title: Innate immune dysfunction is associated with enhanced disease severity in infants with severe respiratory syncytial virus bronchiolitis.
abstract: BACKGROUND
  Most patients with respiratory syncytial virus (RSV) bronchiolitis requiring admission to the pediatric intensive care unit (PICU) have no risk factors for severe disease. We sought to investigate the relationship between serum cytokine concentrations, innate immune responsiveness, and RSV disease severity.
  
  
  METHODS
  Previously healthy infants (median age, 2.6 months) with RSV bronchiolitis (PICU, n = 20; floor, n = 46) and healthy matched controls (n = 14) were enrolled, and blood samples were obtained within 24 hours of admission to measure plasma tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin 10 (IL-10) concentrations and, whole blood lipopolysaccharide-stimulated cytokine production capacity.
  
  
  RESULTS
  Plasma IL-6, IL-8, and IL-10 concentrations were comparable between PICU and floor patients, but higher than in healthy controls (P < .05). In contrast, TNF-α, IL-6, and IL-8 production capacity was significantly decreased in PICU compared with both floor patients and healthy controls. In adjusted analyses, only impaired TNF-α and IL-8 production capacity were associated with longer length of stay (P = .035) and greater disease severity scores (P = .001).
  
  
  CONCLUSIONS
  Infants with severe RSV bronchiolitis had increased plasma cytokine concentrations and yet impaired innate immunity cytokine production capacity, which predicted worse disease outcomes. Immune monitoring of otherwise healthy infants with RSV lower respiratory tract infection could help identify patients at risk for severe disease at the time of hospitalization.
authors.affiliation: Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, The Ohio State University School of Medicine, Columbus, OH 43205, USA.
authors.forename: Cesar
authors.initials: C
authors.lastname: Mella
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Suarez-Arrabal
authors.forename: Santiago
authors.initials: S
authors.lastname: Lopez
authors.forename: Julie
authors.initials: J
authors.lastname: Stephens
authors.forename: Soledad
authors.initials: S
authors.lastname: Fernandez
authors.forename: Mark W
authors.initials: MW
authors.lastname: Hall
authors.forename: Octavio
authors.initials: O
authors.lastname: Ramilo
authors.forename: Asuncion
authors.initials: A
authors.lastname: Mejias
mesh_terms: D001990:Bronchiolitis, Viral / Q000276:immunology* / Q000503:physiopathology* / Q000821:virology; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007223:Infant; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000503:physiopathology / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000276:immunology / Q000472:pathogenicity*; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D016207:Cytokines; D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha