Method for Identifying T Cells Disease Involved in Autoimmune Disease

This invention relates to methods for identifying T cell populations involved in autoimmune disorders, such as rheumatoid arthritis. More specifically, it relates to quantifying particular T cell subpopulations via assaying for specific V.beta. elements. In addition, the invention relates to treatment of these conditions and disorders via administration of an agent which inhibits the particular T-cell subpopulation, identification of agents, such as superantigens and environmental factors involved in the development of autoimmune diseases, identification of subpopulations of T cell populations, and diagnosis of autoimmune diseases.

In recent years, the mechanism by which mammalian immune systems, such as human and murine systems react to infections, foreign antigens, and to so-called "self antigens" in connection with autoimmune diseases has begun to be established. See, in this regard, Grey et al., Scientific American 261(5): 56-64 (1989); Male et al., Advanced Immunology (J. P. Lippincott Company, 1987), especially chapters 6 through 10.

Well known, both to the skilled artisan and to the general public is the role of antibodies, sometimes referred to as "immunoglobulin" or the less correct and older "gammaglobulin" in response to infection. Antibodies are protein molecules which are produced by B cells in response to infection. It is well known that these antibodies act to "disable" or to inactivate infectious agents in the course of combating the infection.

In order for antibodies to be produced, however, preceding events must occur which lead to stimulation of the B cells which produce the antibodies. One of the key events involved in the processes leading to antibody production is that of antigen recognition. This aspect of the immune response requires the participation of so-called "T-cells", and is less well known than the antibody response commented on supra.

Briefly, and in outline form, antigen recognition requires interaction of an "antigen presentation cell", a "processed antigen", and a T-cell. See Grey and Male, supra. The "processed antigen", in an infection, is a molecule characteristic of the pathogen which has been treated, i.e., "processed", by other cells which are a part of the immune system. The processed antigen interacts with a receptor on the surface of an antigen presented in a manner not unlike a lock fitting into a key hole or, perhaps more aptly, two pieces of a jigsaw puzzle.

The configuration of the complex processed antigen and receptor on antigen presentation cell allows the participation of T-cells. T-cells do not join the complex unless and until the processed antigen has fit into the receptor on the antigen presentation cell. This receptor will hereafter be referred to by its scientific name, the major histocompatibility complex (MHC), or the human leukocyte antigen (HLA). Generally, MHC is used to refer to murine systems, and HLA to humans.

These receptors fall into two classes. MHC-II molecules are involved in most responses to pathogens. In contrast, MHC-I molecules are involved when the pathogen is a virus, or a malignant cell is involved. When MHC-I participation is involved, there is no antibody stimulation; rather, the interaction of MHC-I, processed antigen and T-cell leads to lysis of cells infected with the pathogen.

The foregoing discussion has focused on the events involved in responding to "infection", i.e., the presence of pathogenic foreign material in the organism. Similar mechanisms are involved in autoimmune diseases as well. In these conditions, the organism treats its own molecules as foreign, or as "self-antigens". The same type of complexing occurs as described supra, with an antibody response being mounted against the organism itself. Among the diseases in which this is a factor are rheumatoid arthritis, diabetes, systemic lupus erythrematosis, and others.

The ability of the T-cell to complex with the processed antigen and MHC/HLA complex is dependent on what is referred to as the T-cell antigen receptor, referred to as "TCR" hereafter. The TCR is recognized as a heterodimer, made up of alpha (.alpha.) and beta (.beta.) chains. Five variable elements, coded for by germline DNA and known as "V.alpha., J.alpha., V.beta., and J.beta..sub.3, and D.beta. " as well as non-germline encoded amino acids contribute to the TCR. See, in this regard, Marrack et al., Immunol. Today 9: 308-315 (1988); Toyonaga et al., Ann. Rev. Immunol. 5: 585-620 (1987); Davis, Ann. Rev. Immunol. 4: 529-59 (1985); Hendrick et al., Cell 30: 141-152 (1982). With respect to the binding of TCR with processed antigen and MHC, see Babbitt et al., Nature 317: 359-361 (1985); Buus et al., Science 235: 1353-1358 (1987); Townsend et al., Cell 44: 959-968 (1986); Bjorkman et al., Nature 329: 506-512 (1987).

