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

Abstract

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.

• Authors: Diana Mittag, Jaap Akkerdaas, Barbara K Ballmer-Weber, Lothar Vogel, Marjolein Wensing, Wolf-Meinhard Becker, Stef J Koppelman, André C Knulst, Arthur Helbling, Susan L Hefle, Ronald Van Ree, Stefan Vieths
• Journal: The Journal of allergy and clinical immunology (J Allergy Clin Immunol) Vol. 114 Issue 6 Pg. 1410-7 (Dec 2004) ISSN: 0091-6749 [Print] United States
• PMID: 15577846 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Allergens
• Recombinant Proteins
• Immunoglobulin E
• Pepsin A

Topics

• 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)