Reduced intensity transplantation for primary immunodeficiency disorders.

Many advances have been made since the first successful hematopoietic cell transplants (HCT) in children with primary immunodeficiency disorders (PID) were reported 40 years ago, and many children with PID can now be cured from their otherwise lethal disorders through well-matched HCT procedures. Preexisting morbidity and infection remain the principal adverse factors for poor outcomes with HCT. To improve current results, earlier diagnosis, well-tolerated pretransplant conditioning regimens, and promotion of immune reconstitution need to be considered. This article addresses modifications in the conditioning regimen that might lead to further improvement in HCT outcomes.