IL-6 and IL-1 receptor antagonist in stable angina pectoris and relation of IL-6 to clinical findings in acute myocardial infarction

Objectives. To determine if increased inflammatory activity, as reflected b y interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) level s, is present in patients with stable angina pectoris and if IL-6 levels on admission to the coronary care unit in patients with acute myocardial infa rction (AMI) are related to heart failure and fever response. Subjects and methods. We studied 28 patients with stable angina pectoris en rolled for coronary angiography, and compared them with sex- and age-matche d controls. Thirty-four patients with AMI were studied and samples for dete rmination of IL-6 levels were taken on admission within 36 h of onset of sy mptoms. IL-6 and IL-1ra were determined in serum by enzyme immunoassay. Results. Levels of IL-6 and IL-1ra were higher in patients with stable angi na pectoris than in controls (mean 4.6 +/- 3.6 vs. 3.0 +/- 2.9 ng L-1, P < 0.03, and 774 +/- 509 vs. 490 +/- 511 ng L-1, P < 0.01, respectively). IL-6 and IL-1ra levels were not related to angiographic findings. IL-6 levels w ere high in patients with AMI (38.9 +/- 75.6 ng L-1). Patients with prolong ed fever (duration > 4 days) had higher IL-6 levels (94.7 +/- 138.2 vs. 21. 7 +/- 29.7 ng L-1, P < 0.05). IL-6 levels were not related to heart failure . Conclusions. Our results indicate that increased inflammatory activity is p resent not only in acute coronary syndromes, but also in a chronic form of ischaemic heart disease, giving further evidence for a central role of infl ammatory processes in coronary artery disease. With regard to AMI, we found increased inflammatory activity in patients with prolonged fever.