Respiratory syncytial virus and other respiratory viruses during the first 3 months of life promote a local TH2-like response.
BACKGROUND
Respiratory syncytial virus (RSV) infections during infancy are considered to be a risk factor for developing asthma and possibly allergic sensitization.


OBJECTIVE
The aim of this study was to investigate the cytokines, chemokines, and eosinophil cationic protein in the nasopharyngeal secretions of infants < or = 7 months of age with RSV infections or other respiratory viral infections and healthy infants as controls. Groups were also analyzed according to age, < or = 3 months and >3 months, and the levels were compared within and between groups.


RESULTS
Thirty-nine infants with RSV, 9 with influenza or parainfluenza virus infections and 50 controls with no history of infections, were enrolled in the study. The RSV-infected infants had significantly higher levels of IL-4; macrophage inflammatory protein 1beta, a chemoattractant for T cells; and eosinophil cationic protein in nasopharyngeal secretions compared with the control group. The levels of the TH2 cytokine IL-4 were significantly higher in RSV-infected infants < or = months of age compared with RSV-infected infants >3 months of age. In infants < or = 3 months of age, infections with influenza or parainfluenza virus caused TH2-like responses similar to those produced by RSV.


CONCLUSIONS
Infections with RSV as well as with influenza and parainfluenza virus during early infancy preferentially promote a TH2-like response in the nose with local production of IL-4, IL-5, and macrophage inflammatory protein 1beta and infiltration and activation of eosinophils.
Kristjansson
Sigurdur
S
Children's Hospital Iceland, Reykjavik, Iceland. sig@landspitali.is
Bjarnarson
Stefania P
SP
Wennergren
Göran
G
Palsdottir
Aslaug H
AH
Arnadottir
Thorgerdur
T
Haraldsson
Asgeir
A
Jonsdottir
Ingileif
I
D000367:Age Factors; D016022:Case-Control Studies; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D047150:Eosinophil Cationic Protein / Q000378:metabolism; D004804:Eosinophils; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000097:blood / Q000276:immunology*; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology* / Q000472:pathogenicity*; D012141:Respiratory Tract Infections / Q000097:blood / Q000276:immunology* / Q000821:virology; D018418:Th2 Cells / Q000276:immunology*
D018925:Chemokines; D016207:Cytokines; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human