居家灰塵之擦拭採樣方法與臺灣地區學童家中Der p 1過敏原分布

Abstract

過敏性疾病是一種受環境因素影響的常見疾病。自1970年代以來，許多研究報告指出，全世界過敏性疾病的盛行率持續在增加，臺灣地區過敏性疾病的盛行率也呈現相同的趨勢。塵蟎（House dust mite, HDM）是引起氣喘、過敏性鼻炎、異位性皮膚炎等各種過敏性疾病的主要過敏原，是過敏性疾病中持續存在的危險因子。塵蟎喜好生長於溫暖潮濕的地方，臺灣地處亞熱帶，氣候條件非常適宜塵蟎生長。在臺灣以歐洲室塵蟎（Dermatophagoides pteronyssinus）為最優勢蟎種，歐洲室塵蟎的第一型過敏原（Der p 1）有很強的致敏原性，可引起IgE介導的I型過敏反應而誘發氣喘。研究顯示暴露於HDM第一型過敏原（Der p 1＋Der f 1）的濃度大於2 μg/ g dust時會增加人體對塵蟎致敏的風險，暴露濃度大於10 μg/ g dust時，會增加喘鳴（wheeze）和呼吸急促（breathlessness）的危險性。

過去與塵蟎過敏原暴露相關的研究因需調查人員前往個案家中收集樣本，故往往會受到成本、人力和物力的限制，樣本量及採樣地區也因而受限。為解決此問題，在本研究中，我們採用了新型的擦拭法收集居家灰塵，並評估讓參與者自行依照採樣說明書收集灰塵的可行性。研究利用擦拭法評估臺灣20縣市（舊制）國小學童居家環境Der p 1塵蟎過敏原分布的情形，並比較此方法與傳統上研究人員至個案家中使用吸塵法收集灰塵、分析採集到的灰塵中的塵蟎過敏原濃度的差異。

本研究共計兩項實驗。實驗一為比較兩種採樣方法的差異性，此部分共計從14個家戶中收了56份居家樣本，其中10戶位於臺北地區，4戶位於高雄地區。研究結果顯示，使用吸塵法採集到的灰塵重量平均為69.78±80.25 mg，顯著高於擦拭法的37.52±48.54 mg（p = 0.01），不過使用兩種方法收集到的灰塵檢測出的Der p 1過敏原濃度無顯著差異（吸塵法的Der p 1過敏原濃度平均值為0.34±0.42 μg/ g dust，擦拭法的Der p 1過敏原濃度平均值為0.45±0.68 μg/ g dust，p = 0.45）。因此我們推論，若採樣點為地板或家具等堅硬固體的表面，擦拭法可作為傳統吸塵法的一個替代性採樣方法。至於擦拭法是否能進一步代表與致敏作用最相關的床上及枕頭的過敏原濃度，需進一步研究加以確認。

實驗二為調查臺灣地區國小學童居家環境Der p 1塵蟎過敏原的分布，研究對象為分布於（延用縣市舊制）之基隆市、臺北市、新北市、桃園市、新竹市、新竹縣、苗栗縣、臺中市、臺中縣、南投縣、嘉義市、嘉義縣、臺南市、臺南縣、高雄市、高雄縣、屏東縣、宜蘭縣、花蓮縣、臺東縣等20個縣市。本實驗使用自行採樣的方式，由學童之家長依照採樣說明書，使用除塵布擦拭客廳與小朋友的臥室內的桌面、櫥櫃、書櫃等家具頂面的灰塵。分析結果顯示，Der p 1過敏原濃度平均值為0.23±0.33 μg/ g dust，北部地區（南投以北）平均Der p 1過敏原濃度為0.27±0.37 μg/ g dust，顯著高於南部（嘉義以南）的0.19±0.28 μg/ g dust（p = 0.039）。影響因子方面，戶外的相對溼度越高，則客廳和臥室之家具頂面的灰塵內含的Der p 1過敏原濃度越高（p < 0.05）。全臺灣的戶外相對濕度均大於50%，已構成符合塵蟎孳生的條件，故家中使用除濕設備者偏多。另外父母親的教育程度在高中職以上者，家中的Der p 1過敏原濃度較教育程度在中學以下者低（p = 0.028）。在塵蟎過敏原對過敏性疾病的影響方面，本研究結果顯示高濃度暴露組（Der p 1≧0.28775 μg/ g dust）發生氣喘的勝算是低濃度暴露組（Der p 1<0.04017 μg/ g dust）發生氣喘的2.23倍。然在調整其他因子後，其統計相關性為邊緣性相關，故仍需進一步探討與確認。

