Birgitta Versluijs

46 Patients and methods Pulmonary function tests Because performing pulmonary function tests (PFTs) is difficult in young children, in our cohort routine PFTs before transplantation were performed only in children aged ≥6 years. PFTs also were performed in all children with such respiratory symptoms as short- ness of breath, dry cough, and tachypnea after discharge. In patients with a diagnosis of allo-LS, PFTs were repeated at least monthly until the disorder resolved. Patients aged ≥6 years underwent spirometry testing and, when technically possible, body plethysmograp- hy and COdiffusion testing according to European Respiratory Society guidelines. 22 Total lung capacity (TLC) and forced expiratory volume in 1 second (FEV1) were expressed as percentage of the predicted normal value, using published equations for children and adults, 23 giving TLC % predicted and FEV1 % predicted. A TLC % predicted of <80% was designated a ‘‘restrictive’’ pattern; an FEV1 % predicted of <80% and FEV1/forced vital capacity (FVC) of <70%, an ‘‘obstructive’’ pattern; a TLC% predicted of <80% and FEV1/ FVC of <70%, a ‘‘mixed’’ pattern; and CO diffusion of <80%, ‘‘impaired diffusion.’’ Definitions of disease URTI was defined as rhinorrhea and/or dry cough only. LRTI/pneumonia was defined as cough and/or fever and pulmonary infiltrates on chest x-ray, with elevated C-reactive protein and/or positive microbiological cultures from sputum, BAL fluid, or blood. IPS was defined as the presence of acute bilateral pulmonary infiltrates with cough, dyspnea, and hypoxemia in the absence of infection (excluding an RV) or heart failure. By this de- finition, IPS included such entities as diffuse alveolar bleeding and periengraftment syn- drome. 2 BOS was defined as typical HRCT changes, such as bronchial wall thickening, air trapping, and mosaic parenchymal attenuation 1 , in the absence of signs of infection and, whenever pulmonary function testing could be done, abnormal pulmonary func- tion test results (ie, decrease in FEV1 of >20% or in FEV1/FVC of <70%). bronchiolitis obliterans organizing pneumonia (BOOP) was defined as restrictive PFT (if PFT were done) and consolidation on chest x-ray. 1 Allo-LS was defined as IPS, BOS, and BOOP, subdivided into acute (IPS) and chronic (BOS/BOOP) forms. Treatment of lung disease In general, URTI was not treated; only in the 2 patients with influenza A was a neu- raminidase inhibitor administered. LRTI/pneumonia was treated with empiric antibiotic therapy (vancomycin and ceftazidime). Whenever a bacterial pathogen was found, the- rapy was adjusted according to antibiotic resistance. In patients with probable or proven Aspergillus spp, voriconazole was administered; if no response to voriconazole was noted (progressive clinical or radiologic findings), granulocyte transfusions were given. Allo-LS was treated with MP 10 mg/kg/day i.v. for 3 days and 2 mg/kg/day thereafter, tapering by 25% per week to 0.5 mg/kg/day. The MP pulses were repeated every 4 weeks 3