microliters of a 2-1/2 percent solution of magnetic microspheres with the CD14 specific antibody bound thereto. The magnetic microspheres are first isolated by removing the fluid therefrom while holding the microspheres in a magnetic field. The sample then is added and the mixture is gently mixed, such as by rocking for about 30 minutes and then placed in a magnetic field for about 5 minutes after which the preprepared mixture, with the M's removed is analyzed in the instrument 540 as previously described. The data is illustrated again in two dimensions for comparison purposes in FIG. 35, where it clearly can be seen that the M's have been depleted by comparison with FIG. 33, enhancing the remaining WBC population data.

The one dimensional scatter data is illustrated in FIG. 36, again resulting in two data peaks 694 and 696. The peak 694 is the data peak 690 with the M's removed, leaving only the L's. The peak 696 is the same as the data peak 692, and peak 697 is the same as peak 693, .both peaks 696 and 697 are enhanced by the removal of the M's from the sample portion.

Although not specifically illustrated, the sample mixture with the M's removed as illustrated in peak 694, now can be further depleted to perform L subset analyses, as will be further described hereinafter.

Although the analyzer 500 is illustrated for explanation purposes utilizing four separate channels, this only enhances the speed of the classification method of the invention. The invention also can be practiced utilizing a single channel, with the different portions of the biological sample 502 being processed sequentially.

FIG. 37 illustrates an analyzer embodiment for a method and apparatus of enhancing small or obscure populations for classification thereof designated generally by the reference numeral 700. This method and apparatus of the invention can be utilized to determine such small populations as the B's or subsets of the L's. The analyzer 700 includes a biological sample 702, which contains at least a first set of viable biological cells (not illustrated), such as in or from a whole blood sample. If the classification is to be of B cells, then the sample 702 will include at least the B cell population and at least one other WBC population, such as the L cells. Generally the sample 702 would at least include all of the WBC populations, however, as previously described, various populations or subsets thereof can be eliminated offline or in a pre-preparation step. If the classification is to be of a WBC population subset, then the sample 702 will include at least one WBC population having at least one definable subset.

Describing first the classification of B cells, the B cells are a very small population of the total

WBC populations, generally on the order of about less than one percent. Clearly, eliminating the WBC populations which obscure the B cells, will enhance the analysis and classification of the B's, because the B's then become a much greater and significant part of the remaining WBC population, as the other WBC populations are eliminated. Clearly, also, this enhancement will be true for all small or obscured cell populations of interest.

In analyzing the B cell populations utilizing a single measuring dimension or parameter, for example RF as illustrated in FIG. 38 to be described hereinafter, the B's are obscured by the L's in a single peak 704. The L's are around thirty (30) percent of the total WBC population and hence the B's still are only about three (3) percent even of only the L's and B's together. Therefore, to more definitely analyze and classify the B's, the L's are totally or substantially eliminated from the sample.

The sample 702 is combined via a line 706 with at least one reactant 708 via a line 710. The RBC's are removed in an RBC removal station 712 by one of the methods previously described. Once the RBC's are removed, a first portion of the resulting mixture is fed via a line 714 to a WBC analyzer 716. The WBC analyzer can be the same as those previously described, or minor variations thereof. The single sensing parameter can be electronic, such as RF or DC or light, such as Scatter or any other desired light parameter.

A second portion of the mixture is fed via a line 718 to a L removal station 720, wherein the L cells are bound to magnetic microspheres which include an L specific monoclonal antibody or antibodies bound thereto. The remainder of the mixture with at least the B cells remaining is fed via a line 722 to the WBC analyzer 716. The results of the two analyzed portions are fed to a comparator 724 via a line 726, where the two analyzed results are compared to determine the percentage of B's in the sample 702. The B's by this method have been made to change from about one to three percent of the sample mixture to substantially one hundred percent in the first data peak 704, providing definitive analysis and characterization. In a like manner, when the CD or other WBC population group chosen is small, all or some of the rest of the L's can be removed enhancing the analyzation of the remaining CD group of interest.

