Expression of HLA-DR, DQ and DP antigens and interleukin-2 receptor on synovial fluid T lymphocyte subsets in rheumatoid arthritis: evidence for "frustrated" activation.

Synovial fluid and peripheral blood T lymphocytes were examined from 10 patients with rheumatoid arthritis and 2 controls. T lymphocytes from inflammatory fluids were activated as shown by their increased size and expression of class II MHC antigens. Of the T cells, 60% were DR positive, 19% DP positive and 29% DQ positive. More Leu 2a than Leu 3a cells were HLA-DR positive. In contrast, few T cells expressed Tac. We conclude that T cell activation is taking place but is incomplete or "frustrated".