title: Asthma: an epidemic of dysregulated immunity.
abstract: The remarkable increase in asthma prevalence that has occurred over the last two decades is thought to be caused by changes in the environment due to improved hygiene and fewer childhood infections. However, the specific infections that limit T helper type 2 (T(H)2)-biased inflammation and asthma are not fully known. Infectious organisms, including commensal bacteria in the gastrointestinal tract and hepatitis A virus, may normally induce the development of regulatory T (T(R)) cells and protective immunity that limit airway inflammation and promote tolerance to respiratory allergens. In the absence of such infections, T(H)2 cells--which are developmentally related to T(R) cells--develop instead and coordinate the development of asthmatic inflammation.
authors.affiliation: Division of Immunology and Allergy, Department of Pediatrics, Stanford University, Stanford, CA 94305-5208, USA. umetsu@stanford.edu
authors.forename: Dale T
authors.initials: DT
authors.lastname: Umetsu
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: McIntire
authors.forename: Omid
authors.initials: O
authors.lastname: Akbari
authors.forename: Claudia
authors.initials: C
authors.lastname: Macaubas
authors.forename: Rosemarie H
authors.initials: RH
authors.lastname: DeKruyff
mesh_terms: D015703:Antigens, CD; D001249:Asthma / Q000453:epidemiology / Q000276:immunology* / Q000473:pathology; D003141:Communicable Diseases / Q000276:immunology; D020022:Genetic Predisposition to Disease; D006801:Humans; D006920:Hygiene; D007108:Immune Tolerance / Q000276:immunology; D060945:Inducible T-Cell Co-Stimulator Ligand; D015995:Prevalence; D011506:Proteins / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology / Q000382:microbiology / Q000821:virology; D014481:United States / Q000453:epidemiology
chemical_list: D015703:Antigens, CD; C498514:ICOSLG protein, human; D060945:Inducible T-Cell Co-Stimulator Ligand; D011506:Proteins