The nonspecific inhibitory effect of synovial tissue extracts on leucocyte migration in vitro

The leucocyte migration inhibition test (LMT) has been used to search for specific antigens in rheumatoid synovial tissue. Synovial samples were collected from 20 patients with rheumatoid arthritis, from 1 patient with ankylosing spondylitis, and from 1 patient with pigmented villonodular synovitis. Inhibitory material was obtained from all 21 synovia with inflammatory disease but not from the noninflammatory synovium. The tissue extracts generally caused nonspecific migration inhibition when tested against a total of 157 pairs of rheumatoid and control leucocytes. However, occasional samples did induce migration inhibition restricted to either rheumatoid or control cells. The inhibitory factor was shown to be membrane associated and of high molecular weight (greater than 10(6) daltons). The results of this extensive study do not support the conclusions drawn from earlier reports based on smaller numbers of experiments. No evidence was obtained for the existence of specific antigenic material associated with the synovial membrane in rheumatoid arthritis.