Birgitta Versluijs

115 Respiratory virus infection pre-HCT and alloimmune-mediated lung syndromes Most patients had no or very mild signs of a URTI and no signs of lower respiratory tract infection at the time of sampling. The median PCR Ct value for RV in BAL fluid was 32 (range, 17-43), which is comparable with the Ct values found in NPAs (29; range, 14-43). Outcomes of interest During conditioning and early after HCT, the URTI symptoms did not progress to significant lower respiratory tract infection symptoms. On the contrary, most patients recovered spontaneously. Twenty-four (13%) patients were given a diagnosis of an allo-LS after a median of 159 days (range, 7-201 days). Fifteen patients had IPS, and 9 patients had BOS. In multivariate analysis detection of RV in BAL fluid was the only predictor associated with allo-LSs (hazard ratio [HR], 3.8; 95% CI, 1.4-10.7; P = .01), as shown in Table 3 (see Table S1 for univariate analysis). When subdividing into groups with BOS and those with IPS, similar results were found. RV detection in BAL fluid was a predictor for BOS (HR, 5.1; 95% CI, 1.1-24.7; P = .04; see Tables S2 and S3 and Figure S1). For patients with IPS, a positive BAL fluid RV result (HR, 3.6; 95% CI, 1.0-13.8; P = .06) was a borderline significant predictor, as was having an inborn error of metabolism as the indication for transplantation (HR, 3.6; 95% CI, 1.0-12.8; P = .05; see Tables S4 and S5 and Figure S2). TABLE 2. Distribution of respiratory viruses in pre-HCT samples. NPA only N=36 BAL fluid only N=74 Rhinovirus 14 (39%) 38 (51%) Multiple viruses 10 (28%) 20 (27%)* Parainfluenzavirus 4 (10%) 4 (6%) Adenovirus 3 (8%) 2 (3%) Coronavirus 2 (6%) 6 (9%) Respiratory syncytial virus 1 (3%) 1 (1%) Bocavirus 2 (6%) 1 (1%) Influenzavirus — 1 (1%) Human metapneumovirus — 1 (1%) * Multiple: 2 to 4 different respiratory viruses, 14 with rhinovirus. 7