| Summary: | 碩士 === 國立成功大學 === 環境醫學研究所 === 96 === Pollens are known as major allergens in the atmosphere while increasing prevalence and mortality of asthma and rhinitis has been observed around the world. Previous pollen monitoring in Tainan City of Taiwan had revealed that Broussonetia papyrifera could be a major genus, about 40%, in Taiwan, and literatures have reported that allergic symptoms could be induced by exposure to pollens of Broussonetia papyrifera. This study was therefore aimed to assess whether Broussonetia papyrifera pollen in atmosphere could be a seasonal allergen in Taiwan. Daily pollen counts were achieved by collecting pollen spores using a Burkard trap. The size of Broussonetia papyrifera pollens, between 10μm-12μm, was smaller than many prevalent types of pollen, and might be easier to penetrate through respiratory track after inhalation. Our study has analyzed first, using generalized addictive models (GAM) with Poisson regression model, the associations between the levels of daily Broussonetia concentration, about 32% of the total pollens measured, and frequencies of daily clinic visits and hospital admission in a major teaching hospital from 1 January to 31 December in 2005. Time-series analysis, having filtered the seasonal trends and adjusted for the day-of the week cycles, weather factors, and air pollutants, was conducted to determine the influence of ambient spores on asthma hospital admissions. The strongest association was observed for effect of ambient Broussonetia concentrations on the number of clinical visits hospital admission (respiratory tract disease clinic visits (RR=1.142), allergic rhinitis clinic visits (RR=1.206), Asthma clinic visits (RR=1.160) and respiratory tract disease hospital admission (RR=1.137). Fresh pollens of Broussonetia papyrifera were then collected from trees during March to May, the flowering season, for extraction before identical analysis was conducted with commercial pollens (Allergen AB, Sweden) for comparison. Serum of 20 allergic asthmatics (median level of total IgE=580.50 EU/L) and 20 healthy schoolchildren (median level of total IgE= 17.65 EU/L), together of 40 with 21 males and 19 female aged between 7~12 years old, were analyzed for the specific IgE levels after challenged with Broussonetia papyrifera extract, both of fresh ones and commercial preparation. Furthermore, 30 volunteer subjects (12 males and 18 female; aged between 23~38 years old) were recruited for skin prick test (SPT) and the specific IgE analysis to Broussonetia papyrifera by Enzyme-Linked ImmunoSorbent Assay (ELISA). The mean soluble protein content of the fresh pollens extract of was observed at 0.29 mg/ml of the 1:100 (w/v) concentrations. Specific IgE levels measured in subjects when exposed to fresh pollen extract correlated well with those measured after exposure to commercial pollen extract (spearman correlation= 0.89, p<0.01). OD value of specific IgE levels in schoolchildren with allergic asthma was higher than that of healthy children (median value 0.035 v.s 0.025, p<0.05). Using sera from a general population, among 3 different allergen levels used for SPT, the only significant difference, when compared the negative versus the positive response group, that could be consistently supported by the measurements of total IgE (median value of 50.6 ku/L for negative and 120.0 ku/L for positive SPT) and specific IgE level (median value of 0.027 for negative and 0.064 for positive SPT) was at the concentration of 10 μg/ml (46% sensitized rate). The allergic characteristic of Broussonetia papyrifera pollens is supported by tests on both school-aged children as well as young adults based on not only the specific IgE analysis but also the skin-prick-test, and therefore suggested to be one important emerging allergen in Taiwan.
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