CD4 and acute myeloid leukemia: Compared with normal Tregs, AML Tregs significantly promoted the apoptosis of both normal and AML CD4+CD25− T cells (34.40 ± 2.10% vs. 55.27 ± 3.47%, P = 0.0068; 32.47 ± 2.83% vs. 68.93 ± 2.10%, P = 0.0005, respectively).