Umbilical cord blood transplantation in children with Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a rare inherited bone marrow failure syndrome characterized by macrocytic anemia and physical malformations. The only available curative treatment for patients with DBA is hematopoietic cell transplantation (HCT). Previous studies have included umbilical cord blood transplantation (UCBT) alongside other graft sources. We conducted a retrospective analysis of 41 pediatric patients with DBA who underwent related or unrelated UCBT between 1994 and 2023, using data from the Eurocord/EBMT registry. Twenty patients received related and 21 received unrelated single UCBT. Most patients received myeloablative conditioning and were transplanted after 1999. In related UCBT, median follow-up was 144.8 months, neutrophil engraftment at day +42 was 100% and 5-year overall survival (OS) was also 100%. In unrelated UCBT, median follow-up was 34 months, neutrophil engraftment at day +42 was 90%, and 5-year OS was 66%. The incidence of acute graft-versus-host disease (GvHD) was considerably higher among unrelated UCBT recipients. The incidence of chronic GvHD was similar between the two cohorts; however, extensive disease was more common after unrelated UCBT. UCBT from an HLA-identical sibling should be considered for DBA patients given the favorable short- and long-term outcomes. For the remaining patients, unrelated UCBT could be considered after individualized risk-benefit assessement.