[Lung Function, Lung Clearance Index und Bronchial Inflammation in Children and Adolescents with Bronchiolitis...

Bronchiolitis obliterans (BO) is a rare and severe pulmonary disease which can occur due to airway infection or as a result of stem cell or lung transplantation. Our goal was to study the lung function and airway inflammation among BO patients. Furthermore, we examined the potential of the lung clearance index (LCI) for BO diagnostics among that group.

16 BO patients (age: 16.7; 9.6 - 25.3 years) and 17 healthy controls (age: 16.6; 7.6 - 25.0 years) participated in the study. Lung function parameters (FVC, FEV₁, MEF₂₅, RV und RV/TLC) as well as airway reversibility after administration of 400 µg salbutamol was investigated. The lung clearance index was determined using the multiple-breath washout method (MBW). Additionally, induced sputum was analyzed for cytology and cytokine levels (IL-1ß, IL-6, IL-8, TNF-α) using the cytometric bead array (CBA).

BO patients had significantly lower FVC, FEV₁ and MEF₂₅ but increased RV and RV/TLC. Airway reversibility was observed in 3 patients. The LCI was significantly higher among BO patients compared to the healthy control group (median 10.24 vs. 7.1). Apart from a massive airway inflammation indicated by elevated numbers of total cells and neutrophils, the CBA analysis showed increased levels of IL-6 and IL-8 (p < 0.01).

In BO patients, lung function in childhood and adolescence is severely impaired. Furthermore, we were able to demonstrate the sensitivity and reproducibility of LCI and its value for the evaluation of small airway obstruction. In induced sputum, a neutrophil-dominated airway inflammation is detectable.