Reduced intensity haemopoietic stem-cell transplantation for treatment of non-malignant diseases in children.

Transplantation of allogeneic haemopoietic stem cells can cure several non-malignant disorders in children. Transplantation with reduced intensity preparation might achieve the same goals but with less toxicity. We undertook a pilot study to determine engraftment rates, kinetics of engraftment, toxicity, and acute graft-versus-host disease (GVHD) associated with a uniform reduced intensity haemopoietic stem-cell transplant (HSCT) regimen for children with non-malignant diseases. We studied 13 paediatric patients with non-malignant disorders who underwent reduced intensity HSCT at Children's Memorial Hospital from January, 2000, to February, 2004. Stem-cell sources included unrelated donor, matched-sibling peripheral blood stem cells, and unrelated cord blood. A uniform preparative regimen was used, consisting of fludarabine, busulfan, and anti-thymocyte globulin. Major endpoints were engraftment, transplant-related mortality at day 100, short-term toxicities, and incidence of acute GVHD. 72% of evaluable patients achieved full donor engraftment. There was rapid reconstitution of platelets (median 13.5 days) and neutrophils (median 18 days). Short-term toxicities were minimal, as seen by a median length of hospital stay of 7 days (between days 0-100). Incidence of grade II-IV acute GVHD was 8%. Two patients died before day 100 from underlying disease and viral infection, respectively (day 100 transplant-related mortality of 15%). The 1-year overall survival was 84% (95% CI 64-100). Most patients with immunodeficiencies and metabolic disorders had excellent donor engraftment and disease resolution or stabilisation, but most of those with haemoglobinopathies rejected their graft. This reduced intensity regimen followed by HSCT provides a good alternative to myeloablative HSCT for children with non-malignant disorders, except for haemoglobinopathies, in which engraftment is poor. Even patients with unrelated donor haemopoietic stem-cell transplants had adequate engraftment with acceptable toxicities.