Role of Respiratory Viral Infections in Airflow Obstruction After Hematopoietic Cell Transplantation.

BACKGROUND: Respiratory viral infections (RVIs) in allogeneic hematopoietic cell transplant (allo-HCT) recipients can cause airflow obstruction (AFO). Despite this risk, the impact of community-acquired RVI on PFTs in pediatric patients after allo-HCT remains unclear. OBJECTIVE: The study determines the role of RVI in the development of AFO post-transplant among survivors of allo-HCT. STUDY DESIGN: This retrospective study analyzed St. Jude patients undergoing allo-HCT between 2003-2020. AFO was defined by z-scores and forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio expressed as lower limit of normal (LLN). Baseline parameters were obtained before allo-HCT, and Year 1 parameters within 425 days post allo-HCT. Spirometry measures were calculated using the global lung function Initiative (GLI) calculator. Bivariate and multivariate logistic regression identified risk factors for AFO following allo-HCT. RESULTS: A total of 397 patients were included, with a median age of 12.7 years. RVI occurred in 13% of patients within the first 100 days after transplantation. AFO developed in 12% of patients. Among those with AFO, 68% had a baseline FEV1/FVC ratio above the LLN, and 11% had a history of lower respiratory tract infection (LRTI) (p < 0.05). The median time from transplant to RVI was shorter in patients with AFO (12 vs. 34 days). A baseline LLN value was a significant predictor of AFO. However, after adjusting for known covariates, RVI was not independently associated with AFO risk. CONCLUSION: RVIs within 100 days of allo-HCT did not significantly affect AFO following transplant in pediatric patients.