Next, describing the analysis and classification of one or more WBC population subsets, for example, the CD2, CD4 or CD8 WBC population subsets. The sample 702 again will include at least a first set of viable biological cells (not illustrated), such as in or from a whole blood sample. The sample 702 will include at least the WBC population subset of interest and at least one other obscuring WBC population or population subset and generally will include all the WBC populations.

The sample 702 again is fed to the RBC removal station 712 and then a first portion is fed to the WBC analyzer 716 via the line 714. A second portion will be utilized to determine the CD2 group, for example, and thus the second portion will be mixed with magnetic microspheres which include a CD2 specific monoclonal antibody bound thereto, such as Til sold by Coulter Immunology Division of Coulter Corporation. The remainder of the mixture, with the CD2 cells now removed, will be fed via the line 722 to the WBC analyzer 716. The two analyzed results then are compared in the comparator 724 to provide the desired characterization of the CD2 group of cells.

The operation of the analyzer 700 can be performed on the instrument 540, utilizing the respective channels as desired or on a further multichannel instrument or again on a single channel instrument in a sequential fashion.

Referring now to FIGS. 38A-38E, the CD4, CD8 and CD2 subsets were determined as depicted in the one dimensional scattergram characterization results illustrated, utilizing a prototype analyzing method similar to the analyzer instrument 540. The biological sample in each case was a 28 microliter sample of whole blood. The sample was combined with 122 microliters of buffer solution for a control sample utilized in the channel 714 (which can be the channel 514 of the instrument 540). The results of a one dimensional electronic sensing parameter, here RF, was utilized to obtain the data for FIGS. 38A-E. The sample portion was lysed for 4 seconds with 300 microliters of the RBC preferential lyse above referenced (such as in the chamber 552) and then quenched with 120 microliters of quench before being fed to the analyzer 716 (such as the analyzer 558). This results in two clearly identifiable data peaks 704 and 728 in FIG. 38A. Peak 704 includes the B's and L's and all subsets thereof as a single peak. The B's are a small enough percentage so as to not effect the analyzation of the desired L subset, however, the value of the B's could be subtracted if desired.

A second control was utilized by combining a second whole blood sample portion of 28 microliters with 50 microliters of magnetic microspheres without any L or L subset specific antibody bound thereto and 72 microliters of buffer solution. The sample portion was lysed and quenched as before and then fed to the analyzer 716. This results in two data peaks 730 and 732 in FIG. 38B. The data peaks 730 and 732 are substantially identical to the peaks 704 and 728, hence the inclusion of the microspheres did not appear to have any deleterious effects on the analysis.

A third 28 microliter sample portion is fed to the channel 718 (which can be any one of the channels 518, 526 and 532 of the instrument 540), combined with 50 microliters of the magnetic microspheres with a CD4 specific antibody bound thereto and 72 microliters of the buffer solution. The CD4 specific antibody can be T4 sold by Coulter Immunology Division of Coulter Corporation. The sample portion was mixed for 60 seconds, lysed and quenched as before and then placed in a magnetic field for 30 seconds, before the mixture with the CD4 subset population removed is fed to the analyzer 716. This results in two data peaks 734 and 736 in FIG. 38C. The peak 734 represents the L's without the CD4 subset population and then is compared to the peak 704 by the comparator 724 to obtain the percentage of the CD4 subset population in the sample.

Again, for testing and evaluation purposes, the same blood sample was analyzed in the above manner to obtain four sets of data peaks, one of which is actually depicted in FIGS. 38A-E. The data peaks in each set of data were substantially the same and hence a single set of data can be utilized. The data was averaged over the four sets of data to obtain the results. The average CD4 subset population percentage obtained was 45.7, which was compared with a light sensing instrument for verification purposes, such as the EPICS® flow cytometer available from Coulter Corporation, which provided a percentage of 47.6.

