title: Dehydrated egg white: an allergen source for improving efficacy and safety in the diagnosis and treatment for egg allergy.
abstract: BACKGROUND
  Raw and cooked eggs are used as allergens in oral food challenge (OFC). Raw egg is the best option, as it keeps proteins intact and retains their allergenicity, albeit microbiologically safe manipulation is difficult. Therefore, the use of dehydrated egg white (DEW) could improve the efficacy and safety profile of OFC. The aim of the study was to compare the allergenicity of DEW, a product that undergoes a double heat treatment (pasteurization and drying), with that of raw egg white (REW) and determine the efficacy of DEW in the diagnosis of egg allergy.
  
  
  METHODS
  We conducted a prospective study of 40 egg-allergic patients who visited our outpatient clinic. Each patient underwent OFC with DEW and REW to determine the correlation between the tests. DEW and REW extracts were analyzed using SDS-PAGE. We compared the allergenicity of both extracts using IgE immunoblotting with a serum pool from patients with positive OFC results.
  
  
  RESULTS
  Ten patients (25%) had positive OFC results with both DEW and REW, and the doses that triggered an allergic reaction in each patient were similar (p > 0.05). All 30 patients (75%) with a negative OFC result with DEW also had negative OFC results with REW. SDS-PAGE and IgE immunoblotting revealed that the protein composition and IgE-binding capacity of both extracts were virtually identical.
  
  
  CONCLUSIONS
  This is the first time that it is shown that the allergenicity of commercially available DEW is equivalent to raw egg whites. In vivo and in vitro tests showed that processing of DEW does not affect the allergenicity of egg proteins. DEW is an effective and microbiologically safer source of allergen for the diagnosis of egg allergy. Furthermore, DEW can be used in egg oral immunotherapy.
authors.affiliation: Allergy Department, Hospital Infantil Universitario Niño Jesús, Madrid, Spain.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Escudero
authors.forename: Silvia
authors.initials: S
authors.lastname: Sánchez-García
authors.forename: Pablo
authors.initials: P
authors.lastname: Rodríguez del Río
authors.forename: Carlos
authors.initials: C
authors.lastname: Pastor-Vargas
authors.forename: Cristina
authors.initials: C
authors.lastname: García-Fernández
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Pérez-Rangel
authors.forename: Antonio
authors.initials: A
authors.lastname: Ramírez-Jiménez
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Ibáñez
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003888:Desensitization, Immunologic / Q000379:methods* / Q000592:standards; D003890:Desiccation; D021181:Egg Hypersensitivity / Q000175:diagnosis* / Q000276:immunology / Q000628:therapy; D004529:Egg White; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008297:Male; D011446:Prospective Studies; D011485:Protein Binding; D015203:Reproducibility of Results
chemical_list: D000485:Allergens; D007073:Immunoglobulin E