Simultaneous exposure of several allergens has an additive effect on multisensitized basophils

Background: Patients immunoglobulin (Ig)E‐sensitized to more than one allergen in their environment often have more symptoms than mono‐sensitized individuals, which indicates that the allergens may have an additive effect. In order to study if such an effect could be detected on the inflammatory, cellular level, multisensitized basophils were challenged with various dose combinations of two relevant allergens. Methods: Basophils from patients IgE‐sensitized to timothy/cat, birch/cat, timothy/mite and cat/mite were challenged with serial dilutions of different combinations of the two allergens. The basophil response was measured as CD63 expression analysed by flow cytometry. Results: The doses of each allergen in the pair had an additive effect resulting in a shift of the dose–response curve to higher CD63 percentages and higher CD‐sens. Conclusions: If a patient has IgE antibodies and thus sensitized basophils to more than one allergen, to which he is simultaneously exposed, the additive effect should be considered. Even low concentrations of IgE antibodies could be of clinical relevance in such a situation.