A fourth 28 microliter sample portion is fed to the channel 718, combined with 50 microliters of the magnetic microspheres with a CD8 specific antibody bound thereto and 72 microliters of the buffer solution. The CD8 specific antibody can be T8 sold by Coulter Immunology Division of Coulter Corporation. The sample portion was again mixed, lysed and quenched and placed in a magnetic field as before. The mixture with the CD8 subset population removed then is fed to the analyzer 716. This results in two data peaks 738 and 740 in FIG. 38D. The data peak 738 represents the L's without the CD8 subset population, which then is compared to the peak 704 by the comparator 724 to obtain the percentage of the CD8 subset population in the sample. The average CD8 subset population percentage obtained was 25.0, which was compared with the light sensing instrument for verification purposes, which provided a percentage of 26.0.

A fifth 28 microliter sample portion is fed to the channel 718, combined with 50 microliters of the magnetic microspheres with a CD2 specific antibody bound thereto and 72 microliters of the buffer solution. The CD2 specific antibody can be Til sold by Coulter Immunology Division of Coulter Corporation. The sample portion was again mixed, lysed and quenched and placed in a magnetic field as before. The mixture with the CD2 subset population removed then is fed to the analyzer 716. This results in two data peaks 742 and 744 in FIG. 38E. The data peak 742 represents the L's without the CD2 subset population, which then is compared to the peak 704 by the comparator 724 to obtain the percentage of the CD2 subset population in the sample. The average CD2 subset population percentage obtained was 82.7, which was compared with the light sensing flow cytometer instrument, which provided a percentage of 79.0.

The results of another subset analysis utilizing a one dimensional electronic sensing parameter of CD4, CDS and CD2 subset populations is illustrated in FIGS. 39A-E and 40A-E. DC was utilized to obtain the data in FIGS. 39A-E, while RF was utilized to obtain the data in FIGS. 40A-E, utilizing the same sample portion and measured at the same time.

The sample portion was lysed and quenched before being fed to the analyzer 716 in substantially the same manner as described with respect to FIGS. 38A-E. In the case of FIGS. 39A and 40A, only a buffer solution was added and in the case of FIGS. 39B and 40B, a buffer solution as well as magnetic microspheres without the L or L subset specific antibodies were combined with the sample. The control without microspheres resulted in data peaks 746 and 748 in FIG. 39A and data peaks 750 and 752 in FIG. 40A. Peaks 746 and 750 are representative of the L's and B's in the sample. The control with control microspheres combined with the sample, but with the microspheres removed therefrom utilizing the magnetic field, resulted in data peaks 754 and 756 in FIG. 39B and data peaks 758 and 760 in FIG. 4OB.

A third whole blood sample portion is combined with 50 microliters of magnetic microspheres with a CD4 specific antibody bound thereto. The mixture is mixed, lysed, quenched and placed in the magnetic field to remove the CD4 subset population for the sample portion mixture before it is fed to the analyzer 716. The DC analysis results in two data peaks 762 and 764 in FIG. 39C, while the RF analysis results in two data peaks 766 and 768 in FIG. 40C. The data peaks 746 and 762 are compared as are the data peaks 750 and 766 to obtain the percentage of the CD4 subset population in the sample.

In FIGS. 39 and 40, the data peaks are one of three separate sample sets from the same whole blood sample which were averaged to obtain the results. In the case of CD4, the percentage obtained from DC was 57.0, RF was 57.1 and the light sensing flow cytometer instrument was 54.6.

To obtain the CD8 subset population analysis, a fourth whole blood sample portion was combined with 50 microliters of magnetic microspheres with a CD8 subset population specific antibody bound thereto. The sample portion is mixed, lysed, quenched and held in a magnetic field to remove the CD8 subset population from the mixture, before the mixture is fed to the analyzer 716. The DC analysis results in two data peaks 770 and 772 in FIG. 39D, while the RF analysis results in two data peaks 774 and 776 in FIG. 40D.

