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.