Induction of specific histamine release from basophils with purified natural and recombinant birch pollen allergens

As much as 15% of the population in industrialized countries suffers from type I allergic symptoms (rhinitis, conjunctivitis, and bronchial asthma). One approach toward this disease involves the production of recombinant allergens in Escherichia coli and their purification for diagnostic and therapeutic purposes. In this study we compared the IgE-binding capacity of natural and recombinant birth allergens with their functional ability to release histamine from allergic patients' basophils via cross-linking of high-affinity Fc epsilon-receptors. The recombinant as well as pollen-derived Bet v I and birch profilin (Bet v II) were purified and tested in parallel on IgE immunoblots and in in vitro histamine release tests (n = 21). We observed an excellent correlation between allergen-induced histamine release and birch pollen RAST (r = 0.881, p < 0.002). Nonspecific histamine release as a result of a cell toxic effect of the allergen preparations was never observed from basophils of donors without birch pollen allergy. The specificity of the presented effector model is also documented by the specific desensitization of patients' basophils with the recombinant allergens. These data may provide a basis for the use of purified recombinant allergens in sensitive and specific in vitro allergy tests monitoring the effector situation in allergic patients, which therefore may represent a possible alternative for in vivo diagnostic methods.