Lack of T cell oligoclonality in enzyme-digested synovial tissue and in synovial fluid in most patients with rheumatoid arthritis

Crystal structures of T cell receptor (beta) chains related to rheumatoid arthritis

The crystal structures of the Vbeta17+ beta chains of two human T cell receptors (TCRs), originally derived from the synovial fluid (SF4) and tissue (C5-1) of a patient with rheumatoid arthritis (RA), have been determined in native (SF4) and mutant (C5-1(F104-->Y/C187-->S)) forms, respectively. These TCR beta chains form homo-dimers in solution and in crystals. Structural comparison reveals that the main-chain conformations in the CDR regions of the C5-1 and SF4 Vbeta17 closely resemble those of a Vbeta17 JM22 in a bound form; however, the CDR3 region shows different conformations among these three Vbeta17 structures. At the side-chain level, conformational differences were observed at the CDR2 regions between our two ligand-free forms and the bound JM22 form. Other significant differences were observed at the Vbeta regions 8-12, 40-44, and 82-88 between C5-1/SF4 and JM22 Vbeta17, implying that there is considerable variability in the structures of very similar beta chains. Structural alignments also reveal a considerable variation in the Vbeta-Cbeta associations, and this may affect ligand recognition. The crystal structures also provide insights into the structure basis of T cell recognition of Mycoplasma arthritidis mitogen (MAM), a superantigen that may be implicated in the development of human RA. Structural comparisons of the Vbeta domains of known TCR structures indicate that there are significant similarities among Vbeta regions that are MAM-reactive, whereas there appear to be significant structural differences among those Vbeta regions that lack MAM-reactivity. It further reveals that CDR2 and framework region (FR) 3 are likely to account for the binding of TCR to MAM.

Simultaneous analysis of T cell clonality and cytokine production in rheumatoid arthritis using three-colour flow cytometry

In this study we examined the cytokine production by T cells and TCRVbeta subsets in peripheral blood (PB) and synovial fluid (SF) from six RA patients and PB from 10 normal subjects, using three-colour flow cytometry. In two RA subjects we assessed T cell clonality by RT PCR using TCRBV family-specific primers and analysed the CDR3 (complementarity determining region 3) length by GeneScan analysis. A high percentage of IFN-gamma- and IL-2- producing cells was observed among the PB T cells in both the RA patients and normal controls and among the SF T cells in RA patients. In contrast, the percentage of T cells producing IL-4 and IL-5 was small among PB T cells in both RA patients and normal controls and among SF T cells in RA patients. There was no significant difference in the production of IFN-gamma, IL-2 and IL-5 between the two compartments (PB and SF); however, there were significantly more IL-4-producing cells in SF. Molecular analysis revealed clonal expansions of four TCRBV families in SF of two of the RA patients studied: TCRBV6.7, TCRBV13.1 and TCRBV22 in one and TCRBV6.7, TCRBV21.3 and TCRBV22 in the second. These expansions demonstrated cytokine expression profiles that differed from total CD3+ cells, implying that T cell subsets bearing various TCR-Vbeta families may have the potential to modulate the immune response in RA patients.

Potential biologic agents for treating rheumatoid arthritis

The encouraging clinical results observed in trials using anti-TNF therapy clearly warrant further studies to determine whether TNF inhibitors are capable of modifying the destructive component of this disease in long-term follow-up studies as well as to assess the safety of long-term use (see the article by Keystone in this issue). It is also reasonable to propose that interfering with the cytokine cascade earlier in the course of disease may be of even greater therapeutic benefit. As the pathogenetic mechanisms in RA are more clearly defined, especially in early disease and in those individuals destined to develop severe disease, the potential of other biologic agents to specifically inhibit these critical pathways may provide better treatments for our patients. Many potential targets in the immune-mediated process of RA are currently being rigorously evaluated in clinical trials. Use of combinations of biologic therapies, perhaps in human patients with RA, should be of considerable interest in future trials.

T cells: pathogenic cells and therapeutic targets in rheumatoid arthritis

OBJECTIVES

To provide: 1) a brief review of current thought on the role of T cells in the pathogenesis of rheumatoid arthritis (RA); and 2) To provide an overview of RA therapies directed against T cells.