The data peaks 746 and 770 are compared as are the data peaks 750 and 774 to obtain the percentage of the CD8 subset population in the sample. In the case of CD8, the percentage obtained from DC was 17.4, from RF was 18.6 and from the light sensing flow cytometer instrument was 17.7.

To obtain the CD2 subset population analysis, a fifth whole blood sample portion was combined with 50 microliters of magnetic microspheres with a CD2 subset population specific antibody bound thereto. The sample portion is mixed, lysed, quenched and held in a magnetic field to remove the CD2 subset population from the mixture, before the mixture is fed to the analyzer 716. The DC analysis results in two data peaks 778 and 780 in FIG. 39E, while the RF analysis results in two data peaks 782 and 784 in FIG. 40E.

The data peaks 746 and 778 are compared as are the data peaks 750 and 782 to obtain the percentage of the CD8 subset population in the sample. In the case of CD8, the percentage obtained from DC was 79.6 from RF was 79.3 and from the light sensing flow cytometer instrument was 74.7.

The B and L subset population analysis referred to with respect to FIGS. 37-40 was obtained utilizing a one dimensional electronic sensing parameter. A light sensing parameter also could be utilized, as well as two or more sensing parameters such as illustrated in FIGS. 41A-E.

The sample portions are handled in the same manner as those utilized to obtain the data in FIGS. 38-40. FIGS. 41A and 41B illustrate respectively, the results of a control without microspheres and a control combined with magnetic microspheres which are removed prior to analyzing. The controls illustrate the normal three part histograms, illustrating the L's, M's and G's.

The CD4 depletion is illustrated in FIG. 41C, following the magnetic depletion of the CD4 subset population, the remaining L population can be compared to the control L population to determine the CD4 subset population percentage. The CD4 subset population percentage was determined to be 59.4, which was then compared to the light sensing flow cytometer instrument which determined a percentage of 54.6.

The CD8 depletion is illustrated in FIG. 41D, following the magnetic depletion of the CD8 subset population, the remaining L population can be compared to the control L population to determine the CD8 subset population percentage. The CD8 subset population percentage was determined to be 15.8, which was then compared to the light sensing flow cytometer instrument which determined a percentage of 17.7.

The CD2 depletion is illustrated in FIG. 4IE, following the magnetic depletion of the CD2 subset population, the remaining L population can be compared to the control L population to determine the CD2 subset population percentage. The CD2 subset population percentage was determined to be 82.2, which was then compared to the light sensing flow cytometer instrument which determined a percentage of 74.7.

As can clearly be seen by the above analysis, a number of the subset populations overlap, since the individual L subset populations add to greater than 100. .Overlapping” is utilized herein to signify that certain cells, populations of cells, subpopulations of cells or formed bodies include at least two receptors or antigens of interest. Overlapping can be a significant parameter in diagnosis and treatment and will be discussed in further detail hereinafter.

All the data referred to heretofore, has been what would be called ”normal whole blood samples. Normal is utilized herein to signify that a whole blood sample is not substantially infected, such as by a cancer or other disease.

FIGS. 42 and 43 illustrate the results of analyzing two abnormal whole blood samples. The first sample depicted in FIGS. 42A-G was analyzed and displayed in several different manners. FIGS. 42A and 42B depict two different two dimensional sensing histograms of the whole blood/sample, one with light sensing and one with only electronic sensing, without any treatment of the blood sample. Clearly, the normal blood sample L, M and G grouping, for example, as illustrated in FIG. 41A is totally obscured and there is just one unidentifiable data grouping.

The results of two different treatments of the abnormal whole blood sample are illustrated in FIGS. 42C and 42D. In FIG. 42C, a 200 microliter portion of the sample was combined with 200 microliters of magnetic microspheres having a N and E specific antibody bound thereto. The mixture is mixed, lysed, quenched and held in a magnetic field while the remaining portion is removed and fed to the analyzer without the N and E bound cells therein. It appears clear that a substantial portion of the abnormal cells have been removed, since the pattern in FIG. 42C has become very much more defined than the pattern in FIG. 42B.

