Association study between rs2275913 genetic polymorphism and serum levels of IL-17A with risk of coronary artery disease

Coronary artery disease (CAD) is now considered as a main cause of disability and mortality in Iranian population. Inflammatory processes are the initial events in the development of CAD. Interleukin-17A (IL-17A) is a pro-inflammatory cytokine and its genetic variation may contribute to the development of CAD. This study investigated serum levels and the G-197A polymorphism of IL17A in a group of patients with CAD and healthy controls. The study population included 220 angiographically verified CAD patients and 220 healthy controls. Genotyping of G-197A polymorphism of IL17A was done by PCR-RFLP method and serum level of IL-17 was measured by enzyme immunoassay. Results indicated that serum concentration of IL-17A was significantly higher in CAD group than control group (P<0.001). Also, serum levels of IL-17A was significantly higher in carriers of GA and AA genotype relative to carriers of GG genotype in both study population (P<0.05). The G-197A polymorphism of IL17A increased the risk of CAD in mutant homozygous (P=0.007) but not heterozygous (P=0.104) genotype. Moreover, this polymorphism was associated with higher risk of CAD development in allelic (P=0.041) model. However, no significant association was observed between genotypic distribution of G-197A polymorphism and the number of stenotic vessels (P>0.05). In conclusion, the present study indicated G-197A polymorphism of IL17A as a significant contributor to the development but not to the severity of CAD. Moreover, elevated serum levels of IL-17A were identified as a susceptibility marker of CAD.