METHODS

The following papers in relevant American and European medical journals were reviewed. Those related to: the role of T cells in the pathogenesis of RA; to biological therapy directed against cell surface markers specific to T cell populations implicated in RA; and to treatment of RA with cyclosporin A and leflunomide, pharmacological agents known to interfere with the T cell response to antigens.

RESULTS

Although a variety of cell types are now recognized as contributors to the progressive joint destruction that is a hallmark of RA, T cell activation is still thought to be a central event in the initiation and progression of this disease. As a result, various therapeutic options directed against T cells have been developed. These include biological agents directed against specific populations of activated T cells and pharmacological agents that have specific T cell-modulatory actions.

CONCLUSIONS

Use of T cell-directed biological therapies for RA has been disappointing, as a result of both lack of efficacy and serious toxicity. Treatment of RA with pharmacological agents that interfere with antigen-driven T cell proliferation has been more successful.

Structural motifs in rheumatoid T-cell receptors

The linkage of rheumatoid arthritis (RA) to HLA-DR haplotypes, high levels of HLA-DR expression, and T-cell infiltration in the joints, indicate a central role for the interaction of T-cell receptors (TCR) with antigen (Ag) + major histocompatibility complex (MHC) complexes in pathogenesis. Receptor analysis in RA has uncovered a restricted heterogeneity of TCR transcripts, suggesting an antigen-driven response. We analyzed the sequence and structural features of RA-associated TCRs in light of the recently published TCR crystal structures. The surface-exposed residues of the third complementarity-determining region (CDR3s) showed preferential use of certain amino acid residues when sequences derived from synovial fluid or tissue were compared with those derived from peripheral blood, particularly for alpha chains. Sequence alignment of oligoclonal synovial TCR CDR3s revealed groupings with similar CDR3 lengths and amino acid compositions, which suggests shared antigen recognition. Given the limitations of analyzing TCR sequences without knowing their structures, we developed several in vivo-activated synovial-tissue Vbeta17 + RA T-cell clones. Two Vbeta17/V alpha7 clones with different CDR3 sequences were analyzed by molecular modeling. Although distinct topologic features were seen, a central patch of residues with similar chemical and geometric characteristics was present in both. Electrostatic maps revealed similar binding surfaces of both alpha domains and central patches, with differences in the beta domains. This suggests that an alpha-domain-focused binding trajectory would allow shared antigen recognition by these TCRs. These studies support recognition of a limited diversity of Ag + MHC complexes by synovial RA TCRs.

T cell receptor expression and differential proliferative responses by T cells specific to a myasthenogenic peptide

Myasthenia gravis (MG) is a T-cell-regulated autoimmune disease in which a pathological autoantibody response is mounted against the nicotinic acetylcholine receptor of the neuromuscular junction. Our laboratory previously identified a T cell epitope, p195-212, derived from the human acetylcholine receptor alpha subunit, which triggered PBL to proliferate from about 70% of MG patients tested. p195-212 was also found to be an immunodominant T cell epitope in SJL mice and a cryptic epitope in C3H.SW mice. Inoculation of naive SJL mice with cells from a p195-212-specific syngeneic T cell line caused MG-related autoimmune manifestations in those mice. In these studies we analyzed TCR alpha and beta chain sequences used by T cell lines and clones from both high- and low-responder mouse strains in response to p195-212. T cell lines generated from either strain expressed single TCR V beta gene segments (V beta 17 in SJL mice and V beta 8 in C3H.SW mice). By deleting V beta 17-expressing T cells in p195-212-immunized SJL mice we established a T cell line that expressed the V beta 6 gene product, suggesting that SJL mice are not limited to using a single V beta gene segment in response to p195-212. In addition, we found that N- and/or C-terminal-truncated peptides of p195-212, presented under the same culture conditions to different clones bearing the same TCR alpha beta chain, could elicit very different proliferative responses from the clones. Thus, even within a constrained system, factors other than TCR sequence contribute to the differential stimulation of T cell responses.

