Cytokines, including interleukin-1 (IL-1), seem to contribute towards the pathogenesis of juvenile idiopathic arthritis (JIA), so this study was designed to evaluate the associations of IL-1 gene cluster and IL-1 receptor (IL-1R) gene single nucleotide polymorphisms (SNPs) with JIA proneness in Iranian population.
Genomic DNA of 55 Iranian patients with JIA and 140 controls were extracted and typed for IL-1α gene at position -889, IL-1β gene at positions -511 and +3962, IL-1R gene at position Pst-I 1970, and interleikin-1 receptor antagonist (IL-1Ra) gene at position Mspa-I 11100, using polymerase chain reaction with sequence-specific primers method, and compared between patients and controls.
The CC genotype of IL-1Ra at Mspa-I 11100 position was found to be more frequent in patients with JIA compared to healthy individuals (P=0.03), although the CT genotype at the same position was significantly higher in the control group in comparison with patients with JIA (P=0.02). No significant differences were observed between the two groups of case and control for IL-1α (-889 C/T), IL-1β (-511 C/T and +3962 C/T) and IL-1R (Pst-1 1970 C/T).
The results of the present investigation suggest that certain IL-1Ra gene variants are associated with individuals' susceptibility to JIA. Nevertheless, further studies are required to establish the results of the current study.