Treatment of childhood leukemia with unrelated donor allogeneic bone marrow transplantation

OBJECTIVE: Allogeneic bone marrow transplantation has been established as a standard method for the treatment of a range of malignant and non-malignant hematologic diseases in children. Unfortunately, fewer than 30% of patients have a human leukocyte antigen (HLA)-matched sibling. Advances in our understanding of the HLA system and the development of large international donor registries encourage the increasing use of unrelated donors as an alternative source of stem cells. The purpose of this study was to evaluate the clinical efficacy and safety of unrelated donor allogeneic bone marrow transplantation (URD-BMT) for the treatment of childhood leukemia. METHODS: Six patients with leukemia received URD-BMT. Two of them suffered from chronic myeloid leukemia (CML), 3 suffered from acute lymphocytic leukemia (ALL) and 1 suffered from acute promyelocytic leukemia (APL) (CR2). All cases were facilitated by Tzu Chi Marrow Donor Registry (TCTMDR). The high resolution DNA test for classIand II was carried out in HLA typing of all donor-receiver pairs. HLA allele matched in three cases, mismatched with one locus in two cases and with two loci in one case. All patients were prepared with cyclophosphamide (CY) 60 mg/kg/day for 2 days (total dose 120 mg/kg) and busulfan (Bu) 1 mg/kg x 4/day for 4 days (total dose 16 mg/kg). Mycophenolate mofetil (MMF), CsA and MTX were given to prevent acute graft-versus-host-disease (aGVHD). CsA of 3 mg/kg/d was continuously given by i.v. infusion, and then 6mg/kg/d by oral. The blood CsA concentration was 200 - 300 ng/ml. MTX was given at the dosage of 15 mg/m(2) on d 1 and 10 mg/m(2) on d 3, 6,9 or 11. MMF was given at the dosage of 0.25 - 0.5 g/d from day 0 to day 120. Prostaglandin E1 was given to prevent the hepatic veno-occlusive disease (VOD), Ganciclovir was used to prevent CMV infection until the CMV antigenemia became negative. RESULTS: Analysis of DNA short tandem repeats showed total engraftment of donor marrow after transplantation in all cases. The median time when granulocyte exceeded 0.5 x 10(9)/L was 14.5 (13 - 18) days, platelets exceeded 20 x 10(9)/L was 16 (14 - 23) days. The acute GVHD grade II-IV occurred in 2 of 6 (33.3%) patients. There were 3 cases with chronic GVHD and none of them developed with the extensive chronic GVHD. All patients were alive in disease-free situation now with median follow-up 412 (187 - 1338) days. CONCLUSION: URD-BMT is an effective method for the treatment of childhood leukemia.