Abstract
•The study is a retrospective single center analysis of alemtuzumab/300 cGy total body irradiation (TBI) matched sibling donor peripheral blood hematopoietic cell transplantation for sickle cell disease.•No graft rejection or graft-versus-host disease occurred in 16 patients.•Long-term follow-up for sustained engraftment and late effects of TBI is important.
Sickle cell disease is a potentially debilitating hemoglobinopathy associated with early mortality. The only established curative therapy is hematopoietic cell transplantation (HCT) with a matched sibling donor. The National Institutes of Health nonmyeloablative regimen of alemtuzumab/300 cGy total body irradiation and prolonged sirolimus exposure for graft-versus-host disease (GVHD) prophylaxis was administered to 16 children and adolescents. Infused products were unmanipulated granulocyte colony stimulating factor mobilized peripheral blood stem cells. All patients achieved mixed donor-recipient engraftment with no cases of secondary graft failure to date. Two patients have donor myeloid chimerism in the range of 30% to 40%. No sickling crises post-HCT have been observed. Event-free and overall survival rates are 100% with median follow-up of 19.5 months. No cases of GVHD have been observed. Sirolimus weaning was possible in all but one eligible patient to date. Ongoing follow-up and a larger prospective clinical trial are required to determine the long-term safety and efficacy of this regimen in children.