Haploidentical transplantation for leukemia

Hematopoietic stem cell transplantation from human leukocyte antigen (HLA)-haploidentical family members offers a potential cure for patients in need of allogeneic immunotherapy who have no immediate access to an HLA-matched donor. The use of ex vivo T-cell-depleted stem cells combined with immuno-myeloablative conditioning has enabled durable donor engraftment with a low incidence of acute graft-versus-host disease despite the HLA disparity. Moreover, additional transplant techniques involving in vivo T-cell depletion and reduced-intensity conditioning have further minimized the risks. However, a major drawback is delayed immune reconstitution leading to infections and high relapse rates, prompting significant research efforts focused on improving recovery in the post-transplant period. Infusions with donor lymphocytes are common, though newer manipulations with a focus on donor natural killer cells hold great promise, as do other modified donor T-cell infusions. Success of these new procedures will make haploidentical transplants safer and more effective, further broadening its appeal.