Our data highlighted a significantly higher frequency of CD4+ CD25high FoxP3+ cells in AML samples (0.83 ± 0.75%) than in controls (0.19 ± 0.15%) (P = 0.012) (Figure 1e), whereas no difference were observed in the frequency of CD4+ CD25+ FoxP3+ cells (P = 0.38, data not shown). Here, CD4 is linked to acute myeloid leukemia.