Heterogeneity of rearranged T cell receptor V alpha and V beta gene transcripts in synovial fluid T cells of HLA-B27 positive reactive arthritis patients

To analyze the T cell receptor (TCR) V-alpha/beta gene usage by synovial fluid (SF) and peripheral blood (PB) T cells of HLA-B27+ reactive arthritis (ReA) patients. The TCR V-alpha/beta gene usage was determined by the polymerase chain reaction on freshly isolated SF and PB mononuclear cells (MNC) of five HLA-B27+ ReA patients. A total of 30 TCR V alpha and 23 V beta (sub)family specific primers in combination with a C alpha or C beta specific primer, respectively, were used. In five patients most of the TCR V alpha and V beta gene segments expressed by PB T cells were also detected in the paired SF samples. Although one patient showed an increased expression of TCR V alpha2 in SF when compared to PB, the SF samples showed a heterogeneous TCR V-gene repertoire similar to PB. Although this study was limited to a small group of patients, the apparent lack of a restricted TCR V-gene repertoire in SF does not support the involvement of a single or limited number of T cell subsets in the disease process of HLA-B27+ ReA patients.

T cell receptor usage in autoimmune disease

Activated T-cells are believed to play a critical role in the pathogenesis of autoimmune disease. In experimental allergic encephalomyelitis (EAE), an animal model resembling human multiple sclerosis (MS), there is evidence that T cells reactive to myelin basic protein mediate an inflammatory response within the central nervous system leading to demyelination. Furthermore, encephalitogenic T cells express TCR with highly restricted V gene usage and consequently specific forms of immunotherapy directed against V gene products have been successful in preventing and treating EAE. These findings prompted studies into the analysis of TCR repertoire expression in human autoimmune diseases in an attempt to identify the TCR usage of autoreactive and potentially pathogenic T cells. However, this has proved difficult as the autoantigens that drive the T cell response in most human autoimmune disorders are unknown. This review examines the data that have accumulated over the past few years on TCR usage in human autoimmune diseases and is focused largely on rheumatoid arthritis and MS.

Large granular lymphocyte expansions in patients with Felty's syndrome: analysis using anti-T cell receptor V beta-specific monoclonal antibodies

Felty's syndrome (FS), the association of rheumatoid arthritis (RA) and idiopathic neutropenia, remains an unexplained phenomenon. HLA-DR4 is found in over 90% of cases. Patients with FS may have a T cell lymphocytosis of CD3+CD8+CD57+ large granular lymphocytes (LGL syndrome). In this study of 47 patients with FS, 19% had clear evidence for LGL expansions, while in total 42% had variable evidence for the LGL syndrome using currently available techniques. Of these T cell expansions, 76% were clonal, as demonstrated by Southern blotting and analysis with T cell receptor (TCR) beta chain constant region probes. This technique may fail to detect clonal populations in some patients. Cytofluorographic analysis using antibodies specific for TCR V beta chains identified patients with clonal LGL expansions with results comparable to those obtained with Southern blotting. No evidence for shared V beta usage among expansions from different patients was seen. The role of LGL in RA and FS is currently unclear, but this technique offers a practical and accessible means of identifying patients with LGL expansions, as a starting point for further investigation.

Therapeutic regulation of T cells in rheumatoid arthritis

TCR repertoire studies in RA have yielded conflicting data. These studies were initiated on the premise that clonal expression of T cells at the site of inflammation could serve as a target for immune therapies designed on the basis of the option to inactivate or eliminate the presumed pathogenic T cells. These analyses have demonstrated the existence of a highly diverse overall TCR repertoire on the basis of extensive usage of TCR V genes both in synovial fluid and tissue. However, clusters of RA patients can be recognized who share increased usage frequencies of defined TCR V genes among synovial fluid or synovial tissue lymphocytes. Subsequent analysis of the CDR3 regions among diverse overall TCR repertoires have revealed the presence of conserved amino acid sequences in the CDR3 regions of the variable portions of TCRs in T lymphocytes derived from the site of inflammation. These findings suggest that a selective, antigen-driven expansion of T lymphocytes is occurring in the inflamed joints. Parallel to the TCR-repertoire studies, we investigated whether vaccines prepared from synovial T cells could modulate T-cell reactivity. The studies were based on previous work on TCV in animals, revealing that attenuated non-specific T-cell lines could serve as a vaccine. The results obtained in 13 RA patients showed no clear indication for a cellular or humoral immune response. Our experience with TCV in RA patients showed that this technique is feasible and safe. We found some evidence for a modulated T-cell reactivity both in vivo and in vitro. These results show at least some immunomodulatory effect af T-cell vaccination, although the antigen specificity of the effect of this intervention remains to be shown. Because of the convincing studies in animals and MS patients, further studies in RA should focus on the effect of vaccination using vaccines prepared from disease-inducing cells. In this respect, determination of the CDR3 regions of synovial T cells could lead to the identification of those T cells that are relevant for the disease.

