Level of Interleukin 37 (IL-37) in Children with Systemic Lupus Erythematosus and Its Correlation with Disease Activity

Background: Systemic lupus erythematosus (SLE) is an autoimmune disorder caused by auto-antibodies against self-antigens. Interleukin 37 (IL-37) is a member of IL-1family, and it is a key cytokine in regulating inflammation. We aimed to detect the level of IL-37 in SLE patients and to correlate it with disease activity. Methods: A cross-sectional study included fifty children with SLE following up at the pediatric rheumatology clinic in specialized children's hospital, Cairo University and chosen randomly; aged up to 16 years and thirty, apparently healthy children with matched age and gender, were assigned as the control group. In all cases and controls, full history was taken, full physical examination performed and laboratory investigations including level of IL-37 were done. Results: Levels of IL-37 in the 50 cases with SLE were higher than in the 30 controls with statistically significant difference (P = 0.028). Level of IL-37 was higher in active cases than in inactive cases but without statistically significant difference (P = 0.58). Level of IL-37 level in cases with mild activity was lower than in cases with moderate or severe activity but without statistically significant difference (P = 0.23). Conclusions: level of IL-37 was higher in our SLE patients than in controls and it is higher in active cases than inactive cases. IL-37 is correlated positively with duration between onset and diagnosis of disease and SLEDAI-2K activity score.