Coculture supernatants obtained from the apoptosis assays were analyzed for IFN-γ, and the data revealed that Tregs from AML patients suppressed the secretion of IFN-γ by both normal and AML CD4+CD25− T cells (P = 0.0065 and P = 0.0004, respectively), especially for autologous CD4+CD25− T cells (the level of IFN-γ decreased from baseline value of 635.0 ± 24.7 pg/ml to 170.5 ± 35.3 pg/ml) (Fig. 4e). Here, CD4 is linked to acute myeloid leukemia.