Breastfeeding is associated with the production of type I interferon in infants infected with influenza virus.
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.
Melendi
Guillermina A
GA
Fundacion INFANT, Buenos Aires, Argentina.
Coviello
Silvina
S
Bhat
Niranjan
N
Zea-Hernandez
Johanna
J
Ferolla
Fausto M
FM
Polack
Fernando P
FP
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
D007370:Interferon Type I; D012333:RNA, Messenger
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