HLA-haploidentical stem cell transplantation after removal of αβ+ T and B cells in children with nonmalignant disorders

Abstract

Twenty-three children with nonmalignant disorders received HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) after ex vivo elimination of αβ+ T cells and CD19+ B cells. The median number of CD34+, αβ+CD3 +, and B cells infusedwas 16.8 × 106, 40 × 103, and 40 × 103 cells/kg, respectively. No patient received any posttransplantation pharmacologic prophylaxis for graft-versus-host disease (GVHD). All but 4 patients engrafted, these latter being rescued by a second allograft. Three patients experienced skin-only grade 1 to 2 acute GVHD. No patient developed visceral acute or chronic GVHD. Cumulative incidence of transplantation-related mortality was 9.3%. With a median follow-up of 18 months, 21 of 23 children are alive and disease-free, the 2-year probability of disease-free survival being 91.1%. Recovery of γδ+ T cells was prompt, but αβ+ T cells progressively ensued over time.Our datasuggest that thisnovelgraftmanipulation strategy is safe and effective for haplo-HSCT. This trial was registered at www.clinicaltrials.gov as #NCT01810120. © 2014 by The American Society of Hematology.