title: Measurement of Ara h 1-, 2-, and 3-specific IgE antibodies is useful in diagnosis of peanut allergy in Japanese children.
abstract: BACKGROUND
  Food challenges are time-consuming, expensive, and not always possible to perform. Therefore, new tools to diagnose food allergy are desired. The aim was to evaluate IgE antibodies to peanut allergens in the diagnosis of peanut allergy in Japanese children using ImmunoCAP(®) and IgE immunoblotting.
  
  
  METHODS
  The study included 2-13-yr-old consecutive patients (n = 57) referred to our specialist clinic for investigation of current peanut allergy using food challenge. All children had a previous doctor's diagnosis of peanut allergy and were on elimination diet. Serum samples were analyzed for IgE reactivity to peanut, recombinant (r) Ara h 1, 2, 3, 5, 8, and 9. IgE immunoblotting (n = 23) was performed using extracts from raw and roasted peanut.
  
  
  RESULTS
  Twenty-six of the children failed (allergic group), and 31 passed the peanut challenge (tolerant group). The rAra h 2 ImmunoCAP test was superior in its ability to differentiate between children in the allergic and tolerant groups with a sensitivity and specificity of 88% and 84%, respectively (cutoff, 0.35 kU(A)/l). The combination of rAra h 1, 2, and 3 resulted in a higher specificity (94%) when IgE to all of them was the criteria for positivity. ImmunoCAP generally showed a good agreement with immunoblotting using both raw and roasted peanut for IgE reactivity to Ara h 1, 2, and 3.
  
  
  CONCLUSIONS
  Measurement of IgE antibodies to rAra h 1, 2, and 3 is useful in the diagnosis of peanut allergy and in the investigation of reactions to raw and roasted peanut.
authors: Department of Allergy, Clinical Research Center for Allergology and Rheumatology, Sagamihara National Hospital, Sagamihara, Kanagawa, Japan. m-ebisawa@sagamihara-hosp.gr.jp
authors: Motohiro
authors: M
authors: Ebisawa
authors: Robert
authors: R
authors: Movérare
authors: Sakura
authors: S
authors: Sato
authors: Nobuyuki
authors: N
authors: Maruyama
authors: Magnus P
authors: MP
authors: Borres
authors: Takatsugu
authors: T
authors: Komata
mesh_terms: D055516:2S Albumins, Plant / Q000276:immunology*; D000293:Adolescent; D052179:Antigens, Plant / Q000276:immunology*; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007073:Immunoglobulin E / Q000097:blood* / Q000276:immunology; D008297:Male; D008565:Membrane Proteins; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology*; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; C500890:Ara h 2 allergen, Arachis hypogaea; C549941:Ara h 3 allergen, Arachis hypogea; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E