Recent advances in haploidentical hematopoietic cell transplantation for pediatric hematologic malignancies

Haploidentical hematopoietic cell transplant (h-HCT) has become the most frequently applied alternate HCT approach. An obvious benefit of h-HCT is that it offers a potential readily available family donor to almost every patient. The application of h-HCT has particularly benefited minority populations who frequently do not find a suitable unrelated donor. Different options exist utilizing either T cell depletion strategies or T cell-replete grafts with myeloablative or reduced intensity conditioning. Graft failures are generally low (<5%) in recent pediatric series with myeloablative regimens. Grade III-IV acute graft-versus-host disease (GvHD) and chronic GvHD have ranged between 7-20% and 5-33%. Patients in remission and those that receive MAC regimens have lower rates of relapse with outcomes comparable to those of matched unrelated transplants and in some studies matched sibling transplants. Research is still needed to determine the optimal donor and graft characteristics, GvHD prophylaxis, and to improve immune reconstitution and control post-HCT infections.