title: Identifying infants at high risk of peanut allergy: the Learning Early About Peanut Allergy (LEAP) screening study.
abstract: BACKGROUND
  Peanut allergy (PA) is rare in countries in which peanuts are introduced early into infants' diets. Learning Early About Peanut Allergy (LEAP) is an interventional study aiming to assess whether PA can be prevented by oral tolerance induction.
  
  
  OBJECTIVE
  We sought to characterize a population screened for the risk of PA.
  
  
  METHODS
  Subjects screened for the LEAP interventional trial comprise the LEAP screening study cohort. Infants were aged 4 to 10 months and passed a prescreening questionnaire.
  
  
  RESULTS
  This analysis includes 834 infants (mean age, 7.8 months). They were split into the following: group I, patients with mild eczema and no egg allergy (n = 118); group II, patients with severe eczema, egg allergy, or both but 0-mm peanut skin prick test (SPT) wheal responses (n = 542); group III, patients with severe eczema, egg allergy, or both and 1- to 4-mm peanut wheal responses (n = 98); and group IV, patients with greater than 4-mm peanut wheal responses (n = 76). Unexpectedly, many (17%) in group II had peanut-specific IgE sensitization (≥ 0.35 kU/L); 56% of group III were similarly sensitized. In contrast, none of the patients in group I and 91% of those in group IV had peanut-specific IgE sensitization. Sensitization on skin testing to peanut (SPT response of 1-4 mm vs 0 mm) was associated with egg allergy and severe eczema (odds ratio [OR], 2.31 [95% CI, 1.39-3.86] and 2.47 [95% CI, 1.14-5.34], respectively). Similar associations were observed with specific IgE sensitization. Black race was associated with a significantly higher risk of peanut-specific IgE sensitization (OR, 5.30 [95% CI, 2.85-9.86]). Paradoxically, for a given specific IgE level, black race was protective against cutaneous sensitization (OR, 0.15 [95% CI, 0.04-0.61]).
  
  
  CONCLUSIONS
  Egg allergy, severe eczema, or both appear to be useful criteria for identifying high-risk infants with an intermediate level of peanut sensitization for entry into a PA prevention study. The relationship between specific IgE level and SPT sensitization needs to be considered within the context of race.
authors.affiliation: King's College London, King's Health Partners, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, and Department of Paediatric Allergy, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Du Toit
authors.forename: Graham
authors.initials: G
authors.lastname: Roberts
authors.forename: Peter H
authors.initials: PH
authors.lastname: Sayre
authors.forename: Marshall
authors.initials: M
authors.lastname: Plaut
authors.forename: Henry T
authors.initials: HT
authors.lastname: Bahnson
authors.forename: Herman
authors.initials: H
authors.lastname: Mitchell
authors.forename: Suzana
authors.initials: S
authors.lastname: Radulovic
authors.forename: Susan
authors.initials: S
authors.lastname: Chan
authors.forename: Adam
authors.initials: A
authors.lastname: Fox
authors.forename: Victor
authors.initials: V
authors.lastname: Turcanu
authors.forename: Gideon
authors.initials: G
authors.lastname: Lack
mesh_terms: D000485:Allergens / Q000276:immunology; D010367:Arachis / Q000276:immunology; D004485:Eczema / Q000150:complications; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007223:Infant; D008297:Male; D021183:Peanut Hypersensitivity / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D011379:Prognosis; D012306:Risk; D012882:Skin Tests
chemical_list: D000485:Allergens; D007073:Immunoglobulin E