Abstrakt
Objectives To study the association of systemic and local interleukin-35 (IL-35) levels in rheumatoid arthritis. Methods 37 patients with treatment naive early RA, 49 with established RA and 29 control patients with osteoarthritis (OA) were studied.
Serum and paired synovial fluid samples were analysed for IL-35. Disease activity of RA patients was assessed according to the 28-Joint Count Disease Activity Score (DAS28).
Results The levels of serum IL-35 were significantly higher in patients with treatment naive early RA compared to those with established disease and control OA subjects. In addition, serum levels of IL-35 significantly decreased 12 weeks after initiation of glucocorticoids and conventional synthetic disease modifying antirheumatic drugs in patients with treatment naive early RA.
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). Conclusion This is the first study showing elevated circulating levels of IL-35 in treatment naive early RA, its significant decrease after treatment initiation and positive association between increased synovial fluid IL-35 and disease activity in patients with long-lasting RA.