Increased Th17 cells in coronary artery disease are associated with neutrophilic inflammation

OBJECTIVE: Atherosclerosis is a progressive disease characterized by a series of inflammatory responses in the large and medium arteries. Th17 cells, a distinct T cell lineage which has recently been identified, have a proinflammatory role and are implicated in many inflammatory conditions in humans and mice. The present study was designed to assess whether Th17 cells are associated with human coronary atherosclerosis. DESIGN: Flow cytometry was used to examine Th17 cell frequencies in patients with coronary atherosclerosis and in healthy individuals. ELISA and real-time RT-PCR were performed to investigate circulating interleukin (IL)-17 (the signature cytokine of Th17 cells) and IL-8 (the cytokine induced by IL-17) protein and mRNA levels. RESULTS: Significantly increased Th17 cell frequencies are observed in patients with coronary artery disease compared to healthy controls. The protein and mRNA levels of IL-17 and IL-8 are also significantly elevated in patients with atherosclerosis compared to healthy volunteers. Furthermore, mRNA levels of IL-17 and IL-8 are correlated with each other and with peripheral neutrophil counts. CONCLUSIONS: Our findings indicate that Th17 cells and their signature cytokine are involved in the process of atherogenesis. These data suggest that Th17 cells link T cell activity with neutrophilic inflammation in atherosclerosis.