Augmented Numbers of HLA‐DR‐Positive T Lymphocytes in the Synovial Fluid and Synovial Tissue of Patients with Rheumatoid Arthritis and Juvenile Rheumatoid Arthritis

Abstract

Twenty-40% of T-cells from synovial fluid and synovial tissue and 3-11% of the peripheral blood T lymphocytes from patients with rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) expressed HLA-DR antigens as detected by monoclonal anti-HLA-DR antibodies in direct immunofluorescence. Synovial fluid and synovial tissue T lymphocytes had a stimulating capacity comparable to that of non-T cells in the allogeneic primary mixed lymphocyte reaction (MLR). The MLR was inhibited by monoclonal anti-HLA-DR antibodies. This is apparently the 1st report on in vivo-activated T lymphocytes as stimulator cells in MLR. T-cells from synovial fluid and synovial tissue are probably locally activated by stimuli so far unidentified.