Oligoclonal activation of CD4+ T lymphocytes in posterior uveitis

Several lines of evidence support an important role for activated T lymphocytes in the perpetuation of autoimmune intraocular inflammatory disease (posterior uveitis). In this study peripheral blood lymphocytes (PBL) were examined by three-colour flow cytometry to assess the distribution of IL-2 receptors (IL-2R) among CD4+ and CD8+ T cell subsets in patients with active posterior uveitis and control subjects. Patients with uveitis (n = 70) showed a significant increase in PBL expressing the alpha-chain (Tac) of the IL-2R compared with controls (n = 28) (34.2% versus 29.6%) (P < 0.05). This increased Tac expression was present on both the CD4+ subset (25.7% versus 20.9%) (P < 0.05) and the CD8+ subset (2.5% versus 1.8%) (P < 0.05) of lymphocytes. We also examined whether the activated CD4+ PBL from uveitis patients (n = 30) showed a dominant pattern of T cell receptor (TCR) gene rearrangement, suggestive of an oligoclonal response to a small number of antigenic peptides. A significant increase in the usage of the V alpha 2.3 TCR family by activated but not by non-activated CD4+ PBL was detected in patients (3.9% versus 3.4%) (P < 0.05) compared with controls. There was evidence of oligoclonal activation of CD4+ PBL in 11/30 patients (36.7%) but in none of the controls (n = 10). However, different V alpha or V beta TCR families were selectively activated among and even within individual patients. The heterogeneity in TCR expression among patients with active intraocular inflammatory disease is discussed.

CDR3 sequence motifs shared by oligoclonal rheumatoid arthritis synovial T cells. Evidence for an antigen-driven response

T lymphocytes reactive with as yet undefined joint-localized foreign or autoantigens may be important in the pathogenesis of RA. Molecular studies demonstrating skewed T cell antigen receptor (TCR) variable gene usage and selective expansion of particular T cell clones within the synovial compartment support this view. Based on our recent study documenting selective expansion of V beta 17+ T cells in RA, we have pursued the identification of T cells relevant to the disease process, in an informative patient, by combining molecular analysis of freshly explanted RA synovial tissue V beta 17 TCR transcripts with in vitro expansion of V beta 17+ synovial tissue T cell clones. Peripheral blood V beta 17 cDNA transcripts proved heterogeneous. In contrast, two closely related sequences, not found in the peripheral blood, dominated synovial tissue V beta 17 transcripts, suggesting selective localization and oligoclonal expansion at the site of pathology. CD4+, V beta 17+ synovial tissue-derived T cell clones, isolated and grown in vitro, were found to express TCR beta chain transcripts homologous to the dominant V beta 17 synovial tissue sequences. One clone shares with a dominant synovial tissue sequence a conserved cluster of 4/5 amino acids (IGQ-N) in the highly diverse antigen binding CDR3 region, suggesting that the T cells from which these transcripts derive may recognize the same antigen. These findings have permitted a complete characterization of the alpha/beta TCR expressed by putatively pathogenic T cell clones in RA. Functional analysis suggests that the conserved CDR3 sequence may confer specificity for, or restriction by, the MHC class II antigen, DR4.

Increased frequency of V beta 17-positive T cells in patients with rheumatoid arthritis

OBJECTIVE

To identify the T lymphocytes that mediate disease in rheumatoid arthritis (RA).

METHODS

A panel of monoclonal antibodies reactive with T cell receptor (TCR) V beta gene products was used to analyze the RA T cell repertoire.

