Differences in the distribution of synovial T lymphocyte subpopulations between patients with acute and chronic...

T lymphocyte subpopulations were determined by monoclonal antibodies Leu 2 (suppressor/cytotoxic subset) and Leu 3 (helper/inducer subset) in synovial fluid (SF) and blood of 9 patients with acute non-septic synovitis (duration less than 1 month), 28 patients with chronic synovitis (16 with rheumatoid arthritis (RA), 7 with ankylosing spondylitis, 4 with psoriatic arthritis and one with juvenile rheumatoid arthritis) and 37 age- and sex-matched healthy controls. The patients with acute synovitis had a significantly higher percentage of Leu 3+ cells and a significantly lower percentage of Leu 2+ cells in SF than had patients with RA or other forms of chronic synovitis. In patients with acute synovitis the ratio of Leu 3+ to Leu 2+ cells was significantly higher in SF (4.0) than in blood (1.9) whereas in patients with RA the ratio was significantly lower in SF (1.1) than in blood (2.7). Patients with other forms of chronic synovitis also had a lower Leu 3/Leu 2 ratio in SF (1.1) than in blood (1.9). Two patients with acute synovitis who were retested after 10 days and 10 months respectively (the latter patient having developed definite RA) showed a decrease of the synovial Leu 3/Leu 2 ratio. Thus it appears that the distribution of T lymphocyte subsets in SF was related to the duration of the synovitis.