title: Developmental immunology: clinical application to allergy-immunology.
abstract: BACKGROUND
  An increase in prevalence of allergic diseases has been seen at an unprecedented rate in many countries throughout the world. Associated with this increase in allergic disease has been a disturbing increase in morbidity and mortality of such diseases as asthma despite the availability of several new therapeutic agents over the past 2 to 3 decades. The search for both environmental factors, eg, new allergens, as well as biologic markers of genetic susceptibility, eg, respiratory viruses, has yielded considerable promise for an explanation for this rising prevalence of allergic disease.
  
  
  OBJECTIVE
  To present a central unifying hypothesis based upon recent knowledge concerning the developing human immune system and its interaction with external environmental factors, particularly viral infections, as a basis for a clearer understanding of the changing faces of the allergic diseases throughout the lifespan of the individual.
  
  
  METHODS
  English language articles were selected from PubMed, as well as selected abstracts that would have immediate, practical clinical implications.
  
  
  RESULTS
  Review of the current literature strongly suggests a relationship between delayed acquisition of Th1 function in the allergy-prone infant, not only as a predictive marker of susceptibility to the development of allergic disease but also as an explanation for the unique vulnerability of these infants to viral infection, eg, bronchiolitis. Furthermore, viral infection during early development in the allergy-prone infant appears to facilitate allergic sensitization in early infancy. This interesting triad of immune deficiency, viral infection, and atopic genetic susceptibility may provide a basis for early detection of allergic disease and may offer new intervention strategies for the prevention of allergic and infectious disease in the young infant.
authors.affiliation: Department of Pediatrics and the International Center for Interdisciplinary Studies of Immunology, Georgetown University Medical Center, Washington, DC 20057, USA. bellantj@georgetown.edu
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Bellanti
authors.forename: Jonathan
authors.initials: J
authors.lastname: Malka-Rais
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Castro
authors.forename: Julia Mendez
authors.initials: JM
authors.lastname: de Inocencio
authors.forename: Aderbal
authors.initials: A
authors.lastname: Sabra
mesh_terms: D000486:Allergy and Immunology; D004198:Disease Susceptibility / Q000453:epidemiology / Q000276:immunology; D005314:Embryonic and Fetal Development / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000276:immunology; D007107:Immune System / Q000254:growth & development* / Q000276:immunology; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D015995:Prevalence; D012307:Risk Factors