RESULTS

Of 5 TCR V beta gene products studied, only V beta 17-positive T cells were increased in peripheral blood and synovial fluid (SF) from RA patients, compared with controls (P < 0.01 and P = 0.0006, respectively). Thirty-one percent of the 49 RA SF samples and none of the 19 non-RA SF samples contained > 10% V beta 17-positive T cells. Activated (Tac-positive) T cells were enriched among V beta 17-positive synovial T cells.

CONCLUSION

The selective increase of V beta 17-positive T cells suggests a role for those T cells in the pathogenesis of RA.

V alpha gene usage in rheumatoid compared with osteoarthritic synovial tissue T cells

While many investigators have examined V gene usage by the clonotypic T-cell receptor (TCR) in rheumatoid arthritis (RA) joints, few have reported on arthritic controls. We compared TCR alpha-chain V gene usage in knee synovial tissue specimens from 9 RA and 5 osteoarthritis (OA) patients. There was no significant difference in the number of V gene families used in RA compared with OA synovium. However, there was an increased prevalence of V alpha 28, V alpha 10, V alpha 17, and V alpha 18 and under representation of V alpha 15 in RA compared with OA synovium. Of these, V alpha 28 was also recently described by us as being present in RA synovial tissue early in the course of disease. V alpha 28 associated J region usage, and N-regional diversity was surveyed in T-cell receptors from additional rheumatoid synovial tissue T-cell populations and normal peripheral blood. Oligoclonality was observed in 6/10 rheumatoid specimens either by direct sequencing or where three or more molecular clones were sequenced, compared with 0/5 normal PBMCs. The oligoclonal populations included 2/3 cell lines stimulated with interleukin-2 (IL-2) alone. Several novel J regions were observed, with some recurrent residues observed at N-region positions. These data indicate an increased prevalence of certain TCR V region families in RA versus OA synovium, and suggest an antigen-driven expansion of V alpha 28-expressing T cells in RA synovium.

T-cell receptor V-gene usage in synovial fluid lymphocytes of patients with chronic arthritis

In this study we analyzed the usage frequencies of the TCR V-gene segments by alpha beta+ T cells present in synovial fluid of 17 patients with chronic arthritis, including rheumatoid arthritis. The results of this study, obtained from semiquantitative PCR analyses, showed that in all patients most of the TCR V alpha- and V beta-gene segments could be detected both in fresh PBMCs and in fresh SFMCs. The relative frequencies of use of these V-region genes were variable between the different patients. Although there was some skewing of increased usage frequencies of particular TCR V alpha and V beta genes among SFMC-derived TCRs when compared with PBMCs, we could not correlate such increased TCR V-gene usage with the inflammation in the joints as a disease-specific marker.

Clonality of T lymphocytes expanded with IL-2 from rheumatoid arthritis peripheral blood, synovial fluid and synovial membrane

The association of rheumatoid arthritis (RA) with particular MHC class II genes suggests that autoantigen-specific T cell clones present in joints could be central to the pathogenesis of the disease. Previous investigations on the clonal diversity of T cells infiltrating the rheumatoid synovial membrane have yielded conflicting results. With the use of Southern blot analysis, we investigated the clonality of rheumatoid T cell lines expanded from peripheral blood, synovial fluid and synovial tissue. From peripheral blood lymphocyte (PBL) of RA patients and healthy normal controls, we also checked the consequences of two different culture conditions on the clonality of these cell lines. From control PBL, we found that in vitro non-specific expansion of non-clonal T cell populations does not create artefactual clonal selection. However, growing T cells in vitro with IL-2 seems to be able to lead to preferential expansion of cells bearing IL-2 receptor (IL-2R). We identified such in vivo activated IL-2-sensitive T cell clones frequently in RA synovial tissue (8/13) and more rarely in synovial fluid and peripheral blood (3/12). One patient presents the same T cell receptor gene rearrangements in synovial membrane of two affected joints. In RA synovial tissue, the frequency of these IL-2-responsive T cells is most prevalent among actively inflamed membranes removed early in the disease process. The role and the relevance to the disease of these IL-2-responsive T cells remain to be elucidated.

