TCRB clonotypes are present in CD4+ T cell populations prepared directly from rheumatoid synovium

Study of the T-cell receptor repertoire by CDR3 spectratyping

The T-cell receptor (TCR) is the key player within the so called immunological synapse and the analysis of its repertoire offers a picture of both versatility and wideness of the whole immune T-cell compartment. Among the different approaches applied to its study the so-called spectratyping identifies the pattern of the third complementarity determining region (CDR3) length distribution in each one of the beta variable (TRBV) subfamilies encoded by the corresponding genes. This technique consists in a CDR3 fragment analysis through capillary electrophoresis, performed after cell separation, RNA extraction and reverse transcriptase PCR. This review will run through the most relevant studies which have tried to dissect the TCR repertoire usage in patients with different immune-mediated and infective diseases as well as solid or haematologic malignancies.

Skewed T-cell receptor BV14 and BV16 expression and shared CDR3 sequence and common sequence motifs in synovial T cells of rheumatoid arthritis

T-lymphocytes play an important role in rheumatoid arthritis (RA). In this study, we evaluated the hypothesis that common T-cell receptor (TCR) structural features may exist among infiltrating T cells of different RA patients, if the TCR repertoire is shaped by interaction with common self or microbial antigens in the context of susceptible HLA genes in RA. Synovial lesion tissue (ST), synovial fluid (SF) and blood specimens from RA patients and controls were analyzed for TCR V gene repertoire by real-time PCR. There was highly skewed BV14 and BV16 usage in synovial T cells of RA as opposed to those of controls, which was accompanied with a trend for correlation between skewed BV16 and DRB1(*)0405. Immunoscope analysis of the V-D-J region of ST-derived T cells demonstrated oligoclonal and polyclonal expansion of BV14(+) and BV16(+) T cells. Detailed characterization using specific BV and BJ primers further revealed common clonotypes combining the same BV14/BV16, BJ and CDR3 length. DNA cloning and sequence analysis of the clonotypes confirmed identical CDR3 sequences and common CDR3 sequence motifs among different RA patients. The findings are important in the understanding of BV gene skewing and CDR3 structural characteristics among synovial infiltrating T cells of RA.

Diagnostic role of tests for T cell receptor (TCR) genes

Rapid advances in molecular biological techniques have made it possible to study disease pathogenesis at a genomic level. T cell receptor (TCR) gene rearrangement is an important event in T cell ontogeny that enables T cells to recognise antigens specifically, and any dysregulation in this complex yet highly regulated process may result in disease. Using techniques such as Southern blot hybridisation, polymerase chain reaction, and flow cytometry it has been possible to characterise T cell proliferations in malignancy and in diseases where T cells have been implicated in the pathogenesis. The main aim of this article is to discuss briefly the process of TCR gene rearrangement and highlight the disorders in which expansions or clonal proliferations of T cells have been recognised. It will also describe various methods that are currently used to study T cell populations in body fluids and tissue, their diagnostic role, and current limitations of the methodology.

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.

Oligoclonal and polyclonal CD4 and CD8 lymphocytes in aplastic anemia and paroxysmal nocturnal hemoglobinuria measured by V beta CDR3 spectratyping and flow cytometry

We have hypothesized that in aplastic anemia (AA) the presence of antigen-specific T cells is reflected by their contribution to the expansion of a particular variable beta chain (V beta) subfamily and also by clonal CDR3 skewing. To determine the role of disease-specific "signature" T-cell clones in AA, we studied preferential V beta usage by flow cytometry and analyzed V beta-CDR3 regions for the presence of oligoclonality. We first established the contribution of each V beta family to the total CD4(+) and CD8(+) lymphocyte pool; in AA and paroxysmal nocturnal hemoglobinuria, a seemingly random overrepresentation of different V beta families was observed. On average, we found expansion in 3 (of 22 examined) V beta families per patient. When the contribution of individual V beta families to the effector pool was examined, more striking V beta skewing was found. V beta-CDR3 size distribution was analyzed for the expanded V beta families in isolated CD4(+) and CD8(+) populations; underrepresented V beta families displayed more pronounced CDR3 skewing. Expanded CD4(+)V beta subfamilies showed mostly a polyclonal CDR3 size distribution with only 38% of skewing in expanded V beta families. In contrast, within overrepresented CD8(+)V beta types, marked CDR3 skewing (82%) was seen, consistent with nonrandom expansion of specific CD8(+) T-cell clones. No preferential expansion of particular V beta families was observed, in relation to HLA-type. In patients examined after immunosuppressive therapy, an abnormal V beta-distribution pattern was retained, but the degree of expansion of individual V beta was lower. As V beta skewing may correlate with relative V beta size, oligoclonality in combination with numerical V beta expansion can be applied to recognition of disease-specific T-cell receptors.

