Lethal Pulmonary Complications After Pediatric Allogeneic Hematopoietic Stem Cell Transplantation

Introduction: Hematopoietic stem cell transplantation (HSCT) in children is accompanied by a transplant-related mortality of 10% to 30%, which is the result of lethal pulmonary complications (LPCs) in many cases. Methods: We retrospectively assessed prevalence and risk factors of LPC following 234 allogeneic HSCTs in 228 patients for malignant or nonmalignant diseases at a single institution. Results: Pulmonary complications (PCs) were observed following 81 of 234 transplants (35%). LPCs were observed in 4% of HSCT within 100 days and in 14% within 5 years after HSCT. Late PCs after day 100 were lethal in 56% (22/39) of the patients with PCs, who are 11% (22/202) of all evaluable patients still alive after day +100. Causes of LPC after day 100 were viral (10 cases), bacterial (1 case), fungal (5 cases) pulmonary infection, or noninfectious (6 cases) PCs. Abnormal pretransplant pulmonary function test was not associated with an increased risk of LPC. Children older than 10 years and those undergoing a second HSCT had an increased incidence of overall LPC. T-cell depletion and mismatched donor HSCT (P = 0.001), but not age, were associated with an increased risk of lethal viral pneumonia. Conclusions: Transplant-related mortality up to 5 years after HSCT in children was associated with LPC in 14%. There were more late (> 100 days) than early LPCs, predominantly due to infectious etiologies and affecting children > 10 years of age.