Reduced intensity and non-myeloablative allogeneic stem cell transplantation in children and adolescents with malignant and non-malignant diseases.

Allogeneic hematopoietic stem cell transplant (AlloSCT) from related or unrelated histocompatible donors has been well established as potentially curative therapy for children and adolescents with selected malignant and non-malignant diseases. In the malignant setting non-myeloablative (NMA)/reduced intensity (RI)-AlloSCT eradicates malignant cells through a graft versus malignancy effect provided by alloreactive donor T-lymphocytes and/or natural killer cells. In patients with non-malignant diseases NMA/RI AlloSCT provides enough immunosuppression to promote engraftment and correct underlying genetic defects. In children, myeloablative AlloSCT is not only associated with acute short-term toxicities but also long-term late complications such as growth retardation, infertility, and secondary malignancies. NMA/RI-AlloSCT in children may be associated with reduction in use of blood products, risk of infections, transplant-related mortality, and length of hospitalization. Despite the success of RI-AlloSCT in adults, large prospective and/or randomized multicenter studies are necessary in children and adolescent recipients to define the appropriate patient population, optimal conditioning regimens, cost-benefits, survival and differences in short-term and long-term effects compared to conventional myeloablative conditioning. (c) 2007 Wiley-Liss, Inc.