Associations of Common Genetic Variants on IL-17 Genes and Carotid Intima-Media Thickness.

ABSTRACT

AIM: Atherosclerosis is a chronic inflammatory process of the arterial wall and carotid intima-media thickness (cIMT) is regarded as its early marker. Several members of the IL-17 family are involved in pro-inflammatory functions. The specific aim of the study was to explore the relationships of common genetic variants on IL-17 genes with cIMT thickening. METHODS: In the discovery stage, 146 SNPs on 11 IL-17 genes were screened for their relationships with cIMT by a case-control study that enrolled 284 and 464 subjects who had thicker and normal cIMT, respectively. Findings were replicated by an independent case-control study that enrolled 282 subjects who had thicker cIMT and 282 age-sex-matched subjects who had normal cIMT. RESULTS: Among 134 eligible SNPs in the discovery study, only IL-17RC rs279545 was significantly correlated with cIMT (p=6.9×10-5). The rs279545 and 2 nearby linked SNPs rs55847610 and rs3846167 were included in the validation study. We found that the rs279545＊G, rs55847610＊G, and rs3846167＊C were correlated with significantly higher likelihoods of having thicker cIMT. The corresponding multivariate-adjusted ORs were 1.462 (95% CI 1.055-2.027), 1.481 (95% CI1.090-2.013), and 1.589 (95% CI 1.147-2.200), respectively. Analyses of rs279545-rs55847610 haplotypes showed that the multivariate-adjusted OR for A-A haplotype was significantly decreased (OR=0.665, 95% CI 0.487-0.908) and for G-G haplotype was significantly increased (OR=1.539, 95% CI 1.097-2.161). CONCLUSIONS: We first correlated cIMT, a preclinical clinical cardiovascular marker, with IL-17RC, the key molecule in the IL-17 signaling pathway. Our results indicated that IL-17RC may play critical role in the development of atherosclerotic diseases.