Association of common polymorphisms in IL-6 and IL6ST genes with levels of inflammatory markers and coronary stenosis

Inflammation is an important factor in the onset and development of pathological lesions of coronary arteries. Various cytokines, including interleukin-6 (IL-6), and pattern recognition receptors, such as C-reactive protein (CRP), are the key inflammatory mediators. We aimed to identify associations of single nucleotide polymorphisms (SNPs) rs1800795 of the IL-6 gene and rs3729960 of the IL6ST gene with levels of inflammatory markers and coronary lesions. The study included 316 men and 131 women (mean age 61.2 +/- 9.4 years) subjected to coronary angiography. IL-6 levels were assayed by ELISA and high sensitivity CRP (hsCRP) levels were measured by turbidimetry. The rs1800795 and rs3729960 genotypes of the IL-6 and IL6ST genes, respectively, were determined by real time PCR. Data were analyzed by the SPSS software. In women, the CC genotype (N = 31) of rs1800795 of the IL-6 gene is associated with lower concentrations of hsCRP in the dominant model (GG + CG; N = 38 and N = 62, respectively) and the corresponding hsCRP levels were significantly different (P = .015) at 1.70 mg/l (25% 0.75; 75% 3.55) and 3.30 mg/l (25% 1.20; 75% 6.18). In men, these genotypes were not associated with hsCRP levels. Distribution of allele frequency of rs1800795 of the IL-6 gene in groups with and without coronary lesions indicate that the G allele has significantly higher frequency in men but not in women with coronary atherosclerosis (OR 2.45; 95% CI 1.31-4.72; P = .003). Thus, in women, rs1800795 of the IL-6 gene is associated with hsCRP levels and in men, rs1800795 is associated with presence of coronary lesions.