Gamma/delta T cells and their subpopulations in blood and synovial fluid from rheumatoid arthritis and spondyloarthritis.

T cell receptor (TCR) gamma/delta bearing lymphocytes in peripheral blood and synovial fluid from rheumatoid arthritis (RA) and seronegative spondyloarthritides (SSA) were evaluated by means of double label immunofluorescence and cytofluorographic analysis. Three monoclonal antibodies (MAb) were used. TCR delta-1 against a common delta chain epitope, BB3 directed against the T cell subset whose TCR is encoded by the V delta 2 gene, and A13 directed against the V delta 1 subset. Peripheral blood T gamma delta cells were significantly reduced compared to normal control blood in RA patients who had joint effusion but not in other RA patients. The decrease of T gamma delta in the RA PB was mainly confined to the A13+ subset. In RA synovial fluid (RA SF) T gamma delta cells were significantly increased compared to paired but not normal peripheral blood, the most significant being the increase of A13+ cells. In contrast, in patients with SSA, no change in T gamma delta cells was observed on PB or SF. These data suggest that in RA, but not SSA, T gamma delta cells migrate from PB to inflamed synovium and thus may be involved in the pathogenesis of RA.