IL-37 Plays a Beneficial Role in Patients with Acute Coronary Syndrome

BACKGROUND: Interleukin-37 (IL-37) acts as an inhibitor of innate and adaptive immunity. However, the exact role of IL-37 in the patients with acute coronary syndrome (ACS) remains to be elucidated. METHODS: Patients were classified into 4 groups: normal coronary artery (NCA), stable angina (SA), unstable angina (UA), and acute myocardial infarction (AMI). The circulating Treg, Th1, and Th17 frequencies were measured. The effect of IL-37 on stimulated peripheral blood mononuclear cells (PBMCs) and the influence of IL-37 on DCs were explored. In addition, the role of IL-37-treated tDCs on Treg cell expansion and the stability of these tDCs were also tested. RESULTS: Our results showed that the circulating Treg frequencies were decreased, while Th1 and Th17 frequencies were increased in ACS patients, and that IL-37 expanded Tregs but suppressed Th1 and Th17 cells in activated PBMCs derived from ACS patients. Of note, IL-37-treated human DCs obtained a tolerogenic phenotype, and such tDCs promoted expansion of Tregs and decreased the Th1 and Th17 populations when cocultured with CD4(+) T cells. Interestingly, IL-37-treated DCs from patients with ACS are phenotypically and functionally comparable to IL-37-treated DCs from NCA patients, and tolerogenic properties of IL-37-treated DCs were highly stable. CONCLUSION: In conclusion, our results reveal a beneficial role of IL-37 in the patients with ACS and suggest that autologous IL-37-treated tDCs may be a novel therapeutic strategy for the patients with ACS.