title: Breastfeeding is associated with the production of type I interferon in infants infected with influenza virus.
abstract: BACKGROUND
  Breast milk-mediated protection against respiratory viruses is well established. However, protective mechanisms are unclear. Type I interferons (IFN) mediate host defence against respiratory viruses, particularly influenza virus. The relationship among type I IFN, respiratory viral infections and breastfeeding has not been explored.
  
  
  METHODS
  Type I IFN responses were studied by ELISA and real time PCR in nasal secretions of infants experiencing their first respiratory infection. Modulation of IFN by breastfeeding and other variables affecting severity during viral infection was explored.
  
  
  RESULTS
  One hundred and twenty infants were positive by RT-PCR for influenza virus (n = 24), human metapneumovirus (hMPV) (n = 30) or respiratory syncytial virus (RSV) (n = 66). Type I IFNs were detected more frequently in infants infected with influenza virus than in those infected with RSV or hMPV. Breastfeeding promoted higher rates and levels of type I IFN only in infants infected with influenza virus. No effect on IFN production was observed for age, gender or smoking.
  
  
  CONCLUSIONS
  Our study confirms that type I IFN production is detected more frequently in infants infected with influenza virus. Importantly, higher rates and levels of type I IFN in these infants are associated with breastfeeding. These observations suggest that breast milk can protect against respiratory viruses by activating innate antiviral mechanisms in the host.
authors.affiliation: Fundacion INFANT, Buenos Aires, Argentina.
authors.forename: Guillermina A
authors.initials: GA
authors.lastname: Melendi
authors.forename: Silvina
authors.initials: S
authors.lastname: Coviello
authors.forename: Niranjan
authors.initials: N
authors.lastname: Bhat
authors.forename: Johanna
authors.initials: J
authors.lastname: Zea-Hernandez
authors.forename: Fausto M
authors.initials: FM
authors.lastname: Ferolla
authors.forename: Fernando P
authors.initials: FP
authors.lastname: Polack
mesh_terms: D001942:Breast Feeding; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007118:Immunoassay; D007223:Infant; D007251:Influenza, Human / Q000276:immunology / Q000378:metabolism*; D007370:Interferon Type I / Q000276:immunology / Q000378:metabolism*; D008297:Male; D029121:Metapneumovirus; D008895:Milk, Human / Q000276:immunology*; D009297:Nasal Mucosa / Q000821:virology; D018184:Paramyxoviridae Infections / Q000276:immunology / Q000378:metabolism; D011446:Prospective Studies; D012333:RNA, Messenger / Q000378:metabolism; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000378:metabolism
chemical_list: D007370:Interferon Type I; D012333:RNA, Messenger
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