T lymphocyte subpopulations defined by monoclonal antibodies in synovial fluid of patients with rheumatic disease.

The proportion of T lymphocytes reacting with monoclonal antibodies to suppressor or helper T cell subsets and the proportion of T lymphocytes with Fc receptors for IgG or IgM were determined in synovial fluid and blood of 16 patients with rheumatic diseases including rheumatoid arthritis (RA), psoriatic arthritis, ankylosing spondylitis and juvenile rheumatoid arthritis. The percentage of T cells reacting with monoclonal antibodies (Leu 2a or OKT 8) directed at the suppressor/cytotoxic T cell subpopulation, was significantly higher in synovial fluid than in blood of patients or healthy donors. Monoclonal antibodies (Leu 3a or OKT 4) with specificity for the helper T cell subpopulation, reacted with a lower percentage of synovial T cells than of blood T cells of patients or controls. This distribution pattern was found in patients with RA as well as in the other patients with chronic arthritis. The percentage of T cells with Fc-IgG receptors (TG cells) was much lower in synovial fluid than in blood of patients or controls. Thus, in synovial fluid the percentage of T cells reacting with monoclonal antibody to the suppressor/cytotoxic cell subset was fairly high (mean 45%) whereas the proportion of TG cells, considered to represent suppressor cells, was low (mean 4%).