Association of single nucleotide polymorphisms within cytokine genes with juvenile idiopathic arthritis in the Czech population

Objective. To examine the possible association of juvenile idiopathic arthritis (JIA) with polymorphisms within cytokine genes in the Czech population. Methods. In a case-control study, genotypes of 130 patients with JIA (63 male, 67 female; age at onset 7.6 +/- 4.4 yrs; 43 oligoarticular, 72 polyarticular, 15 systemic form) were compared to 102 healthy unrelated blood donors. Using the polymerase chain reaction technique with sequence-specific primers from the 13th IHWG workshop, we analyzed 19 single nucleotide polymorphisms within 12 different cytokine genes [interleukin (IL)-Ialpha, IL-lbeta, IL-2, IL-4, IL-6, IL-10, IL-12, transforming growth factor (TGF)-beta, interferon (IFN)-gamma], and related molecules (IL-IR, IL-IRA, IL4Ralpha). Genotype frequencies were compared using chi-square analysis, and the significance level was corrected for the number of independent tests. Results. Significant positive association was found for the G allele of the IL-4 -1098 T/G polymorphism, which was carried by 10% of cases and 25% of controls [odds ratio (OR) 0.32, 95% confidence interval (CI) 0.16-0.67, corrected p = 0.038). Also, a nonsignificant increase in the frequency of the IL-1beta +3962 C allele was detected in cases (96%) versus controls (84%) (OR 4.65, 95% CI 1.64-13.2, corrected p = 0.091). We did not replicate previously found associations with the IL-1alpha, IL-6, IL-10, and IL-1RA polymorphisms. Conclusion. Our study showed association with JIA for the IL-4 -1098 T/G polymorphism. It also underlines the genetic contribution of IL-1 polymorphisms to the pathogenesis of JIA, as another polymorphism within the IL-1beta may influence the risk of the disease.