What makes a pediatric or young adult patient an appropriate transplant candidate?

A 3-year-old child with chronic granulomatous disease was brought to the transplant clinic by his parents. The patient has a history of Aspergillus fumigatus pneumonia, which required mechanical ventilation, and sepsis, resulting in several intensive care stays. He has failure to thrive and developmental delay. His parents are seeking guidance whether allogeneic hematopoietic cell transplantation (HCT) is a reasonable treatment option given concerns about his upfront major health limitations. Based on the original HCT-Comorbidity Index (CI), this child's risk for nonrelapse mortality (NRM) would be negligible with a score of 0. With use of the validated youth-nonmalignant HCT-CI, the score increases to 5, due to prior mechanical ventilation (+3), history of fungal infection (+1), and being underweight (+1), with at least 2-fold increase in risk of NRM. The role of developmental delay is unclear and not currently validated to prognosticate survival. While HCT was ultimately recommended in this case, the family was counseled to have a more realistic sense of NRM risk.