Allergic disease is a common disease and affected by environmental factors. Since the 1970s, various studies have pointed out the continually increasing prevalence of allergic diseases in the world; allergic diseases in Taiwan also exhibits the same trend. House dust mite (HDM) is a major allergen that causes various allergic diseases, such as asthma, allergic rhinitis, and atopic dermatitis, and it is a persistent risk factor. Dust mites preferably grow in warm and humid places. Taiwan is located in a subtropical zone, and its climate conditions are suitable for the growth of dust mites. In Taiwan, Dermatophagoides pteronyssinus is the most dominant dust mite species. The first allergen group of Dermatophagoides pteronyssinus (Der p 1) features a strong allergenicity, and it can cause IgE-mediated type I allergic reactions and induce asthma. Studies have shown that exposure to Der p 1 and Der f 1 at concentrations higher than 2 µg/g dust increases the risk of sensitization to dust mites. Exposure higher than 10 µg/g dust concentrations increases wheezing and breathlessness.

Studies of indoor allergen exposures are often limited by the cost and logistics of sending technicians to homes to collect dust. The sample size and sampling area are thus constrained. Therefore, subject-collected dust sampling is a practical option for epidemiological and clinical studies in measuring environmental allergen exposure. In this study, we evaluated the feasibility of allowing participants to collect their own dust samples from desktops, bookcases, or cabinets in the living room and bedroom. We also compared the side-by-side dust samples by different methods, with one of each pair collected by a trained technician.

In the first study, we compared two sampling methods. A total of 56 household samples were collected from 14 households, of which 10 were located in Taipei and 4 were in Kaohsiung. The results showed that the average weight of the dust collected measured 69.78 ± 80.25 mg by vacuuming and 37.52 ± 48.54 mg by wiping. The average value of Der p 1 allergen concentration amounted to 0.34 ± 0.42 µg/g dust by vacuuming and 0.45 ± 0.68 µg/g dust by wiping. No significant difference (p = 0.45) was observed between the two collecting methods. We conclude that home collection using a wiping method of sampling in surfaces can be an alternative to vacuum sampling. Whether the wiping can represent the allergen concentration in the bed and pillow that is most relevant to sensitization requires further investigation.

A HDM survey of healthy, asthmatic, and allergic rhinitis schoolchildren was conducted. The children were enrolled from nationwide elementary schools between March 2016 and May 2017. The elementary schools are located in 20 cities and counties. The parents stayed at home and collected house dust. Dust samples were analyzed for allergen content by enzyme-linked immunosorbent assay for Der p 1. From 20 elementary schools, 334 students aged 6–12 years old were selected as candidates for the study. In their homes, the average Der p 1 concentration reached 0.23 ± 0.33 µg per gram of dust, whereas the average concentration of Der p 1 allergen totaled 0.27 ± 0.37 µg/g dust in the northern region, which was significantly higher than that in the southern region (0.19 ± 0.28 µg/g dust), p = 0.039. The dust mite levels from the top of furniture were negatively associated with parental education and positively associated with outdoor relative humidity. The average outdoor relative humidity in Taiwan is more than 50%, which is in line with the conditions of dust mites. Therefore, many people use dehumidification equipment at home. In terms of the effect of dust mite allergens on allergic diseases, the results of this study showed that the odds ration of asthma in the high exposure group (Der p 1 ≧0.28775 μg/g dust) was 2.23, compared with asthma in low exposure group (Der p 1<0.04017 μg/g). However, after adjusting other confounding factors, their statistical correlation is a marginally significant correlation. We still need to be further explored and confirmed.