Custovic A, Simpson A, Woodcock A
North West Lung Centre, Wythenshawe Hospital, Manchester, UK.
Allergy. 1998;53(48 Suppl):115-20. doi: 10.1111/j.1398-9995.1998.tb05011.x.
During the last few decades, many countries have experienced an increase in the prevalence and severity of asthma. Over the same period, the population in the developed world has retreated indoors, and homes have become better insulated and more energy efficient, resulting in a warm and humid environment with low ventilation rates, ideally suited to house-dust-mite population growth throughout the year. Increasing exposure and increasing sensitivity to indoor allergens represent a progressively higher risk factor for the development of asthma. The development of sensitivity to indoor allergens and the symptoms and severity of asthma in later childhood are directly related to the exposure to allergens in infancy. It was relatively straightforward to demonstrate a quantitative linear dose-response relationship between exposure to house-dust-mite allergens and subsequent sensitization. However, showing the same for exposure and asthma severity has been more difficult, as the relationship between exposure and asthma symptoms in already sensitized individuals is much more complex than in the case of exposure and sensitization. Nevertheless, sensitized individuals are likely to have more severe asthma if exposed to high allergen levels than if their level of exposure is low. Sensitization to house-dust mites is a major independent risk factor for asthma in all areas where climate is conducive to mite population growth. The relevance of allergens other that mite is not consistent between different areas, and depends on the climate, habits, and socio-economic features of the local community. It would appear that presence of mite allergens in homes "overshadows" other allergens (e.g., cat, dog, or cockroach) as a risk factor for sensitization and subsequent development of allergic disease. It is possible that this is the consequence of the difference in inherent potency between allergen sources, and the question of why mite allergens are so potent in inducing sensitization and atopic disease remains to be answered.
在过去几十年中，许多国家哮喘的患病率和严重程度都有所上升。在同一时期，发达国家的人口更多地待在室内，房屋的隔热性更好，能源利用效率更高，导致室内环境温暖潮湿，通风率低，非常适合全年屋尘螨的繁殖。对室内过敏原的接触增加以及对其敏感性增强，成为哮喘发病风险日益增高的一个因素。儿童后期对室内过敏原的致敏情况以及哮喘的症状和严重程度，与婴儿期接触过敏原直接相关。要证明接触屋尘螨过敏原与随后的致敏之间存在定量线性剂量反应关系相对比较容易。然而，要证明接触过敏原与哮喘严重程度之间也存在同样的关系则困难得多，因为在已经致敏的个体中，接触过敏原与哮喘症状之间的关系比接触过敏原与致敏之间的关系要复杂得多。尽管如此，与低暴露水平相比，致敏个体如果暴露于高过敏原水平，哮喘可能会更严重。在所有气候适宜螨虫繁殖的地区，对屋尘螨致敏都是哮喘的一个主要独立风险因素。不同地区其他过敏原（而非螨虫）的相关性并不一致，这取决于当地社区的气候、习惯和社会经济特征。家庭中存在螨虫过敏原似乎“掩盖”了其他过敏原（如猫、狗或蟑螂过敏原），成为致敏及随后发生过敏性疾病的一个风险因素。这可能是过敏原来源内在效力差异的结果，而螨虫过敏原为何在诱导致敏和特应性疾病方面如此强效的问题仍有待解答。
