Regulatory T cell frequency and function in acute myocardial infarction patients and its correlation with ventricular dysfunction.

A high percentage of patients with acute coronary syndrome develop heart failure due to the ischemic event. Regulatory T (Treg) cells are lymphocytes with suppressive capacity that control the immune response and include the conventional CD4+ CD25hi Foxp3+ cells and the CD4+ CD25var CD69+ LAP+ Foxp3- IL-10+ cells. No human follow-up studies focus on Treg cells' behavior after infarction and their possible relationship with ventricular function as a sign of post-ischemic cardiac remodeling. This study aimed to analyze, by flow cytometry, the circulating levels of CD69+ regulatory T cells and CD4+ CD25hi Foxp3+ cells, its IL-10+ production as well as their function in patients with acute myocardial infarction (AMI), and its possible relation with ventricular dysfunction. We found a significant difference in the percentage of CD4+ CD25hi Foxp3+ cells and IL-10+ MFI in patients with AMI at 72 hours compared with the healthy control group, and the levels of these cells were reduced six months post-AMI. Regarding the suppressive function of CD4+ CD25+ regulatory cells, they were dysfunctional at three- and six-months post-AMI. The frequency of CD69+ Treg cells was similar between patients with AMI at 72 hours post-infarction and the control groups. Moreover, the frequency of CD69+ Treg cells at three months and six months post-ischemic event did not vary over time. Treg cells play a role in regulating inflammation after an acute myocardial infarction, and its function may be compromised in this pathology. This work is the first report to evaluate CD69+ Foxp3- Treg cells in AMI patients.