Serum interleukin-41 concentrations are decreased in women with rheumatoid arthritis and are not affected by menopausal status, disease activity, or medication

Introduction Rheumatoid arthritis (RA) is an autoimmune inflammatory disorder characterized by immunobiological homeostasis. The recently discovered cytokine interleukin-41 (IL-41) is among the immunobiological components suggested to have modulatory effects in RA and has shown up-regulated levels in patients. However, IL-41 has not been explored during the pre- (PRM) and post-menopausal (POM) periods in women with RA, and its relationship to disease activity and medications has not been well studied. Materials and methods In this case–control study, serum IL-41 concentrations were quantified in 120 women with RA (70 PRM and 50 POM) and 110 control women using an enzyme-linked immunosorbent assay kit. Thirty patients were newly diagnosed (ND) and 90 patients were on treatment with etanercept (a tumor necrosis factor inhibitor; TNF) plus methotrexate (MD). Results Median IL-41 concentrations (interquartile range) were significantly lower in RA patients than in control women (49.8 [32.5–79.5] vs. 104.7 [76.9–134.6]pg/mL; probability <.001). As indicated by the area under the curve, .827, IL-41 showed reliable discrimination between RA patients and HC. IL-41 concentrations stratified by menopausal status (PRM vs. POM), disease activity score 28 (<3.2 vs. ≥3.2), and medication (ND vs. MD) showed no significant difference in each stratum. Conclusions In contrast to previous studies, serum IL-41 concentrations were significantly decreased in the present cohort of women with RA. These concentrations were not affected by menopausal status, disease activity, or medication. Data from the current study suggest that IL-41 is involved in the pathophysiology of RA.