Reduced Intensity Fludarabine and TBI Prior to Haplo-Identical Transplantation

Inclusion Criteria: * Availability of 3/6 - 5/6 matched related donor with a negative HLA-cross match in the host vs. graft direction willing to donate peripheral blood stem cells * KPS \>/= 70% * Hematologic malignancy requiring allogeneic transplantation, with a predicted high risk of relapse following non-myeloablative, low intensity conditioning. Exclusion Criteria: * Poor cardiac function (LVEF \<45%) * Poor pulmonary function (FEV, FVC, DLCO \<60%) * Poor liver function (bilirubin \>/= 2.5mg/dL; AST or ALT \>3xULN) * Poor renal function (creatinine clearance \<40mL/min) * HIV-positive; active HepB or HepC * Uncontrolled infection * Pregnant female or not able to practice adequate contraception * Debilitating medical or psychiatric illness which would preclude their giving informed consent