Impaired thymic export and apoptosis contribute to regulatory T-cell defects in patients with chronic heart failure

Animal studies suggest that regulatory T (T(reg)) cells play a beneficial role in ventricular remodeling and our previous data have demonstrated defects of T(reg) cells in patients with chronic heart failure (CHF). However, the mechanisms behind T(reg-)cell defects remained unknown. We here sought to elucidate the mechanism of T(reg-)cell defects in CHF patients.We performed flow cytometry analysis and demonstrated reduced numbers of peripheral blood CD4(+)CD25(+)FOXP3(+)CD45RO(-)CD45RA(+) naïve T(reg) (nT(reg)) cells and CD4(+)CD25(+)FOXP3(+)CD45RO(+)CD45RA(-) memory T(reg) (mT(reg)) cells in CHF patients as compared with non-CHF controls. Moreover, the nT(reg)/mT(reg) ratio (p