Generally, both the alpha and beta subunits are involved in recognition of the ligand formed by processed antigen and MHC/HLA molecule. This is not always the case, however, and it has been found that so-called "superantigens" stimulate T-cells with a particular V.beta. element, regardless of any other element. See Kappler et al., Cell 49: 273-280 (1987); Kappler et al., Cell 49: 263-271 (2987); MacDonald et al., Nature 332: 40-45 (1988); pullen et al., Nature 335: 796-801 (1988); Kappler et al., Nature 332: 35-40 (1988); Abe et al., J. Immunol. 140: 4132-4138 (1988); White et al , Cell 56: 27-35 (1989); Janeway et al., Immunol. Rev. 107: 61-88 (1989); Berkoff et al., J. Immunol. 139: 3189-3194 (1988), and Kappler et al., Science 244: 811-813 (1989).

The "superantigens" mentioned supra, while generally stimulating T-cells as long as they possess a V.beta. element, are somewhat specific in terms of the particular form of the V.beta. moiety which is present on the stimulated T cell.

Rheumatoid arthritis ("RA") is an autoimmune disease characterized by chronic inflammation of multiple joints. Mononuclear cell infiltration of the synovial membrane can lead eventually to the destruction of articular cartilage and surrounding structures. Because of its high frequency and potentially severe nature, this disease is a major cause of chronic disability in adults. Although the pathogenesis of RA and other similar autoimmune diseases remains unknown, both genetic and environmental factors have been implicated. Several lines of evidence suggest that T cells specific for self-antigens may play a critical role in the initiation of these diseases. In the case of RA, the linkage of the disease to the DR4 and DRI alleles of the Class II genes of the major histocompatibility complex (MHC) and the finding of sometimes oligoclonal, activated CD4.sup.+ T cells in synovial fluid and tissue of affected joints (Stastny et al., New Engl. J. Med. 298: 869 (1976); Gibofsky et al., J. Exp. Med. 148: 1728 (1978); McMichael et al., Arth. Rheum. 20: 1037 (1977); Schiff et al., Ann. Rheum. Dis. 41: 403 (1982 ); Duquesnoy et al., Hum. Immunol. 10: 165 (1984); Legrand et al., Am. J. Hum. Genet. 36: 690 (1984); Gregerse et al., Arth. Rheum. 30: 1205 (1987); Nepon et. al., Arth. Rheum 32: 15 (1989); Burmester et al., Arth. Rheum. 24: 1370 (1981); Fox et al., J. Immunol. 128: 351 (1982); Hemler et al., J. Clin. Invest. 78: 696 (1986); Stamenkoic et al., Proc. Natl. Acad. Sci. U.S.A. 85: 1179 (1988) suggest the involvement of CD4.sup.+, .alpha..beta.TCR-bearing, Class II-restricted T cells in the disease. This view is supported by the finding that partial elimination or inhibition of T cells by a variety of techniques can lead to an amelioration of disease in certain patients (Paulus et al., Arth. Rheum. 20: 1249 (1977); Karsh et al., Arth. Rheum. 22: 1055 (1979); Kotzin et al., N. Eng. J. Med. 30: 969 (1989); Trentham et al., N. Eng. J. Med. 305: 976 (1989); Herzog et al., Lancet ii: 1461 (1987); Yocum et al., Ann. Int. Med. 109: 863 (1989).

