T lymphocyte subpopulations in synovial fluid of patients with rheumatic disease.

The proportion of T lymphocytes with receptors for the Fc portion of IgG (TG cells) of IgM (TM cells) was determined in synovial fluid and blood of 16 patients with various rheumatic diseases including rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. The percentage of TG cells was low in all synovial fluid samples, whereas in the patients' blood the percentage was higher than or equal to the level found in the blood of healthy subjects. Eight patients also had a lower level of TM cells in synovial fluid as compared to the percentage found in the blood of healthy donors. In the patients' blood the percentage of TM cells was usually within the normal range. Thus the proportion of T cells lacking either receptor (Tnull cells) was higher in synovial fluid than in blood. This pattern of low TG cell and high Tnull cell percentages was found in the synovial fluid of patients with various rheumatic diseases and thus seems to be a general feature of chronic inflammatory joint exudates.