Early Use of Tacrolimus in HLA-Mismatched Haploidentical Allogeneic Hematopoietic Transplantation With Post-Transplant Cyclophosphamide

Inclusion Criteria: * Availability of a 5/10-8/10 mismatched (HLA-A, B, DR) haploidentical related donor with a negative HLA cross-match in the host vs. graft direction and willing to provide peripheral blood stem cells * Karnofsky status \>/= 70% * Hematologic malignancy requiring allogeneic transplantation * First allogeneic transplant only. Prior autologous transplant is allowed. Exclusion Criteria: * Poor cardiac function: LVEF \<40% * Poor pulmonary function: FEV1 and FVC \<50% predicted * Poor liver function: bilirubin \>/= 3mg/dL (not due to hemolysis, Gilbert's or primary malignancy) * Poor renal function: Creatinine \>/= 2mg/dL or creatinine clearance (calculated or measured creatinine clearance is permitted) \<40mL/min based on Traditional Cockcroft-Gault formula * Women of childbearing potential who currently are pregnant or who are not practicing adequate contraception * Patients who have any debilitating medical or psychiatric illness that would preclude their giving informed consent or their receiving optimal treatment and follow up