Influence of cyclosporin A on cytokine levels in synovial fluid and serum of rats with antigen-induced arthritis.

The effects of the T-cell-directed immunosuppressant cyclosporin A (CsA) on the development of antigen-induced arthritis (AIA) in rats as well as on cytokine levels in synovial fluid and serum were determined. The treatment with CsA effectively inhibited the chronic phase of arthritis as demonstrated by decreased joint swelling and reduced histological arthritic score. In animals with AIA the level of IL-6 in the synovial fluid and serum is increased, showing good correlation with the severity of the disease. The CsA treatment reduced IL-6 levels to normal. IL-1, IL-2 and TNF-alpha do not seem to be directly involved in the pathogenic mechanisms of chronic arthritis.