Birgitta Versluijs

137 Outcome predictors in Allo-LS in children Allo-immune Lung Syndromes (Allo-LS) Allo-LS were defined as (1) Idiopathic Pneumonia Syndrome (IPS) according to the American Thoracic Society definition: the evidence of widespread lung injury by clini- cal symptoms and radiological abnormalities, in the absence of active lower respiratory infection and other factors explaining pulmonary dysfunction (like cardiac dysfunction, fluid overload or renal failure); 10 (2) Bronchiolitis Obliterans Syndrome (BOS) according to the National Institutes of Health Consensus Criteria on Chronic Graft-versus-Host Disease 2014 as Forced Expiratory Volume in 1 second (FEV1)/Forced Vital Capacity (FVC) < 0.7, FEV1 < 75%, evidence of air trapping (on PFT or HRCT) in the absence of respiratory tract infection. 11 These definitions were adjusted by allowing PCR positivity for Respiratory Viruses (RV) in patients diagnosed with allo-LS, as we previously found that these viruses in BAL (or NPA) were already present in patients before HCT and were found to be an individual predictor for allo-LS. 4,8 When allo-LS was suspected (e.g. new onset of respiratory signs or unforeseen worse- ning of respiratory condition, with a normal temperature and laboratory parameters un- suspicious for infections) patients underwent the following work up: PFT (if feasible, depending on age or respiratory state), chest HRCT, and NPA or BAL. PFT included at least spirometry (FEV1 and FVC), and in some cases body-box measurements (Residual Volume, Total Lung Capacity) and CO-diffusion tests were done. Chest HRCTs were routinely reviewed by the radiologist, looking for signs of infiltrations, air trapping, pleu- ral effusion, pneumothorax etc. A second radiologist examined all the scans to calculate the HRCT composite- and allo-score as described by our group before. 12 BAL and NPA were tested for bacteria (by GRAM stain and culture), fungi (by culture and aspergillus antigen testing) and Respiratory Viruses (by PCR). First line treatment for allo-LS consisted of methylprednisolone (MP) 10 mg/kg/day iv for 3 days and 2 mg/kg/day thereafter, tapering by 25% per week to 0.5 mg/kg/day. MP pulses where repeated monthly until recovery, up to a maximum of 6 pulses. Recovery was defined as normalization of PFT and/or resolved symptoms. In between subsequent MP pulses prednisone 0.5 mg/kg/day was given. For poor responders to MP-pulse the- rapy our protocol prescribes second line therapy of 3-weekly cycles of fludarabine 30 mg/ m2/dose. Other immunosuppressive agents (e.g. cyclosporin) were continued. In addition, azithro- mycin was given because of its suggested immune modulatory effect. 13 In BOS patients, imatinib was added for its known antifibrotic effects. 14 Supportive care was provided with extra oxygen and mechanical ventilation when necessary. Furthermore, because of in- creased immune suppressive treatment antifungal prophylaxis (voriconazol) was added. 8