Comparison of serum levels of inflammatory markers and allelic variant of interleukin-6 in patients with acute coronary syndrome and stable angina pectoris

Objectives Although the relationship between atherosclerosis and inflammatory cells has been recognized in recent years, the effect of interleukin-6 (IL-6) genetic variants associated with atherosclerosis is still controversial. Therefore, we investigated the association between IL-6 polymorphism and levels of IL-6 in patients with coronary artery disease (CAD). Methods We conducted a case-control study on 294 unrelated participants who were referred to the cardiology department of the university hospital for coronary angiography because of suspected ischernic heart disease. Group I comprised patients with clinically acute coronary syndrome, and group 11 comprised patients (individuals matched for age and sex) with clinically stable angina pectoris; both groups were categorized, based on their angiographic findings, as either having angiographically documented less extensive CAD (11 vessel narrowed) or extensive CAD (>= 2 vessels narrowed). They were studied to examine effect of the IL-6 gene variants in CAD. Genotyping was determined by polymerase chain reaction. Results The IL-6 G/C-1174 polymorphism was found in 19 of 106 (18%) in group I and in four of 188 (2%) in group 11 (P<0.001). Median IL-6 levels were significantly higher in group 1 (6.7 +/- 13.6 pg/ml) than in group 111 (4.1 +/- 3.8 pg/ml) (P<0.05). In addition, high sensitivity C-reactive protein levels were significantly higher in group 1 (8.2 +/- 6.2 mg/dI) than in group B (4.6 +/- 3.4 mg/dI) (P<0.001). Conclusion These results demonstrated that the presence of the IL-6 G/C-174 polymorphism and increased IL-6 and high sensitivity C-reactive protein levels are strongly associated with the inflammatory system and the course of clinical and hemodynamically significant CAD. Coron Artery Dis 19:15-19 (c) 2008 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.