14 research outputs found
Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study
Exposure to allergens is pivotal in determining sensitization and allergic symptoms in individuals. Pollen
grain counts in ambient air have traditionally been assessed to estimate airborne allergen exposure.
However, the exact allergen content of ambient air is unknown. We therefore monitored atmospheric
concentrations of birch pollen grains and the matched major birch pollen allergen Bet v 1 simultaneously
across Europe within the EU-funded project HIALINE (Health Impacts of Airborne Allergen Information
Network).
Pollen count was assessed with Hirst type pollen traps at 10 l min 1 at sites in France, United Kingdom,
Germany, Italy and Finland. Allergen concentrations in ambient air were sampled at 800 l min 1 with
a Chemvol high-volume cascade impactor equipped with stages PM > 10 mm, 10 mm > PM > 2.5 mm, and
in Germany also 2.5 mm > PM > 0.12 mm. The major birch pollen allergen Bet v 1 was determined with an
allergen specific ELISA. Bet v 1 isoform patterns were analyzed by 2D-SDS-PAGE blots and mass spectrometric
identification. Basophil activation was tested in an Fc 3R1-humanized rat basophil cell line
passively sensitized with serum of a birch pollen symptomatic patient.
Compared to 10 previous years, 2009 was a representative birch pollen season for all stations. About
90% of the allergen was found in the PM > 10 mm fraction at all stations. Bet v 1 isoforms pattern did not
vary substantially neither during ripening of pollen nor between different geographical locations. The
average European allergen release from birch pollen was 3.2 pg Bet v 1/pollen and did not vary much
between the European countries. However, in all countries a >10-fold difference in daily allergen release
per pollen was measured which could be explained by long-range transport of pollen with a deviating allergen release. Basophil activation by ambient air extracts correlated better with airborne allergen than
with pollen concentration.
Although Bet v 1 is a mixture of different isoforms, its fingerprint is constant across Europe. Bet v 1 was
also exclusively linked to pollen. Pollen from different days varied >10-fold in allergen release. Thus
exposure to allergen is inaccurately monitored by only monitoring birch pollen grains. Indeed,
a humanized basophil activation test correlated much better with allergen concentrations in ambient air
than with pollen count. Monitoring the allergens themselves together with pollen in ambient air might
be an improvement in allergen exposure assessmen
Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study
Seasonal variation of birch and grass pollen loads and allergen release at two sites in the German Alps
Less vegetated mountainous areas may provide better conditions for allergy sufferers. However, atmospheric transport can result in medically relevant pollen loads in such regions. The majority of investigations has focused on the pollen load, expressed as daily averages of pollen per cubic meter of air (pollen grains/m3); however, the severity of allergic symptoms is also determined by the actual allergen content of this pollen, its pollen potency, which may differ between high and low altitudes. We analysed airborne birch and grass pollen concentrations along with allergen content (birch: Bet v 1, grass: Phl p 5) at two different altitudes (734 and 2650 m a.s.l.) in the Zugspitze region (2009-2010). Back-trajectories were calculated for the high altitude site and for specific days with abrupt increases in pollen potency. We observed several days with medically relevant pollen concentrations at the highest site. In addition, a few days with pollen were not associated with allergens and vice versa. The calculated seasonal mean allergen release per pollen grain was 1.8-3.3 pg Bet v 1 and 5.7 pg Phl p 5 in the valley and 1.1-3.7 pg Bet v 1 and 0.7-1.5 pg Phl p 5 at the high altitude site. Back-trajectories revealed that high pollen potency at the higher site was generally associated with south-westerly to south-easterly (birch), or northerly (grass) wind directions. By investigating days with sudden increases in pollen potency, however, it was difficult to draw definitive conclusions on long- or short-range transport. Our findings suggest that people allergic to pollen might suffer less at higher altitudes and further indicate that a risk assessment relying on the actual concentration of airborne pollen does not necessarily reflect the actual allergy exposure of individuals