Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

J Allergy Clin Immunol. 2004 Dec;114(6):1410-7. doi: 10.1016/j.jaci.2004.09.014.


Background: We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy.

Objective: We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1-homologous peanut allergen Ara h 8.

Methods: Recombinant Ara h 8 was cloned with degenerated primers and expressed in Escherichia coli. Nine Swiss and 11 Dutch patients with peanut and birch pollen allergy and a positive double-blind, placebo-controlled food challenge result to peanut were investigated for IgE reactivity to birch pollen and purified peanut allergens and cross-reactivity between birch and peanut. Ara h 8 stability against digestion and roasting was assessed by means of RAST inhibition. The IgE cross-linking potency of Ara h 8 was tested on the basis of basophil histamine release.

Results: During double-blind, placebo-controlled food challenge, all patients experienced symptoms in the oral cavity, progressing to more severe symptoms in 40% of patients. CAP-FEIA detected recombinant (r) Ara h 8-specific IgE in 85%. IgE binding to Ara h 8 was inhibited by Bet v 1 in peanut extract immunoblotting and in RAST inhibition. In EAST inhibition recombinant rAra h 8 inhibited IgE binding to peanut in 4 of 7 tested patient sera. Antipeanut response was dominated by Ara h 8 in 12 of 17 tested patients. Furthermore, our results demonstrate a low stability of Ara h 8 to roasting and no stability to gastric digestion. Basophil histamine release with rAra h 8 was more than 20% in 5 of 7 tested sera.

Conclusions: Peanut allergy might be mediated in a subgroup of our patients by means of cross-reaction of Bet v 1 with the homologous peanut allergen Ara h 8.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Allergens / immunology*
  • Amino Acid Sequence
  • Basophils / metabolism
  • Betula / immunology*
  • Cross Reactions
  • Double-Blind Method
  • Female
  • Histamine Release
  • Humans
  • Immunoglobulin E / immunology
  • Male
  • Molecular Sequence Data
  • Peanut Hypersensitivity / etiology*
  • Pepsin A / pharmacology
  • Pollen / immunology*
  • Recombinant Proteins / immunology


  • Allergens
  • Recombinant Proteins
  • Immunoglobulin E
  • Pepsin A