title: Virus infection and allergy in the development of asthma:  what is the connection?
abstract: OBJECTIVE
  Information is accumulating which implicates airway inflammation resulting from respiratory viral infections, acting against a background of atopy, in both the cause and pathogenesis of atopic asthma. This review brings together the most recent publications relevant to this rapidly evolving area, particularly those focusing on underlying pathogenic mechanisms.
  
  
  RESULTS
  Salient findings from the recent literature include increased respiratory infection-associated symptom severity/duration and loss of asthma control in atopic relative to nonatopic children; up-regulation of FcεR1 expression on circulating monocytes/dendritic cells occurs during virus-associated atopic asthma exacerbations, providing a mechanism for transient amplification of underlying allergic airways inflammation; high potency of hRV-type C in induction of infection-associated wheeze; Th2-polarized immunity to mucosal dwelling bacteria and protection against asthma; a role for IL-15 in viral-associated airways inflammation; vitamin D and protection against infection-associated asthma exacerbations; strategies for reduction of infection-associated wheezing severity by boosting mucosal Treg cell activity via immunostimulation of the gut mucosa.
  
  
  CONCLUSIONS
  Research in this area is pointing towards new rationales for development of early intervention strategies for prevention of asthma initiation and progression in childhood, based on control of respiratory infections and/or sensitization to aeroallergens.
authors.affiliation: Telethon Institute for Child Health Research, and Centre for Child Health Research, The University of Western Australia, Perth, Australia. patrick@ichr.uwa.edu.au
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Holt
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Strickland
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
mesh_terms: D000082:Acetaminophen / Q000009:adverse effects / Q000276:immunology; D001249:Asthma / Q000276:immunology / Q000821:virology*; D001424:Bacterial Infections / Q000150:complications / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000821:virology*; D019409:Interleukin-15 / Q000276:immunology; D012141:Respiratory Tract Infections / Q000150:complications / Q000276:immunology / Q000382:microbiology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000821:virology; D014777:Virus Diseases / Q000150:complications* / Q000453:epidemiology / Q000276:immunology; D014807:Vitamin D / Q000494:pharmacology
chemical_list: C569274:IL15 protein, human; D019409:Interleukin-15; D014807:Vitamin D; D000082:Acetaminophen