Circulating levels of interleukin 10 and other cytokines in rheumatoid arthritis treated with cyclosporin A or combination therapy.

Objective. To assess longitudinally over a 12 month period circulating serum levels of interleukin 10 (IL-10) and cytokines IL-3, IL-4, IL-6, and IL-12 in a cohort of patients with early onset rheumatoid arthritis (RA) treated with either cyclosporin A (CyA) or with combination therapy of CyA plus hydroxychloroquine as disease modifying antirheumatic drugs. Methods. We studied 8 patients receiving CyA and 12 patients receiving CyA plus hydroxychloroquine. IL-3, IL-4, IL-6, IL-10, and IL-12 were determined by ELISA at entry, after 2 weeks, after one month, after 6 months, and after 12 months. Rheumatoid factor levels and the possible appearance of monoclonal gammopathies over time were studied by immunofixation and immunoblotting techniques. Results. The pooled data show that at entry only the median baseline levels of IL-10 (3.9 vs 1.6 pg/ml; p < 0.01) and IL-6 (16.9 vs 1.4 pg/ml, p <0.001) were higher in patients than in controls. IL-4 was not detectable. Some patients at entry (those with the longest disease duration) had detectable levels of IL-3. Only levels of IL-10 decreased significantly between entry and final values, in monotherapy and combination therapy as well. A single transient monoclonal band was observed after 6 months of treatment, which disappeared afterwards. No difference was seen in any of the cytokines between the CyA and the CyA plus hydroxychloroquine treated patients. Conclusion. During treatment with either CyA or CyA plus hydroxychloroquine, IL-10 levels decreased significantly. No additive effect of the 2 drugs was detected.