Ruggeri, AnnalisaEapen, MaryScaravadou, AndromachiCairo, Mitchell SBhatia, MonicaKurtzberg, JoanneWingard, John RFasth, AndersLo Nigro, LucaAyas, MouhabPurtill, DuncanBoudjedir, KarimChaves, WagnaraWalters, Mark CWagner, JohnGluckman, ElianeRocha, VandersonEurocord RegistryCenter for International Blood and Marrow Transplant ResearchNew York Blood Center2022-03-232022-03-232011-091083-87911523-6536https://hdl.handle.net/10161/24672We examined the efficacy of unrelated cord blood (CB) transplantation in children with thalassemia (n = 35) and sickle cell disease (n = 16), using data reported to 3 registries. Donor-recipient pairs were matched at HLA-A and -B (antigen level) and DRB1 (allele level) in 7 or HLA mismatched at 1 (n = 18), 2 (n = 25), or 3 loci (n = 1). Transplant conditioning was myeloablative (n = 39) or reduced intensity (n = 12). Neutrophil recovery with donor chimerism was documented in 24 patients; 11 patients developed grade II-IV acute graft-versus-host disease (aGVHD) and 10 patients, chronic GVHD (cGVHD). Overall survival (OS) and disease-free survival (DFS) were 62% and 21% for thalassemia and 94% and 50% for sickle cell disease (SCD), respectively. In multivariate analysis, engraftment rate (hazard ratio [HR] 2.2, P = .05) and DFS (HR 0.4, P = .01) were higher with cell dose >5 × 10(7)/kg. The 2-year probability of DFS was 45% in patients who received grafts with cell dose >5 × 10(7)/kg and 13% with lower cell dose. Primary graft failure was the predominant cause of treatment failure occurring in 20 patients with thalassemia and 7 patients with SCD. Primary graft failure was fatal in 5 patients with thalassemia. These results suggest that only CB units containing an expected infused cell dose >5 × 10(7)/kg should be considered for transplantation for hemoglobinopathy.Eurocord RegistryCenter for International Blood and Marrow Transplant ResearchNew York Blood CenterNeutrophilsTransplantation ChimeraHumansAnemia, Sickle CellThalassemiaGraft vs Host DiseaseHistocompatibility TestingTreatment OutcomeTransplantation ConditioningCord Blood Stem Cell TransplantationCell CountRegistriesSurvival AnalysisGraft SurvivalChildFemaleMaleJournal article2022-03-23