Pollen‐related allergy in Europe D'Amato, G.; Spieksma, F. Th. M.; Liccardi, G. ...
Allergy (Copenhagen),
June 1998, Letnik:
53, Številka:
6
Journal Article
Recenzirano
The increasing mobility of Europeans for business and leisure has led to a need for reliable information about exposure to seasonal airborne allergens during travel abroad. Over the last 10 years or ...so, aeropalynologic and allergologic studies have progressed to meet this need, and extensive international networks now provide regular pollen and hay‐fever forecasts. Europe is a geographically complex continent with a widely diverse climate and a wide spectrum of vegetation. Consequently, pollen calendars differ from one area to another; however, on the whole, pollination starts in spring and ends in autumn. Grass pollen is by far the most frequent cause of pollinosis in Europe. In northern Europe, pollen from species of the family Betulaceae is a major cause of the disorder. In contrast, the mild winters and dry summers of Mediterranean areas favor the production of pollen types that are rarely found in central and northern areas of the continent (e.g., the genera Parietaria, Olea, and Cupressus). Clinical and aerobiologic studies show that the pollen map of Europe is changing also as a result of cultural factors (e.g., importation of plants for urban parklands) and greater international travel (e.g., the expansion of the ragweed genus Ambrosia in France, northern Italy, Austria, and Hungary). Studies on allergen‐carrying paucimicronic or submicronic airborne particles, which penetrate deep into the lung, are having a relevant impact on our understanding of pollinosis and its distribution throughout Europe.
Background: Specific allergen from various pollen types has been found to be carried through the outdoor air, not only by intact pollen grains, but also by much smaller, paucimicronic particles. ...There is no complete agreement on whether, for birch (Betula), the seasonal appearance of atmospheric pollen allergen follows the fluctuation pattern of the pollen season.
Methods: Assessment of birch‐pollen allergen in size‐fractionated ambient aerosol was performed by descending elution of allergen from impaction strips of a five‐stage cascade impactor, and compared with atmospheric birch‐pollen concentrations as measured with a volumetric pollen trap.
Results: An overall similarity in the courses of the seasonal presence was found for both birch pollen and allergen in particles of all paucimicronic size fractions, although some airborne allergen was detected before and after the birch‐pollen season.
Conclusions: Transfer of pollen allergen to both natural and pollutant environmental dust particles is thought to be the probable explanation of secondary allergen carriage by paucimicronic particles. Until simple techniques for direct and rapid assessment of atmospheric pollen allergen become available, the pollen count gives sufficiently reliable information about the seasonal course of airborne pollen allergen.
Summary
In a study during the 1993 grass pollen season at Leiden, the relationship between atmospheric pollen allergen carried by five size fractions of pauci‐micronic (few microns) particles and the ...grass pollen count was investigated. Sampling was carried out on dry days, and atmospheric pollen allergen in the particle fractions was assessed by a RAST‐inhibition assay while grass pollen quantities were measured with a volumetric pollen trap. It appears that the atmospheric presence of grass pollen allergen in all size fractions is restricted mainly to the period of presence of grass pollen grains. Before and after the grass pollen season atmospheric grass pollen allergen quantities are generally very low. It is concluded that a routinely performed grass pollen count is a reliable measurement for the estimation of the amount of atmospheric grass pollen allergen, also in the pauci‐micronic particle fraction.
Summary
In June 1988, during the grass‐pollen season in Leiden, The Netherlands, outdoor airborne paniculate matter was collected and separated into fractions according to aerodynamic sizes ( 10μm, ...4·9–10μm, 2·7–4·9μm, 1·3–2·7μm, 0·6–1·3μm, 0·6μm), with a cascade impactor mounted on top of a high volume sampler. The different fractions were tested for the presence of grass‐pollen allergenic activity using a RAST‐inhibition assay: specific IgE‐antibody‐containing patient serum was applied on the particle‐loaded impaction strips, and the serum was recovered by descending elution for further analysis in the RAST. Simultaneously, continuous measurements were made of the airborne grass‐pollen concentration using a volumetric pollen trap. Sampling observations lasting 7–9 hr during a period with relatively high airborne grass‐pollen concentrations showed reliably detectable amounts of grass‐pollen allergen, not only in the first impaction stage where intact pollen were collected, but also in the lower stages collecting the smaller, paucimicronic and submicron atmospheric aerosol fraction. It is evident that this result has serious implications for the understanding of the bronchial symptoms frequently seen in hay fever patients on days with high pollen concentrations in the air.
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