Allogeneic hematopoietic stem cell transplantation (allo-HSCT)is the only therapeutic option for many hematological malignancies. Unfortunately, about 75% of patients who require allo-HSCT lack human leukocyte antigen (HLA)-matched donors. The alternative is hematopoietic stem cells from an HLA-mismatched family donor. However, this strategy, which is called haploidentical HSCT, may be associated with high risk of early death and severe GVHD.