Megadose of hematopoietic stem cells for haploidentical transplants

Abstract

Studies in mice and humans demonstrate that transplantation of hematopoietic progenitors in numbers larger than commonly used (“megadose” transplants) overcomes major genetic barriers without induction of graft-versus-host disease. Therefore, transplantation from a human leukocyte antigen mismatched family member is a viable option for patients with acute leukemia at high risk of relapse who urgently need a transplant and who do not have a well matched unrelated donor. In vitro studies suggest that veto cells, contained in the population of hematopoietic progenitors, facilitate this favorable outcome. Future developments may extend the full-haplotype mismatched transplant to the elderly who cannot withstand highly intensive conditioning, patients with counter indications for intensive radiotherapy or chemotherapy and patients with nonmalignant hematological disorders in whom the current transplant related mortality rates are unacceptable.