¹Oncoematologia Pediatrica, IRCCS Policlinico San Matteo, Università di Pavia, Italy

²Clinica Pediatrica, Università di Padova, Italy

³Clinica Pediatrica, Ospedale Sant'Orsola, Università di Bologna, Italy

⁴Divisione di Ematologia e Oncologia, Istituto G Gaslini, Genova, Italy

⁵Registro Italiano Donatori di Midollo Osseo, Ospedali Galliera, Genova, Italy

⁶Clinica Pediatrica, Ospedale Nuovo S Gerardo, Monza, Italy

⁷Clinica Pediatrica, Università di Torino, Italy

⁸Clinica Pediatrica, Università di Pisa, Italy

⁹Clinica Pediatrica, Spedali Civili, Università di Brescia, Italy

Correspondence to: F Locatelli, Oncoematologia Pediatrica, Università di Pavia, IRCCS Policlinico San Matteo, Ple Golgi 2, I-27100 Pavia, Italy; Fax: +39-0382-501.251

Aims of this study were to verify whether reduction in transplant-related mortality (TRM) of children with acute lymphoblastic leukemia (ALL) in second complete remission (CR) given allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated volunteers has occurred over time and to investigate the role of other variables on the probabilities of relapse, TRM and event-free survival (EFS). We compared results obtained in 26 children given HSCT before January 1998 with those of 37 patients transplanted beyond that date. In all donor-recipient pairs, histocompatibility was determined by serology for HLA-A and -B antigens and by high-resolution DNA typing for DRB1 antigen. High-resolution molecular typing of HLA class I antigens was employed in 20 of the 37 children transplanted more recently. Probability of both acute and chronic GVHD was comparable in the two groups of patients. In multivariate analysis, children transplanted before January 1998, those with T-lineage ALL and those experiencing grade II-IV acute GVHD had a higher relative risk of TRM at 6 months after transplantation. Relapse rate was unfavorably affected by a time interval between diagnosis and relapse <30 months. The 2-year probability of EFS for children transplanted before and after 1 January 1998 was 27% (10-44) and 58% (42-75), respectively (P = 0.02), this difference remaining significant in multivariate analysis. EFS of unrelated donor HSCT in children with ALL in second CR has improved in the last few years, mainly due to a decreased TRM. This information is of value for counseling of patients with relapsed ALL.

Leukemia (2002) 16, 2228-2237. doi:10.1038/sj.leu.2402690

unrelated donor stem cell transplantation; unrelated donor registries; acute lymphoblastic leukemia; GVHD; leukemia relapse; HLA typing