Abstract: Objective To detect the serum level of IL-37 in patients with rheumatoid arthritis （RA） to uncover the correlation of IL-37 with rheumatoid arthritis. Methods Fifty-nine patients diagnosed as rheumatoid arthritis were enrolled in the study. Disease activity was evaluated by calculating the 28-joint Disease Activity （DAS28） Score based on the clinical information． RA patients were divided into active and inactive groups according to the DAS28 score．The serum levels of IL-37,TNF-α,IL-17,IL-10 were measured by enzyme linked immunosorbent assay （ELISA） and C-reaction protein （CRP） by nephelometry. Results The serum levels of IL-37 was higher in RA group compared with the other two groups （P<0.01）. In addition,IL-37 levels in the active group were elevated markedly compared with those in the inactive group. More importantly,IL-37 showed a significantly positive correlation with DAS28,CRP,TNF-α and IL-17 concentrations in RA patients,but not with IL-10 by Spearman's test. Conclusion These findings show that IL-37 indicates the disease activity of RA and might be a valuable biomarker for auxiliary diagnosis of RA.

Key words: IL-37, IL-17, TNF-α, IL-10, RA