Levels of interleukin-2 and interleukin-6 in serum and synovial fluid of patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disorder, which is characterised by symmetric, erosive synovitis and sometimes with multisystem involvement. Inflammatory diseases such as RA are associated with increased production of cytokines. We aimed to investigate interleukin-2 (IL-2) and interleukin-6 (IL-6) levels in both serum and synovial fluid (SF) of patients with rheumatoid arthritis (RA), osteoarthritis (OA), and reactive arthritis (REA). In this study, we measured erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) levels, both serum and SF IL-2 and IL-6, in 39 patients with RA, OA, and REA.Erythrocyte sedimentation rate and C-reactive protein levels were higher in patients with RA compared with OA and REA as characteristic laboratory findings of the disease. Both serum and SF IL-2 and IL-6 levels were higher in patients with RA than in patients with OA and REA.These findings show high production of IL-2 and IL-6 in RA serum and SF, indicating that activated T cells play a role in the pathophysiological events of RA.