IL-6 promoter polymorphism increased risks of recurrent stroke in the young patients with moderate internal carotid artery stenosis.

Interleukin-6 (IL-6) is a pleiotropic cytokine with both pro-inflammatory and anti-inflammatory properties. Increased serum IL-6 is associated with higher risk of cerebral vascular diseases, however, the circulating levels of IL-6 vary greatly between individuals for bioenvironmental or genetic interferes by IL-6 transcription, therefore, this study was to investigate if IL-6 promoter polymorphisms predict the recurrence of young stroke. A total of 94 patients with moderate internal carotid artery stenosis and 94 healthy subjects were selected. Color Doppler was used to screen internal carotid artery stenosis, PCR restriction enzyme fragment length polymorphism for genotypes. Stroke recurrence rates in patients with different genotypes of IL-6 promoter were evaluated by 1-year follow-up. The frequencies of 634C/G genotype of IL-6 promoter were CC 38.29%, CG 46.81%, and GG 14.90%, while CC 59.51%, CG 35.11%, GG 6.38% in the control group (P < 0.01). The frequency of G allele was significantly higher than that in the control group (38.30% vs 21.28%, P < 0.01). The relative risk was 2.2838, and 95% confidence interval was 1.0026 to 5.2026, adjusted age, sex, blood pressure, BMI, blood lipid levels and IL-6 (P < 0.05). The recurrent rate was 25.53% at 1-year follow-up; the recurrent rate among carriers with wild-type G allele (CG + GG genotype) was 32.76%, but CC 13.89% (P < 0.01). IL-6 G allele promoter increased stroke recurrent risk, therefore, it would be a predictor for recurrence of stroke in the young with moderate internal carotid artery stenosis.