In the second treatment, a 200 microliter portion of the sample was combined with 200 microliters of magnetic microspheres having only a N specific antibody bound thereto. Although some of the cells have been removed, indicating that some are bound to the N antibody, a significant portion of the abnormal cells remain, especially as seen at the top of the histogram. It would therefore appear that some of the abnormal or diseased cells bind to the N+E antibody. This type of depletion treatment can be utilized for diagnosis and treatment of particular diseases.

The data histograms of FIGS. 42A-D were developed utilizing two dimensional sensing. The same information can be developed utilizing a single sensing parameter, for example, a single electronic sensing parameter as depicted in FIGS. 42E-42G. The one dimensional sensing, here DC, produces the histogram depicted in FIG. 42E when the sample is analyzed without any treatment. The single data peak and the data at the far right of the histogram are clear indications of an abnormal sample.

Again, the same treatment was utilized as referred to above with respect to FIGS. 42C and 42D and, in fact, the one dimensional sensing data was generated at the same time as the two dimensional sensing data. The analyzing instrument can, as described above, include multiple sensing parameters or only one single parameter. Again, the removal of the N and E bound cells produces a histogram in FIG. 42F, which again illustrates that most of the abnormal cells have been removed. The histogram in FIG. 42G illustrates again that a significant number of the abnormal cells have not been removed.

The results of analyzing the second abnormal whole blood sample are illustrated in FIGS. 43A-G. The results of analyzing the sample without treatment are illustrated in two dimensional histograms in FIGS. 43A and 43B. Clearly, a normal whole blood sample data pattern is not seen. The histogram of FIG. 43B prepared in the instrument, can be compared to the histogram in FIG. 43C prepared offline, which do not appear significantly different. A 28 microliter sample portion was prepared offline or preprepared before the analysis depicted in FIG. 43C.

A portion of the sample was depleted of the CD5 subset population and then analyzed to provide the histogram in FIG. 43D. A 28 microliter portion of the whole blood sample was combined with 122 microliters of magnetic microspheres having a CD5 specific antibody bound thereto, such as T1 sold by Coulter Immunology Division of Coulter Corporation. The mixture was mixed, lysed, quenched and held in a magnetic field to remove the CD5 bound cells. This clearly removed a significant portion of the abnormal cells as can be seen by comparing FIGS. 43B or

FIG. 43C with FIG. 43D. The histograms of FIGS. 43A-D were made with two dimensional sensing, while the same data is depicted in one dimension histograms in FIGS. 43E-G.

Again, no treatment was performed on the online sample depicted in FIG. 43E or on the offline sample depicted in FIG. 43F and the CD5 subset population was depleted from the sample depicted in FIG. 43G.

Also, although the method and the apparatus of the invention have been described utilizing whole blood samples, there, can be instances where it is desired to utilize a portion of a sample with the RBC׳s and/or some of the WBC populations removed. Clearly, the RBC's are still removed, but arguably externally and not within the apparatus of the invention. Such removal or prepreparation can be carried out in numerous conventional ways, such as utilizing a lysing reagent, density or centrifugation techniques, such as ficoll, dextran, buffycoat, etc. In an automated analyzer utilizing the invention, it would be preferable to utilize a whole blood sample for speed and integrity in the analysis of the sample.

Many modifications and variations of the present invention are possible in light of the above teachings. The samples 12 , 42, 150, 180, 294 , 322 and 342 can include whole blood, human body fluids containing cells, or other fluids containing formed bodies, such as bacteria, viruses and fungi. The volumes of microspheres specified are stated in weight of microspheres per volume of diluent. Although volumes on the order of about 20 microliters of sample, such as a whole blood sample, have been utilized for example purposes herein, smaller or larger sample volumes also can be utilized as desired. For example, as small as about 2 microliters of a sample up to whatever volume of sample is practical for the particular instrument or technique can be utilized. Although some of the examples were performed in sequential steps, the steps can also be performed simultaneously. A simultaneous analysis allows the least complex instrument module to be utilized. It is therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.