CD34 and acute myeloid leukemia: Consistent with this, when we compared the expansion of cord blood (CB) CD34+ cells cultured with healthy donor MSCs alone (CD34+-alone) or together with AML cell lines (+AML cell lines) for 4 days (Figure 1A), we observed that AML cell lines decreased the retrieval of normal hematopoietic cells by 38% ± 19.5% (Figure 1B).