Role of interleukin-17 and interleukin-17-induced cytokines interleukin-6 and interleukin-8 in unstable coronary artery disease

BACKGROUND: Atherosclerosis is a chronic inflammatory disease and interleukins are considered to play a key role in the chronic vascular inflammatory response that is typical of atherosclerosis. The serum levels of several of these cytokines have been found to positively correlate with coronary arterial disease and its sequelae. AIM: The aim of our study was to evaluate the levels of a comparatively new cytokine IL-17, in patients with stable and unstable coronary artery disease in order to assess whether unstable coronary artery disease patients had higher IL-17 levels. MATERIALS AND METHODS: We analyzed the concentrations of IL-17, IL-6, IL-8 and IL-10 using enzyme-linked immunosorbent assay and heat-sensitive C-reactive protein using latex particle-enhanced immunoturbidimetry in 58 consecutive unselected patients divided into three groups: stable angina (n=14), unstable angina (n=24) and acute myocardial infarction (n=20). We further compared them with 20 healthy controls. These 58 patients were also angiographically studied and divided into two groups: simple lesion (n=22) and complex lesion (n=36), on the basis of the coronary plaque morphology. RESULTS: Our results show increased concentrations of the proinflammatory cytokines IL-17, IL-6, IL-8 and heat-sensitive C-reactive protein, and decreased concentration of IL-10 in plasma of unstable angina and acute myocardial infarction patients. Plasma concentration of IL-17 was also positively correlated with plasma concentrations of IL-6 and heat-sensitive C-reactive protein. Our findings further showed that IL-17 values were higher in patients having angiographically visible complex types of lesions but no difference was observed between complex and simple lesion morphology patients. CONCLUSION: In conclusion, these findings point towards a role of inflammation in the form of increased activity of IL-17, IL-6 and IL-8 in patients of unstable angina and acute myocardial infarction and thus suggest that IL-17-driven inflammation may play a role in the promotion of clinical instability in patients with coronary artery disease.