Usually, potentially autoreactive T cells are deleted or inactivated by encounter with self-antigen during their development, before they can damage the individual (Kappler et. all, Cell 49: 273 (1987); Marrack et al., Nature 332: 840 (1988); Kappler et al., Nature 32: 35 (1988); MacDonald et al., Nature 332: 40 (1988); Pullen et al., Nature 35: 796 (1988); Bill et al., J. Exp. Med. 169: 1405 (1989); Kisielow et al., Nature 333: 742 (1988); Ramsdell et al. Science 246: 1038 (1989). In order to understand autoimmunity one must understand how self-reactive T cells escape these processes to become part of the mature T cell pool and what factors control whether these cells will remain quiescent or become activated to induce autoimmune disease. One suggested scenario has been that a self-antigen which is sequestered, at very low levels or presented on inappropriate cells may fail both to remove specific T cells during development and to activate these cells once they mature. Occasionally, however, microbial antigens cross-reactive with the self-antigens may lead to activation of these specific T cells. Once activated these cells may now recognize and chronically respond to the previously ignored self-antigen, leading to autoimmune disease. One difficulty with this suggestion is the low probability of a cross-reaction between two infrequently recognized antigens. However, recently a set of unusual microbial antigens, i.e., the superantigens have been identified (Kappler et al., supra; Marrack et al., supra; Kappler et al., Science 244: 811 (1989); Marrack et al., Science 248: 705 (1990); White et al., Cell 56: 27 (1989); Tomai et al., J. Exp. Med. 172: 359 (1990); Choi et al., J. Exp. Med. 172: 981 (190); Marrack et al., Nature 349: 524 (1991); Frankel et al., Nature 349: 526 (1991); Woodland et al., Nature 349: 529 (191); Dyson et al., Nature 349: 531 (1991). Because superantigens engage virtually all T cells whose TCR bears a particular V.beta. they can effect a much larger number of T cells than conventional antigenic peptides, which require target T cells to bear the correct versions of all the TCR variable elements (V.alpha., J.alpha., V.beta., D.beta., J.beta.). Superantigens are, therefore, statistically more likely than conventional microbial antigens to crossreact with self-antigens and it has been suggested that they may play a role in induction of autoimmunity (Marrack et al., Science 248: 705 (1990).

It has now been found that T cells carrying specific V.beta. elements are associated with different pathological conditions. In Ser. No. 437,370, it was shown that infection by a superantigen presenting organism could be detected and diagnosed by assaying for particular V.beta. elements in a T cell containing sample. In U.S. Pat. No. 488,353, this phenomenon was shown to be true for toxic shock related disorders as well.

It has also been found that specific V.beta. elements can be associated with autoimmune disease, including rheumatoid arthritis. It has been found, quite surprisingly, that T cell populations and subpopulations are implicated and/or involved in autoimmune disorders, and it is possible to identify these and to correlate their presence to particular autoimmune diseases. This, in part, is the subject of the invention.

It has also been found that, within T cell containing samples, evident of "clonality", a term which is explained infra, is also evident of an autoimmune disorder. The invention, in general, thus relates to a method for assaying for V.beta. elements in T cell containing body fluid samples. The levels obtained are compared to levels in normal individuals, and variation from the normal is an indication of an autoimmune condition.

The invention provides for a method for determining a T cell sample implicated in an autoimmune disease, by assaying a T cell containing body fluid sample to determine level of a V.beta. element characteristic of the pertinent T cell population. The level thus determined is compared to levels in a comparable T cell containing body fluid sample, and the levels are compared. Variation from the normal level is indicative of the pathological condition.

Also provided by the invention is a method for determining a pathological condition by determining clonality of a particular subpopulation of a T cell sample in a body fluid sample. "Clonality", as used herein, relates to the relationship or lack thereof between nucleic acid sequence coding of the .beta. chain of the TCR.

In a preferred embodiment, the V.beta. elements are assayed via polymerase chain reaction ("PCR"), although it is also possible to determined these via other methods, such as with antibodies specific for the V.beta. element.

The invention will be explained in the disclosure which follows.

FIG. 1 sets forth the distribution of T cells which display T cells showing V.beta.14.sup.+ phenotype in patients with rheumatoid arthritis, as well as in patients with other forms of arthritis, and non-arthritic donors.

In order to select subjects for the experiments which follow, patients from the rheumatology clinics of Fitzsimons Army Medical Center were chosen. Selection criteria included satisfaction of the criteria for classical or definite rheumatoid arthritis established by the American Rheumatism Association and the availability of synovial fluid from the subject. All patients had active inflammatory disease at the time that blood and synovial fluid samples were taken. The patients were classified via stage of disability and as to whether there were bone erosions and/or joint deformations found upon radiographic and physical examination. The classification "destructive" is used for these patients. "Stage 1 " refers to ability to perform all usual activities without handicap, "Stage 2" refers to ability to carry out normal activity, but with pain, "Stage 3" refers to an inability to accomplish some normal activities, usual occupation or self care; and "Stage 4" refers to patients who are largely or totally incapacitated or bed ridden.

Subjects were also taking any of a variety of drugs at the time of sampling, including standard "NSAIDs" (non-steroid anti-inflammatory drugs); prednisone, gold compounds administered intramuscularly, d-penicillinamine, methotrexate, azathioprine, and hydroxychloroquine. Patients were assayed to determine if rheumatoid arthritis factor was present, and if so, the titer. Finally, patient samples were also assayed to determine human leukocyte antigen ("HLA") Class-II type.

