Background Beech and oak pollen are potential allergen sources with a world-wide distribution.
Objective We aimed to characterize the allergen profile of beech and oak pollen and to study cross-reactivities with birch and grass pollen allergens.
Methods Sera from tree pollen-allergic patients with evidence for beech and oak pollen sensitization from Basel, Switzerland, (n=23) and sera from birch pollen-allergic patients from Vienna, Austria, (n=26) were compared in immunoblot experiments for IgE reactivity to birch (Betula pendula syn. verrucosa), beech (Fagus sylvatica) and oak (Quercus alba) pollen allergens. Subsequently, beech and oak pollen allergens were characterized by IgE inhibition experiments with purified recombinant and natural allergens and with allergen-specific antibody probes. Birch-, beech- and oak pollen-specific IgE levels were determined by ELISA.
Results Beech and oak pollen contain allergens that cross-react with the birch pollen allergens Bet v 1, Bet v 2 and Bet v 4 and with the berberine bridge enzyme-like allergen Phl p 4 from timothy grass pollen. Sera from Swiss and Austrian patients exhibited similar IgE reactivity profiles to birch, beech and oak pollen extracts. IgE levels to beech and oak pollen allergens were lower than those to birch pollen allergens.
Conclusion IgE reactivity to beech pollen is mainly due to cross-reactivity with birch pollen allergens, and a Phl p 4-like molecule represented another predominant IgE-reactive structure in oak pollen. The characterization of beech and oak pollen allergens and their cross-reactivity is important for the diagnosis and treatment of beech and oak pollen allergy.