Interleukin-37 in endometriosis

•IL-37 mRNA was highly expressed in endometriosis.•IL-37 expression correlates with endometriosis severity.•A significant inverse correlation was observed between IL-37 mRNA and NFκB mRNA expression.•The affected NFκB mRNA expression in endometriosis contributed to the exhibited increase of IL-37.•IL-37 may dampen NFκB activation in endometriosis patients.

Interleukin-37 (IL-37) has been identified as a novel anti-inflammatory cytokine. The present study aimed to evaluate the expression of IL-37 in serum and in peritoneal fluid to determine its clinical significance in endometriosis. Enzyme-linked immunosorbent assay (ELISA) was performed to examine serum IL-37 levels in patients with endometriosis and healthy controls. Peritoneal fluid IL-37 mRNA and NFκB expression were quantified by real-time reverse transcription polymerase chain reaction assays. The association of IL-37 levels with clinical factors and prognosis of endometriosis was analysed. We found that IL-37 levels in PF and in serum were significantly higher in patients with endometriosis compared to women without endometriosis (P = 0.0005). IL-37 levels were highly expressed in PF [132.38 ± 34.62 pg/mL; P < 0.0001] than in serum [74.10 ± 13.49 pg/mL] in endometriosis patients. IL-37 mRNA expression contrasted with NFκB mRNA expression in PF from patients with endometriosis. A significant inverse correlation was observed between IL-37 mRNA and NFκB mRNA expression. IL-37 expression correlates with endometriosis severity. The affected NFκB mRNA expression in endometriosis contributed the to exhibited increase of IL-37. The increased levels of IL-37 may dampen NFκB activation in endometriosis patients.