title: Peanut allergy: Clinical and immunologic differences among patients from 3 different geographic regions.
abstract: BACKGROUND
  Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens.
  
  
  OBJECTIVE
  We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach.
  
  
  METHODS
  Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed.
  
  
  RESULTS
  American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age.
  
  
  CONCLUSIONS
  Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.
authors.affiliation: Department of Pediatric Allergy, Mount Sinai School of Medicine, New York, NY, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Vereda
authors.forename: Marianne
authors.initials: M
authors.lastname: van Hage
authors.forename: Staffan
authors.initials: S
authors.lastname: Ahlstedt
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Ibañez
authors.forename: Javier
authors.initials: J
authors.lastname: Cuesta-Herranz
authors.forename: Jenny
authors.initials: J
authors.lastname: van Odijk
authors.forename: Magnus
authors.initials: M
authors.lastname: Wickman
authors.forename: Hugh A
authors.initials: HA
authors.lastname: Sampson
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D021183:Peanut Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology*; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D014481:United States / Q000453:epidemiology