title: Utility of specific IgE to Ara h 6 in peanut allergy diagnosis.
abstract: BACKGROUND
  Specific IgE to Ara h 2 has been shown to be useful in the diagnosis of peanut allergy, whereas the peanut lipid transfer protein, Ara h 9, has been suggested to be responsible for peanut allergy in the Mediterranean population.
  
  
  OBJECTIVE
  To better characterize peanut allergy in children from a Mediterranean area and determine the value of specific IgE to Ara h 6 (conglutinin, 2S albumin) for the diagnosis of peanut allergy.
  
  
  METHODS
  Ninety-one children with suspected allergy to edible vegetables were included in the study. They were classified as allergic or tolerant to peanut. Specific IgE to peanut allergens was measured by a commercially available microarray (ImmunoCAP ISAC 112, ThermoFisher, Uppsala, Sweden).
  
  
  RESULTS
  Patients allergic to peanut showed positive specific IgE changes to peanut seed storage proteins (Ara h 1, Ara h 2, Ara h 3, and Ara h 6) more frequently than tolerant subjects. Ara h 9 showed a similar frequency of reactivity in the 2 groups. Ara h 6 was the allergen most frequently recognized by patients with allergy. Four patients with allergy were found to be mono-sensitized to Ara h 6. Ara h 2 and Ara h 6 showed similar diagnostic accuracy (areas under the curve 0.792 and 0.852). A combined cutoff point for Ara h 2 (≥0.1 ISU) and Ara h 6 (≥2 ISU) yielded the best diagnostic performance (sensitivity 0.77, specificity 0.97, positive predictive value 0.89, negative predictive value 0.93).
  
  
  CONCLUSIONS
  Peanut allergy cannot be ruled out without obtaining a negative determination of Ara h 6.
authors.affiliation: Department of Allergy, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain. Electronic address: maria.pedrosa@idipaz.es.
authors.forename: María
authors.initials: M
authors.lastname: Pedrosa
authors.affiliation: Department of Allergy, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Boyano-Martínez
authors.affiliation: Department of Allergy, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: García-Ara
authors.affiliation: Department of Allergy, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Caballero
authors.affiliation: Department of Allergy, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Quirce
mesh_terms: D055516:2S Albumins, Plant / Q000097:blood / Q000276:immunology*; D000485:Allergens / Q000097:blood / Q000276:immunology*; D052179:Antigens, Plant / Q000097:blood / Q000276:immunology*; D010367:Arachis / Q000737:chemistry / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006023:Glycoproteins / Q000097:blood / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008565:Membrane Proteins; D021183:Peanut Hypersensitivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D010940:Plant Proteins / Q000097:blood / Q000276:immunology; D011237:Predictive Value of Tests; D011446:Prospective Studies
chemical_list: D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; C500890:Ara h 2 allergen, Arachis hypogaea; C492737:Ara h 6 allergen, Arachis hypogaea; C544631:Ara h 9 allergen, peanut; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E