The association of functional polymorphisms of IL-6 gene promoter with ischemic stroke: Analysis in two Chinese populations

Polymorphisms of G-572C and G-174C in the interleukin-6 (IL-6) promoter can affect both the transcription and secretion of IL-6 and may be involved in inflammation related to and the pathogenesis of ischemic stroke (IS) However, whether IL-6 polymorphisms are indeed risk factors for IS remains controversial. We recruited 748 Chinese IS patients diagnosed by magnetic resonance imaging (MRI) within 24 h of symptom onset and 748 normal healthy controls from two ethnic populations and performed two case-control studies in order to assess the nature of the polymorphisms of IL-6 and any links with IS. Common polymorphic loci in the IL-6 gene promoter were determined by TaqMan SNP genotyping assays Multivariate logistic regression analysis Was used to examine the association between IL-6 genotypes and a diagnosis of IS We found that the C allele frequency at the -174 promoter region of IL-6 was extremely low in both IS patients and controls in both ethnic groups. The G allele of the promoter single nucleotide polymorphism (SNP) G-572C was more common in IS subjects than controls (P = 0 004, corrected for Multiple testing) in the Han Population but not in the Uyghur population. GC carriage therefore increased the risk of IS in the Han ethnic group (OR 1 45, 95% CI 1 13-1 86) In addition. the differences in GG and GC frequency between the two ethnic populations were significant The C allele frequency at the -174 promoter region of IL-6 was rare in Chinese IS patients and controls from either ethnic group We conclude that IL-6-572GC may be ail independent risk factor for IS in the Chinese Han population (C) 2009 Elsevier Inc All rights reserved