Stem cell transplantation for primary immunodeficiency diseases: the North American experience.

PURPOSE OF REVIEW: This review describes recent studies on outcomes after allogeneic hematopoietic cell transplantation for primary immunodeficiency in North America, including severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome and chronic granulomatous disease. RECENT FINDINGS: Using uniform diagnostic criteria, the Primary Immune Deficiency Treatment Consortium described the baseline characteristics of newly diagnosed infants with SCID in North America. Analysis of outcomes of hematopoietic cell transplantation for SCID in North America from 2000 to 2009 showed that young infants, and older infants without active infection, had excellent survival irrespective of type of donor or transplant approach with regard to conditioning. Although pretransplant conditioning with chemotherapy had a clear and strong negative impact on survival in infants with active infection at the time of transplant, among survivors, conditioning was associated with improved immune reconstitution. However, the potential late effects of conditioning in these infants remain to be characterized. Advances in transplant outcomes for Wiskott-Aldrich syndrome and chronic granulomatous disease support the strategy of early transplantation before the onset of severe complications; additional multicenter studies are needed to fully define optimal approaches. SUMMARY: The formation of the Primary Immune Deficiency Treatment Consortium, a multiinstitutional North American consortium, has contributed to our understanding of outcomes after transplant for primary immunodeficiency.