Specific IgE to individual allergen components: Peanut

The measurement of IgE to peanut extract has been incorporated into the diagnosis of peanut allergy since the 1970s. After Western-blotting provided insight in the relevance of specific allergens present in crude peanut extract, the role of individual allergenic protein became clear. Despite the identification of 17 different peanut allergen components, research has focused on the roles of Ara h 1, 2, 3, 6, 8, and 9. Not only in peanut allergies as such, but also during allergen immunotherapy it was shown that IgE to Ara h 2 and 6 had a high predictive value for clinically relevant peanut allergy.