Serum interleukin-37 (IL-37) and its gene polymorphism in Iranian Behcet's disease patients: Association with disease manifestations and activity

Abstract

IntroductionThe etiopathogenesis of autoimmune inflammatory Behçet's disease (BD) has not been well understood but cytokines and genetic factors might play a role. Interleukin (IL)-37 is an anti-inflammatory cytokine that suppresses both innate and adaptive immunity. This study aimed to assess the possible association between serum levels of IL-37 and its genetic polymorphisms with susceptibility to BD. MethodsSerum levels of IL-37 and its genetic variants were determined using enzyme-linked immunosorbent assay (ELISA) and allele-specific polymerase chain reaction, respectively. ResultsThe results revealed significantly lower level of IL-37 in BD patients (82.8 ± 2.8 pg/ml) compared to the healthy subjects (110.3 ± 11.8 pg/ml, p < 05). Furthermore, significantly lower level of IL-37 (77.2 ± 2.3 pg/ml, p = 0.048) was shown in patients with ocular involvement. In addition, genotypic analysis demonstrated more rs4241122 AA genotype frequency among male BD patients with an active form of disease and those with gastrointestinal manifestations (p = 0.01). However, this genotype was more frequently seen among female patients with an inactive form of disease (p < 0.001). Besides, allelic analysis showed a higher frequency of rs4241122 A allele among male patients with an active form of disease (p = 0.006), as well as among female patients with vascular involvement (p = 0.03). ConclusionOur data indicated that decreased levels of IL-37 might act as a susceptibility factor for BD and ocular involvement among patients. We also found gender-biased associations between genotypes and alleles of rs4241122 and disease manifestations. However, further studies with larger sample sizes are needed to verify these results.