Association Analysis of Interleukin-1 Gene Cluster Polymorphisms with Ischemic Stroke in a Chinese Population.

Chronic inflammatory process acted an important role in atherothrombosis. Interleukin-1 (IL-1) is one of the key modulators of the inflammatory response, and its activity is critically regulated by its receptor antagonist (IL-1ra). Recently, several interleukin-1 cluster gene polymorphisms may associated with acute coronary syndrome have been reported, although with contrasting results. The associations of a variable number tandem repeat (86bp) polymorphism in intron 2 of IL-1ra and of the -511C/T polymorphism of IL-1β with the risk of the ischemic stroke were studied. 112 ischemic stroke patients of Chinese ancestry studied within ten days after presentation were compared with 95 ethnically matched healthy volunteers. 56 among these 112 stroke patients were followed for six months to have prognosis evaluated through measuring Modified Rankin Scale (RS) and Barthel Index (BI). 60 stroke patients had measured the plasma IL-1ra and C-reative protein (CRP) values. The frequency of the IL-1RN 1/1 genotype in the 112 stroke patients was significantly higher than those in healthy volunteers (93.7% vs 82.1%, p<0.05). The frequency of the IL-1RN allele 1 in the 112 stroke patients was significantly higher than those in healthy volunteers (96.4% vs 90.5%, p<0.01, OR=3.23, 95% CI 1.32–7.91). No significant association was seen for the IL-1β-511 C/T polymorphism. In the six months followed group, IL-1RN1/2 genotype carriers had higher BI scores compared with IL-1RN1/1 genotype carriers (98.00 vs 84.80, p<0.01), and patients with lower plasma IL-1ra value (below the median value 186.55pg/ml) had higher BI scores (95.00 vs 77.19, p<0.05), but no significant influence of CRP values and IL-1ra on prognosis or showed no significantly association on plasma IL-1ra and CRP values with IL-1β-511 C/T or IL-1RN genotpye studied in stroke patients. Our results implicate the IL-1ra gene in the susceptibility to ischemic stroke, which may be a useful clue for pharmacological intervention in IL-1 production.