title: Tear and conjunctival changes during the allergen-induced early- and late-phase responses.
abstract: BACKGROUND
  Allergic eye disease is common, but little is known about the underlying disease mechanisms. Conjunctival allergen challenge causes symptoms similar to those of seasonal allergic conjunctivitis and is a useful model to study.
  
  
  OBJECTIVE
  We have used allergen challenge to investigate the course of the ocular response, tear inflammatory mediators, tissue adhesion protein expression, and cellular infiltration.
  
  
  METHODS
  Eighteen atopic patients and 4 nonatopic control subjects were challenged with extracted mixed grass or Dermatophagoides pteronyssinus in one eye and control vehicle in the other. The clinical response was recorded, and tears were collected over a 6-hour period. Conjunctival biopsy specimens were taken from the challenged eye at 6 or 24 hours.
  
  
  RESULTS
  An early-phase response (maximal at 20 minutes) showed a significant increase in tear histamine and tryptase levels, reducing to control levels again by 40 minutes. At 6 hours, a late-phase response occurred with increased symptoms, a second peak of tear histamine and eosinophil cationic protein but not tryptase, upregulation of the adhesion molecules E-selectin and intercellular adhesion molecule, and a cellular infiltrate of mast cells, neutrophils, eosinophils, macrophages, and basophils, with T cells increased only in bulbar biopsy specimens.
  
  
  CONCLUSIONS
  The early peaks of tear histamine plus tryptase indicate that the mast cell is responsible for the early-phase response, but basophils may be involved in the late-phase response. Both tear and biopsy findings underline the significance of the late-phase response as the transition between a type I response and clinical disease.
authors.affiliation: Southampton Eye Unit and Allergy and Inflammation Sciences, Southampton General Hospital, Southampton, UK.
authors.forename: A S
authors.initials: AS
authors.lastname: Bacon
authors.forename: P
authors.initials: P
authors.lastname: Ahluwalia
authors.forename: A M
authors.initials: AM
authors.lastname: Irani
authors.forename: L B
authors.initials: LB
authors.lastname: Schwartz
authors.forename: S T
authors.initials: ST
authors.lastname: Holgate
authors.forename: M K
authors.initials: MK
authors.lastname: Church
authors.forename: J I
authors.initials: JI
authors.lastname: McGill
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology; D000818:Animals; D039741:Antigens, Dermatophagoides; D002415:Cats; D003233:Conjunctivitis, Allergic / Q000276:immunology* / Q000503:physiopathology; D004285:Dogs; D019040:E-Selectin / Q000096:biosynthesis; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007962:Leukocytes / Q000166:cytology / Q000276:immunology; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D008407:Mast Cells / Q000166:cytology / Q000276:immunology; D008875:Middle Aged; D008925:Mites / Q000276:immunology; D006109:Poaceae / Q000276:immunology; D013666:Tears / Q000276:immunology* / Q000378:metabolism; D013997:Time Factors; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D019040:E-Selectin; D006023:Glycoproteins; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1