title: Delayed clinical and ex vivo response to mammalian meat in patients with IgE to galactose-alpha-1,3-galactose.
abstract: BACKGROUND
  In 2009, we reported a novel form of delayed anaphylaxis to red meat related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Although patients were remarkably consistent in their description of a 3- to 6-hour delay between eating mammalian meat and the appearance of symptoms, this delay has not been demonstrated under observed studies.
  
  
  OBJECTIVE
  We sought to formally document the time course of clinical symptoms after the ingestion of mammalian meat in subjects with IgE to alpha-gal and to monitor ex vivo for the appearance of markers of an allergic reaction.
  
  
  METHODS
  Open food challenges were performed with mammalian meat in 12 subjects with a history of severe urticarial reactions 3 to 6 hours after eating beef, pork, or lamb, as well as in 13 control subjects. Blood samples were taken hourly during each challenge.
  
  
  RESULTS
  Ten of 12 subjects with IgE to alpha-gal had clinical evidence of a reaction during the food challenge (vs none of the control subjects, P < .001). The reactions occurred 3 to 7 hours after the initial ingestion of mammalian meat and ranged from urticaria to anaphylaxis. Tryptase levels were positive in 3 challenges. Basophil activation, as measured by increased expression of CD63, correlated with the appearance of clinical symptoms.
  
  
  CONCLUSIONS
  The results presented provide clear evidence of an IgE-mediated food allergy that occurs several hours after ingestion of the inciting allergen. Moreover, here we report that in vivo basophil activation during a food challenge occurs in the same time frame as clinical symptoms and likely reflects the appearance of the antigen in the bloodstream.
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va. Electronic address: scottcommins@virginia.edu.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Commins
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Hayley R
authors.initials: HR
authors.lastname: James
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Whitney
authors.initials: W
authors.lastname: Stevens
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Shawna L
authors.initials: SL
authors.lastname: Pochan
authors.affiliation: Duke Asthma, Allergy and Airway Center, Duke University, Durham, NC.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Land
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Carol
authors.initials: C
authors.lastname: King
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Susan
authors.initials: S
authors.lastname: Mozzicato
authors.affiliation: Asthma and Allergic Diseases Center, Department of Medicine, University of Virginia, Charlottesville, Va.
authors.forename: Thomas A E
authors.initials: TA
authors.lastname: Platts-Mills
mesh_terms: D000328:Adult; D000707:Anaphylaxis / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D000818:Animals; D001491:Basophils / Q000276:immunology / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002417:Cattle; D004187:Disaccharides / Q000097:blood* / Q000276:immunology; D005260:Female; D005512:Food Hypersensitivity / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008460:Meat / Q000009:adverse effects*; D008875:Middle Aged; D012756:Sheep; D013552:Swine; D060149:Tetraspanin 30 / Q000276:immunology; D013997:Time Factors; D014581:Urticaria / Q000209:etiology / Q000276:immunology* / Q000473:pathology
chemical_list: D015415:Biomarkers; C554586:CD63 protein, human; D004187:Disaccharides; D060149:Tetraspanin 30; C055075:galactosyl-(1-3)galactose; D007073:Immunoglobulin E
keywords: Anaphylaxis; alpha-gal; basophil; food allergy; mammalian meat