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

Twenty-three children with nonmalignant disorders received HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) after ex vivo elimination of alpha beta(+) T cells and CD19(+) B cells. The median number of CD34(+), alpha beta(+)CD3(+), and B cells infusedwas 16.8 x 10(6), 40 x 10(3), and 40 x 10(3) 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 gamma delta(+) T cells was prompt, but alpha beta(+) 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.