No restriction of intrathyroidal T cell receptor V alpha families in the thyroid of Graves' disease

Recently it has been reported that the intrathyroidal T cells in Graves' disease display restriction in V alpha T cell receptor (TcR) gene family usage, although this is not found with TcR V beta gene families in the same individuals. We have performed a qualitative analysis of TcR V alpha family usage in 12 patients with Graves' disease by reverse transcription and polymerase chain reaction (PCR) amplification of RNA extracted from isolated, unstimulated intrathyroidal lymphocytes and from snap-frozen whole thyroid specimens. No restriction was observed, with 10-15 V alpha gene families being amplified in all cases. The pattern of usage was similar to that in peripheral blood lymphocytes derived from normal subjects (n = 3) and from patients with Graves' disease (n = 3), as well as that present in the thyroids of patients with non-autoimmune toxic multinodular goitre (n = 4). These results indicated that there is no marked restriction of the unselected intrathyroidal T cell population in patients with Graves' disease who have been treated with antithyroid drugs.

Specific DNA amplification utilizing the polymerase chain reaction and random oligonucleotide primers: application to the analysis of antigen receptor variable regions

The polymerase chain reaction (PCR) allows rapid amplification of DNA of known sequence. In many situations, part of a genetic sequence is known, but adjacent sequences of interest are unknown. This is common in investigations of antigen receptor genes from B and T lymphocytes, which are composed of a constant region of known sequence and a variable region, for which the sequence may not be known. Herein is described a method to amplify DNA when sequence information is available for only one primer. This procedure utilizes a primer of known sequence in conjunction with a mixture of short random primers. Application of this method to the amplification of T-cell antigen receptor cDNA is described.

T-cell receptor V-gene usage in synovial fluid and synovial tissue from RA patients

The question of whether there is a preferential use of certain V genes in T cells entering an inflamed joint has hitherto been studied mainly using unfractionated cells from synovial fluid and tissue respectively, and no clear answer to the question has yet been provided. Concomitantly, evidence has been provided that the use of V genes may differ considerably between CD4+ and CD8+ T cells, and consequently that detection of biased V-gene expression within an inflammatory lesion may require separate analysis of the two T-cell subsets. In this paper we have therefore studied T-cell receptor V-gene expression in rheumatoid arthritis by means of double stainings of synovial fluid and blood for available anti-TCR monoclonal antibodies and antibodies to CD4 and CD8, respectively. Double stainings were also performed with anti-TCR antibodies and antibodies to activation markers HLA-DR and IL-2R. A certain bias towards the preferential use of certain V genes was seen particularly in the synovial fluid samples within both the CD4+ and CD8+ T-cell populations, but no uniform pattern was evident among the 35 patients investigated.

Restricted heterogeneity of T cell receptor transcripts in rheumatoid synovium

RA is characterized by massive proliferation of synovial tissue, accompanying infiltration of the tissue with CD4+ T lymphocytes, and a genetic linkage to the MHC antigen HLA-DR4. Since T cells are restricted by class II MHC molecules such as DR4, this suggests a direct role for these CD4+ cells in pathogenesis. To investigate T cell receptor (TCR) usage in RA, we used oligonucleotide primers specific for each of the major alpha and beta TCR subfamilies to amplify cDNA derived from whole synovium or synovial tissue T cell lines in a family-specific manner. Detection of amplified DNA was facilitated by utilizing oligonucleotide probes derived from the constant regions of the TCRs. The TCR repertoire present in the synovial T cell lines was quite heterogeneous, with an average of 15 alpha chains and 15.8 beta chains detected. When synovial tissue was analyzed, the predominant TCR subfamilies detected tended to be more restricted, with an average of 4.6 alpha chains and 8.6 beta chains detected. This compared with an average of six alpha chains and 12 beta chains in nonrheumatoid synovial samples. The average percentage of synovia positive per TCR beta family was significantly lower for RA versus non-RA specimens (46.1 vs 65.6%, P = 0.034). These findings indicate that while a polyclonal population of T cells is present in RA synovium, the predominant patterns of TCR transcript expression may be somewhat more restricted, suggesting that TCR-based therapy of RA is possible.

