Tolerance induction by ‘megadose’ transplants of CD34+ stem cells: a new option for leukemia patients without an HLA-matched donor

Early studies in murine models and more recent clinical data in heavily pre-treated leukemia patients have shown that escalation of the dose of hematopoietic progenitor cells can overcome major genetic barriers and enable rapid and durable engraftment of haploidentical, three-locus-mismatched transplants without graft-versus-host disease. In vitro studies suggest that veto cells within the progenitor population most probably mediate this facilitating effect.