Objective: To investigate the development and T cell receptor (TCR) usage of CD8+, CD57+ T cells in rheumatoid arthritis (RA) patients.
Methods: Three-color flow cytometry using monoclonal antibodies (MAb) to CD8, CD57 and different TCR V beta gene products.
Results: The proportion of CD8+ T cells expressing CD57 (CD57/CD8) was significantly higher in RA patients compared with age-matched controls. Expanded TCR V beta populations were more frequent, and were found in both RA patient-derived CD8high+ (CD57+) and CD8+, CD57- populations. TCR V beta 5+ and TCR V beta 13+ expansions were present at high frequency (5 of 26 and 7 of 26, respectively). TCR V beta expansions in CD8high+ (CD57+) lymphocytes from RA patients were significantly larger than those in age-matched controls (expansion index 2.38 +/- 0.28, n = 41 and 1.63 +/- 0.09, n = 32, respectively), and were stable over time.
Conclusion: RA leads to an increase in the frequency of expanded CD8+ T cell subsets expressing selected TCR, due to expansion of TCR V beta + populations in CD8high+ (CD57+) T cells. Their restricted TCR usage suggests potential specificity for RA antigens and, therefore, a potential role in the pathogenesis of RA.