Concanavalin A-induced suppressor cell activity and in vitro immunoglobulin secretion in rheumatoid arthritis: correlation with clinical and immunological parameters.

Concanavalin A-induced suppressor cell activity was found moderately but significantly (P less than 0.05) decreased in RA patients treated with nonsteroidal antiinflammatory drugs (31 +/- 7% suppression) as compared to patients on remission-inducing drugs, such as gold, penicillamine, or chloroquine (51 +/- 6%) or to healthy individuals (50 +/- 6%). Also, lymphocytes from patients with antibodies to collagen mediated lower suppression (33 +/- 7%) than lymphocytes from patients without evidence for these autoantibodies (61 +/- 11%). No significant difference between patients and controls or between individual groups of patients were observed in regard to IgM and IgG secretion induced by pokeweed mitogen. Thus, although no indication for a severe derangement of regulatory cells in peripheral blood of RA patients could be observed in this study, a slight deficiency of ConA-inducible suppressor cells that may be reverted by remission-inducing drugs seems to be present in RA.