Changes in T-cell receptor VB repertoire in aplastic anemia: effects of different immunosuppressive regimens

We studied the degree and the pattern of skewing of the variable region of beta-chain (VB) T-cell receptor (TCR) repertoire in aplastic anemia (AA) at initial presentation and after immunosuppression using a high-resolution analysis of the TCR VB complementarity-determining region 3 (CDR3). Age-matched healthy individuals and multitransfused patients with non-immune-mediated hematologic diseases were used as controls. In newly diagnosed AA, the average frequency of CDR3 size distribution deviation indicative of oligoclonal T-cell proliferation was increased (44% +/- 33% vs 9% +/- 9%; P =.0001); AA patients with human leukocyte antigen (HLA)-DR2 and those with expanded paroxysmal nocturnal hemoglobinuria clones showed more skewed VB repertoires. Nonrandom oligoclonal patterns were found for VB6, VB14-16, VB21, VB23, and VB24 subfamilies in more than 50%, and for VB15, VB21, and VB24 in more than 70% of AA patients with HLA-DR2. Patients received immunosuppression with antithymocyte globulin (ATG)/cyclosporine (CsA) or cyclophosphamide (CTX) with CsA in combination, and their VB repertoire was reanalyzed after treatment. Whereas no significant change in the degree of VB skewing in patients who had received ATG was seen, patients treated with CTX showed a much higher extent of oligoclonality within all VB families, consistent with a profound and long-lasting contraction of the T-cell repertoire. VB analysis did not correlate with the lymphocyte count prior to lymphocytotoxic therapy; however, after therapy the degree of VB skewing was highly reflective of the decrease in lymphocyte numbers, suggesting iatrogenic gaps in the VB repertoire rather than the emergence of clonal dominance. Our data indicate that multiple specific clones mediate the immune process in AA.

Divergence in the degree of clonal expansions in inflammatory T cell subpopulations mirrors HLA-associated risk alleles in genetically and clinically distinct subtypes of childhood arthritis

Clinically distinct forms of childhood arthritis are associated with different risk alleles of polymorphic loci within the MHC, which code for the antigen-presenting class I or class II molecules. We have compared the TCR diversity of synovial T cells from children with enthesitis-related (HLA-B27(+)) arthritis and oligoarticular arthritis (with class II MHC risk allele associations) in parallel with peripheral blood T cells from each child, using a high-resolution heteroduplex TCR analysis. We demonstrate that multiple clonal T cell expansions are present and persistent within the joint in both groups, but that there is disease-specific divergence in the dominant T cell subset containing these expansions. Thus, the largest clonotypes within the inflamed joints of children with class II-associated arthritis are within the CD4(+) synovial T cell population, while the dominant clones from children with enthesitis-related arthritis (associated with a class I allele) are within the CD8(+) synovial T cell population. These data provide powerful data to support the concept that recognition of MHC-peptide complexes by T cells plays a role in the pathogenesis of juvenile arthritis.

Psoriatic arthritis joint fluids are characterized by CD8 and CD4 T cell clonal expansions appear antigen driven

The CD8 alphabetaT cell receptor repertoire in joint fluid of individuals with active psoriatic arthritis contained an average of 32 major oligoclonal expansions in many variable genes of the TCR beta chain (BV) families, as shown by beta-chain CDR3 length analysis. Interestingly, a small number of oligoclonal expansions were shared between simultaneous samples of joint fluid and blood; however, most expansions found in joint fluid were not identifiable in blood emphasizing the immunologic specificity of the clonal events for the inflamed joint at a given point of time. The CD4 T cell joint fluid repertoire contained fewer and smaller oligoclonal expansions also largely restricted to the joint, suggesting that CD4 T cells participate perhaps by interacting cognitively to generate the CD8 clones. The inferred amino acid sequence of a single CD8 oligoclonal expansion revealed that they usually are composed of one or a few structurally related clones at the amino acid sequence level with beta-chains that encode identical or highly homologous CDR3 motifs. These were not shared among patients. Moreover, several clones that encoded the same amino acid sequence were found to be structurally distinct at the nucleotide level, strongly implying clonal selection and expansion is operating at the level of specific TCR-peptide interactions. The findings support a model of psoriatic arthritis inflammation involving extensive and selective Ag, likely autoantigen, driven intra-articular CD4, and CD8 T cell clonal expansions.

Skewed T-cell receptor variable gene usage in the synovium of early and chronic rheumatoid arthritis patients and persistence of clonally expanded T cells in a chronic patient

OBJECTIVE

Autoreactive T cells may contribute to the pathogenesis of rheumatoid arthritis (RA). We studied the T-cell receptor (TCR) V-gene repertoire in the blood and synovium of early and chronic RA patients using polymerase chain reaction-enzyme-linked immunosorbent assay to evaluate possible differences between these patient groups.

RESULTS

Over-represented TCR V genes were observed in the synovium, but not in the blood of all RA patients (n = 38). The number of over-represented V genes was higher in the synovium of chronic RA patients (n = 31) than in that of early RA patients (n = 7). The V-gene profile was different among patients, and similar in the two knees for patients with bilateral synovitis (n = 5). The clonal composition of over-represented TCR BV genes in a patient with early RA and a patient with chronic RA was further studied by CDR3 region sequence analysis. A high level of clonal diversity was found in the joints and the blood of the early RA patient, suggesting a polyclonal T-cell expansion. In the chronic RA patient, predominant clonal expansions were observed in the blood and synovium, and some expanded clones were still present 2 yr later.

CONCLUSIONS

The observation of similar T-cell populations in both joints in patients with bilateral synovitis and the persistence of clonally expanded T cells for more than 2 yr in the joints of a chronic RA patient may indicate a pathogenic role for these cells in the disease process.