Open Access

Sophie Walther, Eva Rettinger, Hannah Miriam Maurer, Helena Pommerening, Andrea Jarisch, Jan Sörensen, Ralf Schubert, Martin Berres, Peter Bader, Stefan Zielen, Silvija-Pera Jerkic

• Rationale: Bronchiolitis obliterans syndrome (BOS) is a severe, chronic inflammation of the airways leading to an obstruction of the bronchioles. So far, there are only a few studies looking at the long‐term development of pulmonary impairment in children with BOS. Objective: The objective of this study was to investigate the incidence and long‐term outcome of BOS in children who underwent allogeneic hematopoietic stem cell transplantation (HSCT). Methods: Medical charts of 526 children undergoing HSCT in Frankfurt/Main, Germany between 2000 and 2017 were analyzed retrospectively and as a result, 14 patients with BOS were identified. A total of 271 lung functions (spirometry and body plethysmography), 26 lung clearance indices (LCI), and 46 chest high‐resolution computed tomography (HRCT) of these 14 patients with BOS were evaluated. Results: Fourteen patients suffered from BOS after HSCT (2.7%), whereby three distinctive patterns of lung function impairment were observed: three out of 14 patients showed a progressive lung function decline; two died and one received a lung transplant. In five out of 14 patients with BOS persisted with a severe obstructive and secondarily restrictive pattern in lung function (forced vital capacity [FVC] < 60%, forced expiratory volume in 1 second [FEV1] < 50%, and FEV1/FVC < 0.7) and increased LCI (11.67‐20.9), six out of 14 patients recovered completely after moderate lung function impairment and signs of BOS on HRCT. Long‐term FVC in absolute numbers was increased indicating that the children still have lung growth. Conclusion: Our results showed that the incidence of BOS in children is low. BOS was associated with high mortality and may lead to persistent obstructive lung disease; although, lung growth continued to exist.