Relationship between numbers of birch pollen and different particle sizes of the pollen antigens (Bet v) in the air in Stockholm, Sweden

Abstract

ABSTRACT Micronic antigens penetrate to the lower respiratory tract and cause serious lung problems. The existence of micronic antigens in pollinosis-caused pollen has been reported. We examined the appearance and the relationship of micronic particles of birch pollen antigens and birch pollen grains. Airborne particles were collected with a tandem filter system sampler composed of a 5 μm pore filter and a 0.3 μm pore Millipore filter in springtime at the Stockholm University campus in Stockholm. A fairly good correlation was observed between numbers of birch pollen and the amount of birch pollen antigens above 5 μm in diameter. In contrast, a good correlation was not observed between the amount of birch pollen antigens collected in 5 μm pore filters and the amount of the antigens passing through 5 μm pore filters and collected on Millipore filters. The appearance of a maximum value of birch pollen antigens collected on Millipore filters seemed to be delayed a few days after a maximum values had been obtained for birch pollen on a Burkard sampler or birch pollen antigens on 5 μm pore filters. Almost all birch pollen antigens were found during the birch pollen season and recognizable amounts of birch pollen antigens were not detectable after the birch pollen season. Most of the birch pollen antigens collected on 5 μm pore filters originated from birch pollen grains. In contrast, the antigens passing through 5 μm pore filters and collected on Millipore filters did not originate from pollen grains themselves, but were micronic particles, and appeared a few days after maximum values of birch pollen had been obtained.