T-cell receptor beta-chain gene rearrangements of T-cell populations expanded from multiple sites of synovial tissue obtained from a patient with rheumatoid arthritis

In this study T-cell receptor (TcR) beta-chain gene rearrangements of T-cell lines prepared from multiple sites (n = 92) of synovial tissue derived from both knees of a patient with rheumatoid arthritis were analysed. In the majority of T-cell lines, dominant TcR beta-chain gene rearrangements were detected, involving C beta 1 as well as C beta 2. The dominant rearrangement patterns of T-cell lines from different tissue fragments showed significant variability, but some of the DNA restriction fragments were shared by T-cell lines from multiple sites in both knees. The latter observation suggests that identical T-cell clones may be present at different sites in the synovial tissue and in different joints. However, since many T-cell lines yielded different rearrangement patterns, these data also indicate considerable heterogeneity of T cells in the joints. Apart from theoretical implications, this TcR heterogeneity of T cells within an individual patient also has practical consequences for studies on synovial T cells obtained by biopsy.

Immune responses to 18.6 and 30-kDa mycobacterial antigens in rheumatoid patients, and V beta usage by specific synovial T-cell lines and fresh T cells

We have investigated both the humoral and the cellular immune responses of patients with juvenile rheumatoid arthritis (JRA) and rheumatoid arthritis (RA) to mycobacterial antigens. The JRA group was not Bacillus Calmette Guerin (BCG) vaccinated whilst the majority of the RA group was. As determined by immunoblotting, 79% of sera from patients with JRA reacted mainly with a 18.6-kDa protein (P18.6), whilst 70% of sera from patients with RA reacted mainly with a 30-kDa protein (P30) of BCG, M. tuberculosis and M. kansasii. In contrast, only a moderate proportion of the control sera (25% of adult and 20% of children) showed reactivity to P30, and none of the samples had significant reactivity with the P18.6 antigen. Furthermore, T-cell proliferation to the P18.6 and P30 antigens was detected in the majority of JRA and RA patients, and was nearly always higher in synovial fluid (SF) than in the peripheral blood (PB). We also investigated the usage of V beta family genes in P18.6 and P30 antigen-specific T-cell lines established from the SF of one patient with active RA. We showed that V beta 2, -4, -5, -6, -7, -14, -17, -18 and V beta 19 were over-represented compared with other known V beta families. We also noted that the proportion of V beta 14 was higher in freshly isolated SF mononuclear cells compared with the blood in this patient and in 2 out of 4 other RA patients examined. Other V beta families such as V beta 6, V beta 8, V beta 16, V beta 18 and V beta 19 were also over-represented in the SF compared with the blood in some patients. Taken together our results provide more information concerning the role of mycobacterial antigens in RA and suggest that there may be an in vivo clonal expansion of T lymphocytes in the synovium.

Analysis of T cell receptor V alpha and V beta gene usage in synovia of patients with rheumatoid arthritis

T cells are thought to play a fundamental role in the pathogenesis of rheumatoid arthritis (RA). Activated T cells expressing alpha/beta T cell receptor (Tcr) infiltrate the rheumatoid synovium and could potentially initiate a local inflammatory response directed against joint constituents. A Tcr repertoire with restricted heterogeneity may reflect a selective expansion of T cells reactive to a few antigenic determinants within the synovium. To determine whether predominant V alpha and/or V beta gene usage of the expressed alpha/beta Tcr repertoire is a feature of synovial T cells in patients with RA, the polymerase chain reaction (PCR) was used to amplify Tcr-alpha and Tcr-beta chain transcripts. The peripheral blood and synovia of five patients with adult RA were examined and no evidence of preferential use of 19 Tcr V alpha gene families was found. Similarly, most of the 18 Tcr V beta gene families could be detected in RA synovia although there were quantitative differences in Tcr V beta gene expression when compared to peripheral blood. This report shows that when the extremely sensitive assay of oligonucleotide hybridization of PCR amplified Tcr transcripts is used, permitting identification of specific V gene families, the alpha/beta Tcr repertoire in the rheumatoid synovium is more diverse than was previously thought. Therefore, in patients with RA of long duration, the synovial T cell response is most likely to be polyclonal.