Pulmonary Function in Pediatric survivors of non-Malignant Disorders after Allogeneic Hematopoietic Stem Cell Transplantation.

Allogeneic hematopoietic stem cell transplantation (HSCT) is used to treat children with non-malignant disorders. As the number of survivors of non-malignant disorders after allogeneic HCST rises, monitoring late sequelae becomes increasingly important. However, no studies have solely targeted this population especially on pulmonary function. We therefore performed a long-term prospective study of pulmonary function in 38 pediatric survivors of non-malignant disorders after allogeneic HCST, including aplastic anemia (n = 15), sickle cell anemia (n = 13), immunodeficiency syndromes (n = 8), Hurler syndrome (n = 1), and osteopetrosis (n = 1). A total of 260 pulmonary function tests were conducted on the patients. Older age of recipients was associated with poorer pulmonary function; lower ratio of forced expiratory volume in 1 second and forced vital capacity (FEV₁/FVC; p < 0.0001); lower percent predictives in FEV₁ (p = 0.0178), forced expiratory flow (FEF_25–75%; p < 0.0001), FVC (p = 0.0299), and diffusion capacity corrected for hemoglobin (DLCO_corr; p = 0.0079); higher ratio of residual volume and total lung capacity (RV/TLC; p = 0.0193); and higher percent predictives in RV (p = 0.0308) and functional residual capacity (FRC; p = 0.0489). The following percent predictive values declined over time (median follow-up: 8 years): FEF_25–75% (p = 0.0064), RV (p = 0.0134), FRC (p = 0.003), FVC (p = 0.0004), TLC (p = 0.0248), and DLCO_corr (p = 0.0077). Also, busulfan use was associated with lower FEV₁ (p = 0.026), FVC (p = 0.0194), and DLCO_corr (p = 0.0105). This study underscores the need to monitor risk-adapted long-term lung function and provide early interventions in this vulnerable population, especially for those who received HSCT at an older age or had been administered busulfan.