Treatment of Graft Failure After Hematopoietic Stem Cell Transplantation

Inclusion Criteria: * Patients with primary or secondary graft failure, as defined below, may receive a second transplant: * Primary graft failure is defined as not achieving an ANC ≥0.5x10\^9/L for three consecutive days by day 35 - 42 following the first transplant. * Secondary graft failure is defined as achieving an ANC ≥0.5x10\^9/L for three consecutive days by day 35 - 42, but subsequently drops below 0.5x10\^9/L without recovery. * Loss of chimerism is defined as achieving an ANC ≥0.5x10\^9/L for three consecutive, but with less than 10% CD15+ donor cells in the marrow or peripheral blood. * Recipients should have acceptable organ function defined as: * Renal: creatinine \< 2.0 (adults) and creatinine clearance \> 30. For creatinine clearance \< 70, consultation with a BMT pharmacist is necessary for chemotherapy dose adjustments. * Hepatic: bilirubin, AST/ALT, ALP \< 10 x upper limit of normal * Cardiac: left ventricular ejection fraction \> 40% Exclusion Criteria: * Uncontrolled infection at the time of transplant. * Patients with Fanconi Anemia or other DNA breakage syndromes.