FOXP3 and myocardial infarction: In contrast, significant T-cell proliferation and decreased levels of TGF-β, IL-2, and IL-10 were observed in the xenogeneic co-culture conditions (Fig. 1E. Forkhead box protein 3 (FOXP3) expressing CD4+ T cells (Treg cells) are accumulated in the injured myocardium after MI injury and plays an important role to recover heart function [28–30].