Highly Increased Levels of Tumor Necrosis Factor-alpha and Other Proinflammatory Cytokines in Psoriatic Arthritis Synovial Fluid

Objective: To investigate the potential role of cytokines in psoriatic arthritis (PsA) by assessing the profiles of the proinflammatory cytokines in synovial fluid (SF) of PsA in comparison with rheumatoid arthritis (RA) and osteoarthritis (OA).

Methods: Levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 1 (IL-1), IL-6, and IL-8 were measured in SF using ELISA.

Results: Levels of TNF-alpha, IL-1beta, and IL-8 were significantly higher in PsA SF than in OA SF, although lower than in RA SF. No difference was detected in the IL-6 levels between PsA and RA SF, both of which were much higher than in OA SF.

Conclusion: The pattern of expression of proinflammatory cytokines seen in PsA is similar to that in RA. Since PsA is also a destructive arthropathy, cytokines, in particular TNF-alpha and IL-1, may be principle factors in joint destruction.