These data are summarized in Table 1, which follows, together with data from arthritic controls (i.e., patients with non-rheumatoid arthritis), and non-arthritic controls.

All but one of the rheumatoid arthritis patients expressed HLA-DR4, which is not surprising as this allele has been associated with rheumatoid arthritis previously.

Studies were undertaken to determine TCR-V.beta. presence and usage by individuals with rheumatoid arthritis. To do so, samples of mononuclear cells from peripheral blood and synovial fluid were isolated via Ficoll-Hypaque density gradient centrifugation. The cells were stimulated with anti-CD3 antibodies for three days, and were then cultured in the presence of interleukin-2 for 24 hours, following Kappler et al., Science 244: 811 (1989); Choi et al., J. Exp. Med. 172: 981 (1990), and Choi et al., Proc. Natl. Acad. Sci. U.S.A. 86: 8941 (1989). Tota) RNA was then isolated from these cells, following the above references. Great care was taken to prevent cross contamination, and none of the synovial fluid samples tested showed red blood cell contamination.

Two micrograms of total RNA were then used to synthesize first cDNA strains using reverse transcriptase and random hexonucleotides, following art recognized techniques. This reaction was stopped by heating at 95.degree. C., and the cDNA was then amplified via polymerase chain reaction (PCR) using a V.beta. specific oligomer, an oligomer from downstream .beta. chain constant region and two oligomers from the C.alpha. region. These primers are described in Choi et al., J. Exp. Med. 172: 981 (1990), and Choi et al., Proc. Natl. Acad. Sci. 86: 8941 (1981), both of Which are incorporated by reference as well as copending patent application Ser. No. 437,370 and Ser. No. 488,353, also incorporated by reference. Amount of cDNA and number of PCR cycles used were determined for each preparation to ensure that the amount of synthesized was proportional to the amount of V.beta. mRNA in the original sample. The amplified products were quantified using .sup.32 P end labeled 3' primers (.about.5.times.10.sup.5 cpm each), and were analyzed after separation of products on a 2% agarose gel. Percentages of T cells bearing each V.beta. element were obtained by normalizing cpms in V.beta. band to that in the C.alpha. band, which serves as internal control, and then transforming into a calculated percentage using a standard curve as per Choi et al., Proc. Natl. Acad. Sci. U.S.A. 86: 8941 (1981).

The V.beta. determinations were repeated at least twice, and usually four times. For several patient samples, i.e., those from RA-1, 3, 5 and 6, increasing numbers of cycles were carried out using V.beta.14 and control V.beta.2 specific primers to ensure that differences in percentages of V.beta.14 bearing cells were reproducible and that primer efficiencies were comparable. The results are presented in Table 2 as percentages.+-.standard deviation where PBL refers to peripheral blood lymphocytes and Sfld refers to synovial fluid.

To summarize these data, about 10% of PBLS bear V.beta.2, and from 4-13% bear V.beta.13.1, while less than 2% show V.beta.20. Differential expression is thus present. Some V.beta. expression varies from patient to patient. For example, V.beta.12 was found on less than 1% of PBL T cells in patients RA-2 and 5, but up to 7% in others. These variations were conserved from test to test and over time.

While synovial fluid TCR V.beta. repertoire tended to mirror the findings in PBLS, there were some "mismatches". Note, e.g., the higher percentages of V.beta.12, 13.1, 14 and 15 in the synovial fluid of patient RA-5 as compared to peripheral blood, while V.beta. 5.1, 8 and 10 exhibited the converse. This indicates that infiltration of synovial fluid by T cells in rheumatoid arthritis is not totally random or passive.

A key finding was the higher percentage of V.beta.14.sup.+ T cells in the synovial fluid of all seven patients as compared to the peripheral blood. This was due to strikingly low levels of V.beta.14.sup.+ T cells in the blood. The only time such a skewing did not occur was in patient RA-6, who was DR4.sup.- and did not show rheumatoid factor.

When two other individuals were studied in the same manner (RA8 and 9 of FIG. 1), the same skewing was found. The difference between the levels was highly significant using student's test analysis

The results set forth in Example 2 become more striking compared to experiments when patients with non-rheumatoid arthropathies were examined. Three patients (AC-1, 2 and 3 of Table 1), were subjected to the same sort of analysis carried out on the RA patients in Example 2. The results are presented in Table 3, which follows. The V.beta. pattern was heterogeneous, with synovial fluid distribution similar to that found in BBL. Most importantly, no enrichment of V.beta.14.sup.+ in synovial fluid was found.

