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Ernährung und Allergie

Internet Symposium on Food Allergens 2(2): 87-123 (2000) http://www.food-allergens.de

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Allergen Data Collection:
Peanut (Arachis hypogaea)
Authors in alphabetical order [contact information]
Gary A.
Sue L.
Jonathan O'B
Scott H.
BANNON (Little Rock, AR, USA)
BESLER (Hamburg, Germany)
HEFLE (Lincoln, NE, USA)


Among food allergy, peanut allergy is common and severe. Epidemiologic studies of the general population  estimate a prevalence rate of 0.5%, and peanut allergy accounts for 10-47% of food- induced anaphylactic reactions. Symptoms may vary in severity from mild urticaria or localized oral symptoms, to severe systemic reactions that can be fatal. Reactions typically occur within a few minutes following ingestion. Peanut hypersensitivity usually begins in early childhood and usually persists throughout life, with only a small percentage of young children achieving tolerance.

Diagnosis rests upon a clear history of severe reaction with laboratory evidence of peanut-specific IgE antibody. Reactions could be confirmed by oral challenge procedures, when anaphylactic reactions are not expected.  Diagnostic skin prick tests and determination of specific IgE are sensitive and have an excellent negative predictive value. Since very small amounts of peanut protein can elicit an allergic response, and the food is ubiquitous in most food supplies, accidental ingestion with reaction is common. Hidden peanut proteins have been reported as causes of adverse reactions to confectionary products, pastry, and Asian food. While crude peanut oil can induce allergic reactions, the allergenicity of refined peanut oils is controversial. Although peanut shares cross-reacting proteins with other legumes (e.g. - soybean, pea), clinical cross reactivity is not common, except for possibly lupine. Allergy to peanut most commonly occurs in atopic individuals who may have other food allergies (e.g. - egg, tree nut), but there are no known clinically relevant cross reacting proteins with tree nuts (e.g. - walnut). Peanuts and its products should always be declared according to a list of the Codex Alimentarius Commission on mandatory labelling of prepackaged foods. Although there are some promising advances in immunotherapy of peanut allergy, the only currently available treatment consists of strict avoidance with immediate availability of epinephrine for self-injection in the event of an accidental ingestion.

Three major peanut allergens are recognized by more than 50% of peanut allergic individuals: Ara h 1 (vicilin), Ara h 2 (conglutin- homologue protein), and Ara h 3 / Ara h 4 (glycinin). These allergens are seed storage proteins and their primary structure and major IgE-binding epitopes have been characterized. More recently three additional minor allergens Ara h 6 and Ara h 7 (both conglutin- homologue proteins) as well as the plant pan- allergen profilin (Ara h 5) were described.
The present review summarizes data on prevalence, symptoms, diagnostic features, immunotherapy, allergen stability, and allergen sources as well as molecular biological and allergenic properties of the major peanut allergens in tabular form.
1 Prevalence of Peanut Allergy
2 Outgrowing / Persistence of Peanut Allergy
3 Symptoms of Peanut Allergy
4 Diagnostic Features of Peanut Allergy
5 Therapy of Peanut Allergy
6 Composition of Peanut
7 Allergens of Peanut
7.1 Sensitization to Peanut Allergens
7.2 Properties of Vicilin (Ara h 1)
7.3 Properties of Conglutin-like Protein (Ara h 2)
7.4 Properties of Glycinin (Ara h 3 / Ara h 4)
7.5 Properties of Profilin (Ara h 5)
7.6 Properties of Conglutin-homologous Protein (Ara h 6)
7.7 Properties of Conglutin-homologous Protein (Ara h 7)
8 Isolation & Preparation
9 Cross-Reactivities
10 Stability of Peanut Allergens
11 Allergen Sources
12 Food Allergen Labelling
13 References

The reference lists of the Allergen Data Collections are based mainly on searches of Medline and FSTA (Food Science & Technology Abstracts) databases up to the related dates of publication. The scientific rigor of the studies listed is variable and not subject of critique or evaluation by the authors or the editor of the Allergen Data Collections. The reader should be aware of considerable problems in comparing data from different studies (eg. patient cohorts, diagnostic performances, possible flaws in allergen preparations and methodologies for allergen characterization) and is encouraged to review the original publications.
The information provided by the Internet Symposium on Food Allergens is for educational, communication and information purposes only and is not intended to replace or constitute medical advice or treatments. Neither the authors nor the editorial board of the Internet Symposium on Food Allergens is responsible for use which might be made of the information.

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