title: Elevated Th17 response in infants undergoing respiratory viral infection.
abstract: IL-17 and T-helper (Th)17 cells contribute to viral airway pathology in human newborns. Because umbilical cord blood T cells fail to differentiate toward the Th17 lineage in the presence of autologous antigen-presenting cells, we asked whether Th17 cells are present in young infants that experience respiratory viral infection. To this end, we analyzed tracheal aspirate samples from infant patients suffering from acute respiratory syncytial virus (RSV) infection and healthy infant controls. Acute RSV infection associates with elevated IL-17 and accumulation of CD161(+) T cells in acute RSV infected lungs. Correspondingly, local Th17 polarizing cytokines were increased. In peripheral blood, we show that Th17 cells are absent in healthy 1-month-old infants, but are present in acute RSV patients. The triggering of pathogen-associated pattern receptors TLR4 and TLR7 promotes the generation of a Th17-polarizing cytokine environment by 1-month-old infant dendritic cell (DC). We thus conclude that although Th17 cells are absent in healthy newborns, Th17 cells are present in peripheral blood and the airways of infants that experience viral infection, thereby contributing to airway immunopathology.
authors.affiliation: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Arie J
authors.initials: AJ
authors.lastname: Stoppelenburg
authors.affiliation: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Sytze
authors.initials: S
authors.lastname: de Roock
authors.affiliation: Department of Pediatric Intensive Care, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marije P
authors.initials: MP
authors.lastname: Hennus
authors.affiliation: Departments of Pediatrics and Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Louis
authors.initials: L
authors.lastname: Bont
authors.affiliation: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: m.l.boes@umcutrecht.nl.
authors.forename: Marianne
authors.initials: M
authors.lastname: Boes
mesh_terms: D000328:Adult; D016764:Cell Polarity; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D007223:Infant; D008168:Lung / Q000276:immunology / Q000473:pathology / Q000821:virology; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology* / Q000473:pathology / Q000821:virology*; D012136:Respiratory Syncytial Viruses / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology*; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D016207:Cytokines; D051193:Toll-Like Receptors