Birgitta Versluijs

119 Respiratory virus infection pre-HCT and alloimmune-mediated lung syndromes A B Days after HCT Days after HCT FIGURE 3. A: Probability of TRM for patients with and without allo-LSs. B: Probability of over- all survival (OS) for patients with and without allo-LSs the patients with positive NPA RV results by postponing HCT, prolongation of immuno- suppressive therapy, or both. This might have influenced the study outcomes and could have led to the observed decrease in the incidence of allo-LSs over time. A point of discussion could be the fact that the diagnostic criteria for allo-LSs historically insist on the exclusion of infectious causes. Our data suggest that the presence of an RV in the lower airways is rather a warning sign for the development of allo-LSs. The fact that we have pre-HCT, presymptomatic BAL samples gives new insight in this discus- sion. We show that an RV could be present for weeks (to months) before pulmonary symptoms occur. This is despite the fact that the patients are severely immunocompro- mised. In an era of more precise detection tools (eg, PCR), it is not surprising that certain disease (exclusion) criteria are subject to changes. Therefore we have allowed RV PCR positivity in the definition of allo-LSs. The high incidence of RVs in pediatric HCT recipients is in line with other recent stu- dies. 14-16 The effect of RVs in an HCT population is conflicting. Some groups describe progression to viral pneumonia, 17,18 some describe spontaneous recovery, 15,19 and others describe an association with poor outcome. 6,14,20 Furthermore, there are emerging re- ports on rhinovirus being more than just a common cold virus. 6,14,16,20 p=0.007 p=0.07 Allo-LS  52% (±10) No Allo-LS  20% (±4) No Allo-LS  66% (±4) Allo-LS  48% (±10) 7 0 500 1000 1500 2000 0 1000 2000 3000 4000 1,0 0,8 0,6 0,4 0,2 0,0 1,0 0,8 0,6 0,4 0,2 0,0