INCREASED USAGE OF V(BETA)2 AND V(BETA)6 IN RHEUMATOID SYNOVIAL-FLUID T-CELLS

Objective. To determine if the T cell antigen receptor V-beta usage of unstimulated rheumatoid arthritis (RA) synovial fluid (SF) T cells is biased compared with those in peripheral blood (PB). Methods. Freshly isolated, matched synovial fluid and peripheral blood T cells were analyzed for V(b)eta gene expression using quantitative polymerase chain reaction (PCR) methods. Ten synovial fluid samples from the knees of 7 patients with RA were studied. The PCR assay used 26 V-beta primers with a constant region C-beta primer, and 2 C-alpha primers that co-amplified a product that served as an internal standard. Cycle number and complementary DNA content were controlled to ensure the linear accumulation of PCR products. Labeled products were separated on 10% polyacrylamide gels and counted with a Betascope blot analyzer. Results. There were consistent differences between the V-beta gene usage of SF and PB T cells directly isolated from patients with RA, regardless of HLA-DR haplotype. In all synovial specimens, V(beta)2 was increased relative to the peripheral blood, while V(beta)13.1 and V(beta)13.2 were decreased. V(beta)6 and V(beta)21 were increased in 9 of the 10 synovial samples. Analyses of bilateral SF specimens from 2 subjects and serial specimens from the same knee of 1 subject revealed virtually identical patterns in each patient. The SF V-beta bias was not solely due to differences in the proportion of CD4+ and CD8+ cells, because the CD4:CD8 ratios in SF and PB were similar. However, V-beta gene usage of separated CD4+ and CD8+ synovial T cells showed that V(beta)2 and V(beta)6 were more highly expressed on CD4 cells. Conclusion. Freshly isolated synovial T cells from inflamed (not end-stage) knees of patients with RA have a remarkably consistent biased V(b)eta gene usage compared with PB T cells. V(beta)2 and V(beta)6 are uniformly increased, and this increase is primarily in CD4+ T cells. The same V-beta bias in the SF T cells of several RA patients suggests that shared antigens may be stimulating the T cell response.