Health Impacts of airborne Allergen Information Network

Summary of the results of the EU-project HIALINE

Exposure to allergens is one of several factors determining sensitization and allergic symptoms in individuals. Exposure to aeroallergens from pollen is assessed by counting allergenic pollen in ambient air. However, proof is lacking that pollen count is representative for allergen exposure. We therefore monitored simultaneously birch, grass and olive pollen counts and their corresponding major pollen allergens Bet v 1, Phl p 5 and Ole e 1 across Europe. Here we report some of our findings.

Birch pollen

The major allergens from the top 3 airborne allergens in Europe (grasses, birch and olive) were sampled with a cascade impactor, extracted and analyzed by allergen specific ELISAs. Pollen counts were measured by standard pollen traps and correlated with the weather data. Atmospheric dynamic modeling was done with the System for Integrated modeLling of Atmospheric coMposition (SILAM), to analyse where the sampled pollen and allergens originated.

At all locations in Europe we found that the allergens correlated closely with pollen counts, showing that pollen is the main if not sole origin of allergens. However, at every location days were found with pollen that released much more allergen (higher pollen potency) than on other days. These were not single events, as comparing the 10% highest potency pollen with the 10% lowest potency pollen for one location, differences of 12-fold (olive pollen) were measured. In general, 10-fold potency differences for every pollen species were common.

When comparing locations, grass pollen showed the largest variability across Europe with France having the highest yearly average grass pollen potency, 7-fold higher than Portugal. For birch pollen the yearly allergen release capacity per pollen was comparable between locations, but still varied more than 2-fold.

Already olive pollen from two locations 400 km apart varied 4-fold in their average allergen release potency. In Portugal, we could model occasions where pollen from Spain with much higher allergen release potency was responsible for allergen exposure.

We think a combined effort of allergen measurements, pollen counts and dynamic atmospheric modeling is needed to assess aeroallergen exposure. Pollen counts, which already vary greatly across Europe, only represent part of the exposure picture. Differences in pollen potency and atmospheric transport are on top of the pollen count variations.

Of course more studies on the effects of climate change on pollen counts and potency are needed. With 3 years the project was too short to reliably calculate these factors. In addition, patient symptoms need to be evaluated simultaneously.

With HIALINE we successfully established an aeroallergen-measuring network using standardized methods across Europe. We could show that aeroallergen exposure not only depends on pollen but also on the amount of allergen these pollen carry, and that this varies >10-fold between days, locations, and years. Atmospheric transport of high potency pollen to locations that normally have a lower allergen exposure was demonstrated.

The Project is coordinated by Prof. Dr. J. Buters, ZAUM-Center for Allergy and Environment, with 13 partners in 11 countries for 3 years with a volume of about € 700.000. The work-package leaders are Lorenzo Cecchi (Italy), Auli Rantio-Lehtimäki (Finland), Mikhail Sofiev (Finland) and Gerald Reese (Germany).

Acknowledgement:

The research leading to these results has received funding from the European Union, in the framework of the Health Programme.

Read more about HIALINE:

1. www.HIALINE.eu

2. Jeroen T.M. Buters, Michel Thibaudon, Matt Smith, Roy Kennedy, Auli Rantio-Lehtimäki, Roberto Albertini, Gerald Reese, Bernhard Weber, Carmen Galan, Rui Brandao, Celia Antunes, Siegfried Jäger, Uwe Berger, Sevcan Celenk, Łukasz Grewling1, Bogdan Jackowiak, Ingrida Sauliene, Ingrid Weichenmeier, Gudrun Pusch, Marje Prank, Mikhial Sofiev,and Lorenzo Cecchi. Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study. Atmos Environ 2012, in press.

3. Buters JTM, Weichenmeier I, Ochs S, Pusch G, Kreyling W, Boere AJ, Schober W, Behrendt H. The allergen Bet v 1 in fractions of ambient air deviates from birch pollen counts. Allergy 2010;65:850-858.