LCI and Bronchial Inflammation in Patients With BO

The investigators here compare lung function parameters (RV, RV/TLC and FEF75) with the results of the Lung Clearance index (LCI) . Further this study evaluates bronchial inflammatory markers in 20 patients with bronchiolitis obliterans at the age of 6 to 28 years compared with an age- and sex-matched control group. The investigators will perform a pulmonary function test (body plethysmography with DLCO) and compare the results with the LCI. Further we will measure the fraction of exhaled nitric oxide (FeNO) and draw a blood sample to determine the level of systemic inflammation. Finally induced sputum is collected and a cell count is performed, and cells and supernatants are analyzed for inflammatory markers. This study will set baseline markers for future interventional studies.