Division of Environmental Dermatology and Allergy, Helmholtz Zentrum München/TUM, ZAUM - Center for Allergy and Environment, Technische Universität München, Munich, Germany.
Allergy. 2010 Jul;65(7):850-8. doi: 10.1111/j.1398-9995.2009.02286.x. Epub 2010 Feb 4.
Proof is lacking that pollen count is representative for allergen exposure, also because allergens were found in nonpollen-bearing fractions of ambient air.
We monitored simultaneously birch pollen and the major birch pollen allergen Bet v 1 in different size fractions of ambient air from 2004 till 2007 in Munich, Germany.
Air was sampled with a ChemVol high-volume cascade impactor equipped with stages for particulate matter (PM)>10 microm, 10 microm>PM>2.5 microm, and 2.5 microm>PM>0.12 microm. Allergen was determined with a Bet v 1-specific ELISA. Pollen count was assessed with a Burkard pollen trap. We also measured the development of allergen in pollen during ripening.
About 93 +/- 3% of Bet v 1 was found in the PM > 10 microm fraction, the fraction containing birch pollen. We did not measure any Bet v 1 in 2.5 microm > PM > 0.12 microm. Either in Munich no allergen was in this fraction or the allergen was absorbed to diesel soot particles that also deposit in this fraction. Pollen released 115% more Bet v 1 in 2007 than in 2004. Also within 1 year, the release of allergen from the same amount of pollen varied more than 10-fold between different days. This difference was explained by a rapidly increasing expression of Bet v 1 in pollen in the week just before pollination. Depending on the day the pollen is released during ripening, its potency varies.
In general, pollen count and allergen in ambient air follow the same temporal trends. However, because a 10-fold difference can exist in allergen potency of birch pollen, symptoms might be difficult to correlate with pollen counts, but perhaps better with allergen exposure.
缺乏花粉计数能代表过敏原暴露的证据，这也是因为过敏原存在于环境空气中无花粉的部分。
我们在 2004 年至 2007 年期间在德国慕尼黑同步监测不同大小的环境空气中的桦树花粉和主要桦树花粉过敏原 Bet v 1。
使用配备用于颗粒物（PM）> 10 微米、10 微米> PM > 2.5 微米和 2.5 微米> PM > 0.12 微米的阶段的 ChemVol 大容量级联冲击器采集空气样本。过敏原通过 Bet v 1 特异性 ELISA 确定。花粉计数用 Burkard 花粉陷阱评估。我们还测量了花粉在成熟过程中的过敏原发育。
大约 93 +/- 3%的 Bet v 1 存在于 PM > 10 微米的部分，这是含有桦树花粉的部分。我们在 2.5 微米> PM > 0.12 微米的部分中没有测量到任何 Bet v 1。要么在慕尼黑，这个部分中没有过敏原，要么过敏原被吸收到柴油烟尘颗粒上，这些颗粒也沉积在这个部分中。2007 年，花粉释放的 Bet v 1 比 2004 年多 115%。即使在 1 年内，同一数量的花粉在不同日子之间的过敏原释放也会有 10 倍以上的差异。这种差异是由于在授粉前的一周内花粉中 Bet v 1 的表达迅速增加而引起的。根据花粉成熟期间释放的日期，其效力可能会有所不同。
一般来说，花粉计数和环境空气中的过敏原遵循相同的时间趋势。然而，由于桦树花粉的过敏原效力可能存在 10 倍的差异，因此症状可能难以与花粉计数相关联，但也许可以更好地与过敏原暴露相关联。
