The study for the relationship between the quantity of Ascaris antigen in the house dust and asthma symptoms of children living in the rural area of Bangladesh

所谓卫生假说，是指卫生环境越好，过敏性疾病就越少。这一假设仍然存在争议，特别是在蛔虫感染主要是地方性流行的发展中国家。我们发表了一篇关于流行病学数据的论文，显示孟加拉国儿童喘息的发病率约为16%。孟加拉农村地区蛔虫感染率高达70%以上。我们的数据让这个问题与卫生假说背道而驰。我们还发现，高水平的抗蛔虫IgE抗体与喘息发作的发病率显著相关，诊断为支气管哮喘。我们推测屋尘中可能存在蛔虫抗原，作为吸入性过敏原。我们在孟加拉农村调查了与2001年调查相同的田野。2001年142例喘息组中61例(43%)10年后仍有喘息发作，97例非喘息组中79例(81%)无喘息发作。经卡方检验，差异有统计学意义(P&lt；0.0001)。从这两组人的被窝中收集屋尘。喘息组屋尘中蛔虫抗原含量(5.2 5μg/g粉尘，1.15~9.36，95%CI)高于非喘息组(2.5 4μg/g粉尘，1.6 7~3.4 1，95%CI)，但差异无统计学意义。新开发的检测蛔虫抗原的方法有一定的局限性，因为从日本房屋收集的灰尘中检测到了一些东西。我们的结果提示，在两个国家采集的室内粉尘中，可能存在蛔虫抗原以外的交叉反应物质。还需要进一步的研究。

So-called hygiene hypothesis means that better hygienic environment introduce less allergic diseases. This hypothesis is still controversial especially in the developing country where the ascaris infection is mostly endemic. We had published a paper concerning the epidemiological data which showed the morbidity of wheezing is about 16% in Bangladeshi children. The morbidity of ascaris infestation is over 70% in the rural area in Bangladesh. Our data threw the issue against the hygiene hypothesis. We had also showed that high amount of anti-ascaris IgE antibody significantly correlated to the morbidity of wheezy episodes, diagnosed as the bronchial asthma. We hypothesized there might be ascaris antigen in the house-dust which worked as the inhalant allergen. We surveyed the same field in the rural Bangladesh as the one surveyed in 2001.ISAAC questionnaire was used. Sixty one children out of 142(43%) who were wheezy group in 2001 showed wheezing episode yet after 10 years and 79 out of 97(81%) who were not wheezy showed no wheezing episode. This difference was statistically significant by chi square test(p<0.0001). House dust was collected from the bedding of these two groups. Higher amount of ascaris antigen(5.25μg/g dust, 1.15～ 9.36, 95% CI) was detected in the house dust of the wheezy group than the non-wheezy group(2.54μg/g dust, 1.67～ 3.41, 95% CI), although statistically not significant. The newly developed method for detecting ascaris antigen has some limitation, because something was detected from the dust which was collected from Japanese housing. Our result suggested that there might be cross-reactive materials other than ascaris antigen in those house dust collected from two countries. Further research is needed.