Treatment of the seronegative spondyloarthropathies with sulfasalazine.

Three patients with reactive arthritis and 2 with ankylosing spondylitis resistant to therapy with nonsteroidal antiinflammatory drugs were treated with enteric coated sulfasalazine in an open trial. Significant toxicity was not observed; 1 patient discontinued sulfasalazine because of gastrointestinal symptoms. As a group, statistically significant improvement was observed in 50 foot walk time, morning stiffness, and hemoglobin concentration. One patient went into complete clinical remission, 2 improved, 1 showed no change, and 1 worsened. Asymptomatic colonic inflammation was found in each of 4 patients examined before beginning therapy. Changes in bowel pathology did not parallel changes in joint symptoms. Sulfasalazine may be a safe and useful therapeutic modality in patients with chronic reactive arthritis or ankylosing spondylitis.

In vitro immunomodulatory effects of sulfasalazine and its metabolites.

We assessed the in vitro effects of sulfasalazine and its 2 main metabolites, sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA) on functional aspects of peripheral blood lymphocytes (PBM) of normal controls and patients with rheumatoid arthritis (RA). Sulfasalazine, but not its 2 main metabolites, inhibited mitogen induced proliferative responses of PMB at high drug concentrations (100 micrograms/ml). Similar results were obtained with purified B lymphocytes. Sulfasalazine depressed, in a dose dependent manner, pokeweed mitogen induced Ig synthesis by PBM of normals and patients with RA. Moreover, synthesis of IgM rheumatoid factor was depressed to a greater degree than total IgM at low sulfasalazine concentrations (10-25 micrograms/ml). Both SP and 5-ASA were not inhibitory at the concentrations tested. Experiments with purified lymphocyte subpopulations indicated that sulfasalazine exerted its major inhibitory activity on the B lymphocyte. These studies indicate that sulfasalazine, but not its 2 main metabolites, has immunomodulatory characteristics which may be related to its therapeutic activity in RA.