Haploidentical transplants using ex vivo T-cell depletion

Allogeneic hematopoietic stem cell transplantation (HSCT) is the best post-remission therapy for patients with acute leukemia (AL) at high risk of relapse. Advantages of having a family member as donor include: no undue delay in obtaining the graft; choice of best donor with regards to natural killer (NK) alloreactivity and cytomegalovirus (CMV) status from a panel of candidate family members; easy access to post-transplant cellular therapies like donor lymphocyte infusions and opportunity for a second graft from the original donor, or another family member in case of graft failure. This review will explore how the biological obstacles to HLA-haploidentical (haplo)-HSCT were overcome and how transplant modalities have evolved over time to potentiate the graft-versus-leukemia (GvL) effect in the absence of graft-versus-host disease (GvHD).