Elevated plasma levels of interleukin-2 and soluble IL-2 receptor in ischemic heart disease

Background: T-lymphocytes are present in significant numbers in the atherosclerotic plaque, but their role in the progression and pathogenesis of coronary syndromes remains poorly understood. Hypothesis: We sought to determine the relationship between T-lymphocyte activation and ischemic heart disease by measuring plasma levels of cytokines related to T-lymphocyte function in patients with stable and unstable angina. Methods: Plasma levels of interleukin-2 (IL-2) and soluble IL-2 receptor (sIL-2R) were measured in 105 patients: 66 with stable angina, 24 with unstable angina, and 15 healthy controls. Patients who presented to the cardiac catheterization laboratory with unstable or stable anginal syndromes for coronary angiography or percutaneous coronary intervention enrolled in the study. Results: Mean levels of IL-2 were significantly higher in patients with stable angina than in those with unstable angina. The differences between stable angina and control groups, or between unstable angina and control groups, were not statistically significant. Mean levels of sIL-2R were significantly higher in patients with stable angina than in either patients with unstable angina or control patients. Conclusions: Levels of IL-2 and sIL-2 receptor are significantly elevated in patients with stable angina, but not in patients with unstable angina. The contribution of T-lymphocytes to the development of both stable and unstable angina requires further investigation.