title: Allergy or tolerance in children sensitized to peanut: prevalence and differentiation using component-resolved diagnostics.
abstract: BACKGROUND
  Not all peanut-sensitized children develop allergic reactions on exposure.
  
  
  OBJECTIVE
  To establish by oral food challenge the proportion of children with clinical peanut allergy among those considered peanut-sensitized by using skin prick tests and/or IgE measurement, and to investigate whether component-resolved diagnostics using microarray could differentiate peanut allergy from tolerance.
  
  
  METHODS
  Within a population-based birth cohort, we ascertained peanut sensitization by skin tests and IgE measurement at age 8 years. Among sensitized children, we determined peanut allergy versus tolerance by oral food challenges. We used open challenge among children consuming peanuts (n = 45); others underwent double-blind placebo-controlled challenge (n = 34). We compared sensitization profiles between children with peanut allergy and peanut-tolerant children by using a microarray with 12 pure components (major peanut and potentially cross-reactive components, including grass allergens).
  
  
  RESULTS
  Of 933 children, 110 (11.8%) were peanut-sensitized. Nineteen were not challenged (17 no consent). Twelve with a convincing history of reactions on exposure, IgE > or =15 kUa/L and/or skin test > or =8mm were considered allergic without challenge. Of the remaining 79 children who underwent challenge, 7 had > or =2 objective signs and were designated as having peanut allergy. We estimated the prevalence of clinical peanut allergy among sensitized subjects as 22.4% (95% CI, 14.8% to 32.3%). By using component-resolved diagnostics, we detected marked differences in the pattern of component recognition between children with peanut allergy (n = 29; group enriched with 12 children with allergy) and peanut-tolerant children (n = 52). The peanut component Ara h 2 was the most important predictor of clinical allergy.
  
  
  CONCLUSIONS
  The majority of children considered peanut-sensitized on the basis of standard tests do not have peanut allergy. Component-resolved diagnostics may facilitate the diagnosis of peanut allergy.
authors.affiliation: School of Translational Medicine, University of Manchester, NIHR Translational Research Facility in Respiratory Medicine, University Hospital of South Manchester NHS Foundation Trust, Manchester M23 9LT, United Kingdom.
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Nicolaou
authors.forename: Maryam
authors.initials: M
authors.lastname: Poorafshar
authors.forename: Clare
authors.initials: C
authors.lastname: Murray
authors.forename: Angela
authors.initials: A
authors.lastname: Simpson
authors.forename: Henric
authors.initials: H
authors.lastname: Winell
authors.forename: Gina
authors.initials: G
authors.lastname: Kerry
authors.forename: Annika
authors.initials: A
authors.lastname: Härlin
authors.forename: Ashley
authors.initials: A
authors.lastname: Woodcock
authors.forename: Staffan
authors.initials: S
authors.lastname: Ahlstedt
authors.forename: Adnan
authors.initials: A
authors.lastname: Custovic
mesh_terms: D010367:Arachis / Q000009:adverse effects / Q000276:immunology*; D002648:Child; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology; D015995:Prevalence; D012882:Skin Tests
chemical_list: D007073:Immunoglobulin E