Host transcription profle in nasal epithelium and whole blood of hospitalized children under 2 years of age with respiratory syncytial virus infection

Abstract

Background. Most insights into the cascade of immune events afer acute respiratory syncytial virus (RSV) infection have been obtained from animal experiments or in vitro models. Methods. In this study, we investigated host gene expression profles in nasopharyngeal (NP) swabs and whole blood samples during natural RSV and rhinovirus (hRV) infection (acute versus early recovery phase) in 83 hospitalized patients <2 years old with lower respiratory tract infections. Results. Respiratory syncytial virus infection induced strong and persistent innate immune responses including interferon signaling and pathways related to chemokine/cytokine signaling in both compartments. Interferon-a/ß, NOTCH1 signaling pathways and potential biomarkers HIST1H4E, IL7R, ISG15 in NP samples, or BCL6, HIST2H2AC, CCNA1 in blood are leading pathways and hub genes that were associated with both RSV load and severity. Te observed RSV-induced gene expression patterns did not differ signifcantly in NP swab and blood specimens. In contrast, hRV infection did not as strongly induce expression of innate immunity pathways, and signifcant differences were observed between NP swab and blood specimens. Conclusions. We conclude that RSV induced strong and persistent innate immune responses and that RSV severity may be related to development of T follicular helper cells and antiviral inflammatory sequelae derived from high activation of BCL6.