- Recipients receiving matched related or unrelated donors will receive 4 days of chemotherapy with busulfan and fludarabine to suppress their immune system and prepare them for the transplant. Donors receiving haploidentical related donors will receive two doses of chemotherapy with cyclophosphamide, 5 days of fludarabine, 3 days of busulfan, and one dose of radiation to suppress their immune system and prepare them for the transplant.