Expression level of serum Interleukin-37 in Rheumatoid Arthritis patients and its correlation with Disease Activity Score

Abstract

Background: Interleukin-37 (IL-37) is a member of IL-1 cytokine family. IL-37 immunosuppresses the pathogenesis of rheumatoid arthritis via down-regulating pro-inflammatory cytokines. The aim of the current study was to evaluate the expression level of IL-37 in rheumatoid arthritis (RA) patients and its correlation with the disease activity score in 28 joints (DAS-28). Methods: In the current study, forty-six RA patients, having a ratio of 19 males and 27 females, and twenty healthy controls (11 males and 9 females) were included. DAS-28 was measured on the basis of patients’ clinical observations of the tender and swollen joints, physical examination and erythrocyte sedimentation rate (ESR). ESR was measured according to the Westergren method. Serum IL-37 level was measured by ELISA. Depending upon the DAS28 calculations the patients were divided in four groups as; 19 in remission, 6 had mild disease activity, 6 were in moderate state and 15 patients were found with severe disease activity. Results: Serum IL-37 levels were found markedly raised in RA patients (mean = 862.6) than in healthy individuals (mean ± SD = 4.4 ± 1.74 pg/ml). Further, our results suggest that level of IL-37 increased significantly from mild (mean ± SD = 829.17 ± 61.40 pg/ml) to moderate (mean ± SD = 1307.5 ± 165.1 pg/ml) and severe (mean ± SD = 1607 ± 86.8 pg/ml) disease prognosis. Conclusion: Thus we conclude, IL-37 has a positive correlation with DAS28 and thus has a potential role in RA pathogenesis.

Keywords

• Interleukin 37
• rheumatoid arthritis
• autoimmune disorder
• inflammation
• disease activity score