Birgitta Versluijs

111 Respiratory virus infection pre-HCT and alloimmune-mediated lung syndromes consent was obtained in accordance with the Declaration of Helsinki. Institutional ethics committee approval for sample and data collection was obtained through trial numbers 05/143 and 11/063-k. Procedures BAL was performed after achievement of general anesthesia (only if patients had a pro- cedure requiring anesthesia planned [ie, central line placement or HRCT in younger children]) by instilling 10 mL of normal saline aliquots through an endotracheal catheter wedged in the distal bronchi. From 2007, all patients underwent BAL (except for pa- tients who did not have general anesthesia); before 2007, all patients underwent nasal aspiration, but not all had a paired BAL sample taken. Nasal aspiration was done with a disposable catheter connected to a mucous trap. Dry nasopharyngeal suction was perfor- med, followed by instillation and immediate suction of 2 to 3 mL of sterile normal saline through the catheter. Real-time PCR for RVs was performed, as described previously. 8 For detection of RNA viruses, cDNA was synthesized with MultiScribe Reverse Transcriptase and random hexamers (Applied Biosystems, Foster City, Calif ). Detection of viral pathogens was performed in parallel by using real-time PCR assays specific for the following viru- ses: bocavirus; human herpesvirus 6; respiratory syncytial virus; influenzavirus A and B; parainfluenzavirus 1 to 4; rhinoviruses; adenoviruses; human coronaviruses OC43, NL63, and 229E; human metapneumovirus, and Mycoplasma pneumoniae . Semiquanti- tative viral load was expressed in cycle threshold (Ct) values. In case of a positive RV result, we postponed the HCT procedure with 2 weeks in elective HCT (non–primary immunodeficiency benign disorders) and/or we prolonged immu- nosuppressive therapy after HCT as allo-LS prophylaxis. This fits our hypothesis that RV positivity is a predictor for allo-LSs and that steroid treatment for aGVHD has a protec- tive effect on the occurrence of allo-LSs. 6 Apart from the pre-HCT screening, no routine moni-toring for RV was performed. Only in the case of onset/progression of respiratory symptoms was nasal aspiration, BAL, or both repeated. Conditioning regimens were performed according to international protocols. In patients with nonmalignant disease, thus consisted of targeted busulfan (area under the curve, 90 mg h/L in 4 days) and fludarabine (160 mg/m 2 in 4 days). In patients with malignant disease, either fractioned total-body irradiation–based conditioning (3 x 2 x 2 Gy; etopo- side, 60 mg/kg) or targeted busulfan (area under the curve, 90 mg h/L) plus fludarabine (160 mg/m 2 ) or fludarabine plus clofarabine (40 and 120 mg/m 2 ) was given, depending on the patient’s age, myeloid or lymphoid origin of disease, central nervous system invol- vement, and high-risk disease characteristics. In patients receiving an unrelated donor transplant, serotherapy was performed with antithymocyte globulin (thymoglobulin). In 7