title: Egg-white-specific IgA and IgA2 antibodies in egg-allergic children: is there a role in tolerance induction?
abstract: BACKGROUND
  Decreased serum food-specific IgA antibodies have been associated with allergic disease in cross-sectional, case-control studies. The purpose of this study was to prospectively compare egg-white-(EW)-specific IgA and IgA2 levels between egg-allergic children and children tolerating egg.
  
  
  METHODS
  Seventeen egg-allergic children were followed prospectively. Total IgA, EW-specific IgA, and EW-specific IgA2 levels were measured in their sera with a sensitive ELISA. As negative controls were used children with no previous history of egg allergy. Egg-allergic children with or without concomitant milk allergy were evaluated as additional controls with measurement of casein-specific IgA.
  
  
  RESULTS
  After 2.5 ± 0.9 yrs, nine out of the 17 allergic children became tolerant and eight remained allergic to baked egg. Baseline EW-specific IgA2 levels were significantly lower in the egg-allergic subjects (median 23.9 ng/ml) compared with the negative control subjects (99.4 ng/ml) and increased significantly by 28% over the study time period in eight out of the nine allergic children that became tolerant to baked egg. There was no significant change over time in EW-specific IgA in any of the study groups. Non-milk-allergic subjects with concomitant egg allergy had almost threefold higher casein-specific IgA levels than the milk- and egg-allergic subjects (p = 0.025).
  
  
  CONCLUSIONS
  These results suggest a potential role for allergen-specific IgA2 antibodies in the induction of food tolerance. Furthermore, they support the hypothesis that immature or impaired production of allergen-specific IgA2 may be associated with the pathophysiology of food allergy, a defect that seems to be selective for the culprit allergen.
authors.affiliation: Division of Allergy & Immunology, The Jaffe Food Allergy Research Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Allergy and Clinical Immunology, 424 General Military Training Hospital, Thessaloniki, Greece.
authors.forename: George N
authors.initials: GN
authors.lastname: Konstantinou
authors.forename: Anna
authors.initials: A
authors.lastname: Nowak-Węgrzyn
authors.forename: Ramon
authors.initials: R
authors.lastname: Bencharitiwong
authors.forename: Luda
authors.initials: L
authors.lastname: Bardina
authors.forename: Scott H
authors.initials: SH
authors.lastname: Sicherer
authors.forename: Hugh A
authors.initials: HA
authors.lastname: Sampson
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D002364:Caseins / Q000276:immunology; D002417:Cattle; D002675:Child, Preschool; D021181:Egg Hypersensitivity / Q000150:complications / Q000276:immunology*; D015387:Egg Proteins, Dietary / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007108:Immune Tolerance; D056724:Immunity, Humoral; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology; D007223:Infant; D008297:Male; D016269:Milk Hypersensitivity / Q000150:complications / Q000276:immunology*; D011446:Prospective Studies
chemical_list: D000485:Allergens; D002364:Caseins; D015387:Egg Proteins, Dietary; D007070:Immunoglobulin A
keywords: egg white; food allergy; immunoglobulin A; neutralizing antibodies; tolerance induction