The IL-1 Receptor Antagonist Gene Polymorphism in Turkish Patients with Juvenile Idiopathic Arthritis

Abstract

Objective: Interleukin-1 receptor antagonist (IL-1Ra) gene (IL-1RN) polymorphism is associated with disease susceptibility and activity in several inflammatory diseases. The aim of this study was to investigate IL1RN genotype and its associations with different subtypes of juvenile idiopathic arthritis ( JIA) in a group of Turkish patients. Methods: A total of 273 subjects were included in this cross sectional study. Genomic DNA was obtained from the peripheral blood of 76 patients with juvenile idiopathic arthritis and 197 reference subjects. A variable number tandem repeat (VNTR) polymorphism in the second intron of the IL-1RN gene was detected by PCR-based methods. Probing pocket depth, clinical attachment loss, plaque accumulation and bleeding on probing (BOP) were recorded. The data were analyzed by the χ2 test, logistic regression and Mann-Whitney U test. Results: The frequency and carriage rate of IL1RN*2 were significantly increased in JIA patients compared with the controls. The high representation of IL1RN*2 in 34.3% of the 16 patients with systemic onset JIA, 27.5% of the 20 patients with polyarticular JIA, and 31.4% of the 11 patients with enthesitis-related arthritis was found. Conclusion: This study showed genetic associations between the IL-1Ra gene and the systemic subtype of JIA. These finding give a better understanding of the underlying etiological cause of subgroup of JIA and could lead to different therapeutic approaches each subgroups of JIA.