APPLE ALLERGY - THE IGE-BINDING POTENCY OF APPLE STRAINS IS RELATED TO THE OCCURRENCE OF THE 18-KDA ALLERGEN

Low-temperature, acetone powder extracts were prepared from mature fru it of 16 apple strains. SDS-PAGE and immunoblot analysis revealed grea t variation in the relative amounts of the 18-kDa apple allergen in th ese extracts. EAST (RAST) scores, measured with individual and pool se ra from patients allergic to birch pollen and apples, ranged from 0.2 to 4.0 and were related to the relative amount of the 18-kDa protein. These findings were confirmed by ELISA-inhibition assays, dose-related histamine release, semiquantitative evaluation of immunoblots by abso rption/reflection densitometry, and skin prick tests with extracts of Golden Delicious, Boskoop, and Jamba apples (corresponding to a high, low, and very low 18-kDa allergen content). Additional open oral chall enge tests were performed with two apple-allergic patients and 15 and 16 apple strains. With all methods, the deduced allergenic potency dec reased in the following order: Golden Delicious > Boskoop > Jamba. The refore, we concluded that the IgE-binding potency of apple strains dep ends on the occurrence of the 18-kDa allergen.