Unrelated donor marrow transplantation in childhood: a report from the Associazione Italiana Ematologia e Oncologia Pediatrica (AIEOP) and the Gruppo Italiano per il Trapianto Midollo Osseo (GITMO)

BACKGROUND AND OBJECTIVES: Unrelated donor bone marrow transplant (UD-BMT) has become an attractive, alternative source of hematopoietic cells for patients lacking a matched sibling. The aim of this paper is to report on 520 patients below 19 years of age undergoing UD BMT in 31 Italian centers between September 1989 and December 2001, and to focus on the results achieved in the 423 patients grafted before December 2000. DESIGNS AND METHODS: In 1989 the Italian Bone Marrow Transplant Group (GITMO) and the Italian Association for Pediatric Hematology and Oncology (AIEOP) established the Italian Bone Marrow Donor Registry (IBMDR) to facilitate donor search and marrow procurement for patients lacking an HLA identical sibling. By the end of December 2001, 296,720 HLA-A, B typed volunteer donors had been cumulatively registered and 3,411 searches had been activated for Italian patients. At least one HLA-A, B, DRB1 matched donor was found for 54% of the patients and 520 UD BMTs were performed in patients below 19 years of age before December 2001. Since 1999 more than 90% of the patients < or = 14 years old, and more than 50% of the patients 15-18 years old undergoing UD BMT have been treated in AIEOP institutions. In 50% of the cases donors were found in the IBMDR, and in 50% they were found in 14 other Registries. The average time from search activation to transplant was 6 months for diseases other than chronic myeloid leukemia (CML), while for CML it was 8.7 months. RESULTS: Actuarial 100-day transplant-related mortality (TRM) was 32% in patients grafted between 1989 and 1997, and 21% for patients grafted after 1998 (p = 0.003). Twenty-eight per cent of the patients developed grade III or IV acute graft-versus-host disease (GvHD), and 20% developed extensive chronic GvHD. The rate of disease-free survival at three years was 37% for patients with acute lymphoblastic leukemia, 38% for acute myeloid leukemia or myelodysplastic syndrome patients, 59% for patients with inborn errors, and 51% for patients with CML. INTERPRETATION AND CONCLUSIONS: We conclude that the IBMDR has benefited a substantial number of patients lacking a matched sibling and has facilitated the recruitment of UDs into the international donor pool. Results show a positive trend after 1998, mainly due to a decrease in transplant-related-mortality.