Effect of reduced-intensity conditioning and the risk of late-onset non-infectious pulmonary complications in pediatric patients.

Abstract

Late-onset non-infectious pulmonary complications (LONIPCs) contribute to higher morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Therefore, we investigated the risk factors of LONIPCs in pediatric patients. Between 2001 and 2011, 74 pediatric patients (range, 7months to 22.7years old; median 6.5years old), including 29 with a primary immunodeficiency, underwent 80 allo-HSCTs at our institution. Sixty-seven patients who survived more than 3months after allo-HSCT were analyzed retrospectively. The median follow-up period was 1 973days (range, 126-5 145days). Nine patients (13.4%) developed LONIPCs between 90 and 3 578days after allo-HSCT. A myeloablative conditioning (MAC) regimen and chronic GVHD were determined as significant risk factors of LONIPCs. None of 18 patients who received the reduced-intensity conditioning (RIC) regimen developed LONIPCs, although there was no difference in overall survival between the MAC and RIC regimen. Notably, two immunodeficient patients who received busulfan-based MAC regimen under 2years old developed LONIPC with no history of chronic GVHD after 5years and 10years from SCT, respectively, suggesting the direct toxicity of busulfan. Our study's findings indicate that the RIC regimen reduces the risk of LONIPCs in pediatric patients.