Semiquantitative and qualitative analysis of pre‐seasonal airborne birch pollen allergens in different particle sizes

Bet v 1, the major allergen of birch pollen, has been reported to be synthetized in pollen grains shortly before anthesis. In order to obtain a better understanding of the causative agents of allergic symptoms which appear before the actual pollen season, the activity birch pollen antigen in outdoor air have been studied, using polyclonal antibodies against birch pollen, and monoclonal antibodies against Bet v 1. Using a size‐selective bioaerosol sampler (SSBAS), birch pollen antigen concentrations were analysed separately in different particle size classes, down to the molecular size range. About a week before the anthesis of alder, antigens were already detected in outdoor air samples. They were found mainly in the smallest particle size classes and might have had their origin in the developing leaves and flower structures of Betulaceae trees. At the beginning of birch anthesis Bet v 1 activity in the air increased markedly. The smallest particles may have been orbicules (2–4 μm) and starch granules (0....