Following the unexpected finding of the low levels of V.beta.14.sup.+ T cells in the peripheral blood of rheumatoid arthritis patients, experiments were carried out to determine if this phenomenon was associated with rheumatoid arthritis rather than HLA or MHC II subtype. To do this, the same type of assay was carried out, using PCR, on 9 rheumatoid arthritis patients, three arthritic controls, and eleven non-arthritic controls. Many of the non-arthritic patients also expressed HLA-DR4 MHC II subtype, as shown in Table 1 (i.e., NA 1, 4, 5, and 7-10). Five "RA" patients had less than 1% V.beta.14.sup.+ T cells in peripheral blood. In contrast, the lowest level in normal patients was 2% and it ranged up to 6%. Admittedly, patient RA-6 showed high levels of V.beta.14.sup.+ in peripheral blood, but as has been pointed out, supra, patient RA-6 showed significant differences from other rheumatoid patients. These results show that the observed phenomenon of low level V.beta.14.sup.+ presence in peripheral blood is attributable to rheumatoid arthritis, not expression of HLA-DR4.

Studies were carried out to determine if the V.beta.14.sup.+ T cells found in the synovial fluid of rheumatoid arthritis patients were oligoclonal. To do this, PCR generated .beta. chain fragments were cloned into an EcoRI-BamHI cut version of plasmid pTZ18R. Double stranded plasmid DNAs were prepared with acid phenol, following Weichert et al., in Editorial Comments (Cleveland: U.S. Biochemical Corp., 1989), page 5. A Sequence kit was then used to directly sequence these .beta. chains. As controls, V.beta. 13.2, which is closely related to V.beta.14, and V.beta.2 which is quite distantly related to V.beta.14 (Siu et al., J. Exp. Med. 164: 1600 (1986)) were used. For the comparison, V.beta.14.sup.+ cDNA clones from peripheral blood of one "RA" patient and one "NA" patient were sequenced, as well as one from synovial fluid of an "AC" patient.

Table 4, infra shows these results. In brief, a few clones dominate the V.beta.14.sup.+ T cell population of RA patients. Each patient showed that two clones accounted for 46-72% of the appropriate T cells. Dominant clonotypes were different in each patient, although restricted J.beta. usage was observed. Nearly all V.beta.14.sup.+ dominant clones used J.beta.1.1 or J.beta.2.3, while these clones accounted for only 39% of other RA synovial fluid V.beta.14.sup.+ clones, and only 14% of peripheral blood V.beta.14.sup.+ clones.

The V.beta.14.sup.+ .beta. chains from peripheral blood cells of RA and normal patients showed no evidence of clonality (none of 35 examined sequences were repeated). Thus, dominant clones do not represent an artifact of PCR amplification.

While there is some evidence for dominant T cell clones bearing other V.beta.s in synovial fluid, results are less diamatic than those seen with V.beta.14. For example, when patient RA-1 is studied, 7 of 17 sequences which included V.beta.13.2 had the same functional sequence, and three of 18 V.beta.2 clones from patient RA-2 were identical.

These data support the idea that synovial fluid T cells, taken from patients with arthropathies, are made up of a collection of expanded clones, presumably with some specificity for the disease, as well as a large number of non-specifically recruited cells. For RA patients, the V.beta.14 cells are particularly clonal, clearly suggesting a specific role for this T cell subtype in rheumatoid arthritis.

The foregoing data clearly show that it is possible to identify a T cell population which is implicated in an autoimmune disease by assaying for a V.beta. element characteristic of the T cell population involved, and comparing it to a normal sample. It will be understood that "population" as used herein refers to T cells which express a particular V.beta. element. T cells of a "V.beta.14" population, e.g., may express certain other antigens on their surface, but they will all express V.beta.14.

"Implicated" as used herein means that the T cell population is involved, either in whole or in part, with the development of the autoimmune condition. There may be other factors involved in a particular autoimmune pathology besides T cells, but T cells are always present.

In assaying the subject or patient, it is preferred to assay a T-cell containing body fluid sample because this is easier, but tissue samples can also be assayed, because T cells are found in tissues of patients with autoimmune disorders. "T-cell containing sample" therefore refers to any body fluid or tissue taken from the patient.

