Synovial fluid IL-35 levels were significantly higher in RA compared to OA patients, were significantly elevated compared to serum counterparts and correlated with synovial fluid leukocyte count (r=0.412; p<0.01), serum CRP levels (r=0.362; p<0.05) and DAS28 (r=0.430, p<0.01). The gene discussed is CRP; the disease is rheumatoid arthritis.