CD8+CD28+ T cells might mediate injury of cardiomyocytes in acute myocardial infarction.

CD8+ T cells accumulate in the necrotic myocardium of acute myocardial infarction (AMI). It is unclear whether CD8+CD28+ T cells, a specific subset of CD8+ T cells, contribute to myocardial injury. In this study, 92 consecutive patients with AMI and 28 healthy control subjects were enrolled. The frequency of CD8+CD28+ T cells in peripheral blood samples was assayed by flow cytometry. Plasma cardiac troponin I (TNI) and left ventricular ejection fraction (LVEF) were determined. Long-term prognosis of the patients was evaluated by major adverse cardiac and cerebrovascular events (MACCE) over a 12-month follow-up period. Our findings indicated that patients with AMI who presented with high numbers of CD8+CD28+ T cells had an increased infarction size and aggravated ventricular function. We proposed that cytotoxic CD8+CD28+ T cell-mediated myocardial necrosis may act as a novel and alternative pathway of AMI.