As shown in Figure 2B, PD-1+CD4+CD25high T cells exhibited a greater inhibition of the proliferation of CFSE-labeled CD4+CD25− T cells than the negative counterpart PD-1−CD4+CD25high T cells from the same patients with AML, similarly to the results summarized by a previous report (27). This evidence concerns the gene CD4 and acute myeloid leukemia.