In the case of rheumatoid arthritis, the T cell population of relevance is V.beta.14, and the examples show how this population of cells was identified. In these examples, synovial fluid and blood were assayed. Synovial fluid was selected because this is found at the site of deterioration associated with rheumatoid arthritis. It will be understood that for different autoimmune disorders exhibiting different pathologies, different fluids or tissues will be examined. Non-limiting examples include systemic lupus erythematosis, a multisystem disease, which admits of examination of blood, skin, joints, arteries, muscle, pericardium and glomeruli tissues and fluids. Similarly, Hashimoto's thyroiditis, a disease involving thyroid inflammation calls for assay of thyroid tissue and fluid, whereas Addison's disease would call for analysis of adrenal samples. Multiple sclerosis suggests study of nerve tissue, spinal fluid, brain tissue and cerebral fluid, while autoimmune diabetes mellitus suggests analysis of pancreatic samples or islet of Langerhans samples.

The assaying of V.beta. elements has been exemplified by use of the polymerase chain reaction. This should not be considered to be the only way in which the V.beta. element of interest can be determined. The art is aware of antibodies, including monoclonal antibodies which specifically bind to and thereby identify individual V.beta. elements, e.g. Also, all methods for identifying or isolating particular proteins and peptides in a sample may be applied to the identification and quantification of V.beta. elements. These are well known to the skilled artisan, and need not be repeated here.

The identification of a particular V.beta. cell population with an autoimmune suggests a therapeutic method for treating the disease in question. It is known that, in autoimmune diseases T cells are involved in provoking and mediating immune responses. The identification of a specific V.beta. cell type as associated with an autoimmune disease means that the disease can be treated by administering an agent which specifically inhibits or leads to inhibition of the cell type in question. An example of such an agent is an antibody or monoclonal antibody, but other are possible. For example, one can mount an immune response against the T cell population itself by administering a sample of the V.beta. peptide with concomitant immune response. The immune response leads to identification, engagement and deletion of the T cell population causing the autoimmune disorder. This can also be done via administration of a so-called "superantigen", which engages the V.beta. element and leads to deletion of the cell presenting it. In some cases, this may be done, preferably, by administering the agent directly to the site of the disorder, so that the response can be localized and controlled. For rheumatoid arthritis, e.g., one may administer an anti-V.beta.14 antibody via injection at the site of joint deterioration.

One of the consequences of the data and experiments described herein is the ability to identify an agent associated with a particular autoimmune disease. It is known that a T cell response can be generated upon exposure of a mixed cell sample in vitro to an agent, and that a T cell response can be generated in an experimental animal. The invention permits one to identify a particular V.beta. element carrying T cell sample as being associated with an immune disorder. Once this is accomplished, various suspected agents can be tested to see if they provoke the same response or a parallel response either in vitro or in vivo. "Parallel response" refers to a situation where an experimental animal, such as a mouse, is used to test the agent. The murine T cell repertoire parallels the human system, but they are not identical. One would look for a response typical of murine arthritis, e.g., when studying the causative agent for rheumatoid arthritis in humans.

"Agent" as used herein refers to any material which provokes a T cell response. Superantigens have been described supra, and are included within this definition, as are environmental factors including various carcinogens and other chemicals, naturally occurring substances, bacterial pathogens and endotoxins, and so forth.

Another consequence of the invention is the ability to identify even more restricted populations of T cells via assaying for clonality. To elaborate, whereas a population of T-cells may all contain the same V.beta. element, this is only part of the .beta. chain of the T cell receptor. The data supra indicate that within the T cell population found in a sample, while there is variation, certain .beta. chains were predominant, clearly indicating that there was some process of selection leading to favoring of a particular T cell clone or clones. Where about 30% or more of a T cell population in a sample show identical .beta. chains, this is evidence of clonality, and of autoimmune pathology. "Identical" as used herein has the meaning ascribed thereto by those skilled in the art, and can include some minor variation as permitted within a clonal population.

It will also be clear that this invention includes a method for diagnosing an autoimmune disorder where this is necessary or desirable. Again, this involves identifying T cell populations by assaying samples containing T cells and comparing values obtained for a V.beta. element to normal values. Variation therefrom is indicative of an autoimmune disorder.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, it being recognized that various modifications are possible within the scope of the invention.