Interleukin-1 receptor antagonist gene polymorphism and susceptibility to ischemic stroke.

Cytokines gene polymorphisms have been implicated in susceptibility to ischemic stroke. This study aims to determine the influence of the polymorphism within the intron 2 of the interleukin- 1 receptor antagonist (IL-1Ra) gene on the susceptibility to stroke. A variable number of tandem repeats (VNTR) in intron 2 of the IL-1Ra gene was analyzed in 148 patients with stroke and 161 healthy volunteers from the same area. The carriage rate of allele 2 of IL-1Ra gene, low producer, was significantly higher in patients with stroke compared to the controls (29% vs 21% p = 0.02). Frequency of IL1RN1/IL1RN1 genotype in the patients was significantly lower than the controls (49% vs 66% p = 0.003). The distribution of homozygous genotypes of IL1RN2 was not different between the controls and stroke patients while the heterozygous genotype was more frequent among the patients. (39% vs 25%, respectively). Multiple logistic regression analysis demonstrated that individuals who carry allele 2 for IL-1Ra gene had a significantly higher risk for ischemic stroke with an odds ratio of 2.48 (95% CI, 1.67, 3.51, p = 0.006). These data suggest that allele 2 of the IL-1Ra intron 2 gene represents a susceptibility factor in the development of ischemic stroke.