Abstract: Rheumatoid arthritis (RA) is a chronic progressive autoimmune disorder, the mechanism of which is not clear yet. Cytokines play a key role in the pathogenesis of RA. Recent studies on cytokine involvement in autoimmune diseases have found that, as a new member of interleukin-1 (IL-1) family, IL-37 can participate in the regulation of signaling pathway and play its anti-inflammatory roleextracellular binding to membrane receptor and intracellular complex formation. Studies have shown that the level of IL-37 in healthy people is extremely low and overexpressed in RA patients, and the serum level of IL-37 in RA patients is positively correlated with the level of pro-inflammation cytokines such as tumor necrosis factor-α (TNF-α), IL-6 and IL-1α, the level of C reactive protein and 28-joint disease activity score (DAS28). However, IL-37 treatment can alleviate the inflammation and pathological symptoms of collagen-induced arthritis (CIA) mice, which indicates that IL-37 has anti-inflammatory effect via negative feedback. The specific anti-inflammatory mechanism may be related to mothers against decapentaplegic homolog 3 (SMAD3) pathway and nuclear factor kappa-B (NF-κB) pathway. This article reviews the structure and of IL-37, the receptor and its signal pathway and the function and its mechanism in RA, which provides references for the further study of IL-37 and RA.

Key words: interleukin-37 (IL-37), rheumatoid arthritis (RA), autoimmune disorder