Recently enhanced T-helper type 17 (Th17) immune responses and deficient CD4(+) CD25(hi) FoxP3(+) regulatory T cells (Tregs) have been reported in acquired aplastic anemia (AA).
CD4(+)CD25(+) regulatory T cells (Tregs) were believed to control development and progression of autoimmunity by suppressing autoreactive effector T cells, but little was known regarding the function of Tregs in AA.