Studies by Wan et al. have demonstrated that the proportion of Tregs in the BM of AML patients is greater than that observed in normal individuals, mainly because regulatory B cells (Bregs) induce CD4+CD25-T cells to transform into Tregs, and the chemokine receptor CXCR4 highly expressed on Tregs facilitates the strong migration and aggregation to the BM [72] (Figure 2). This evidence concerns the gene CD4 and acute myeloid leukemia.