Abstract: Objective To investigate the level of indoor dust mite allergens in residential homes in Shanghai. Methods The allergenic proteins, Dff F3 and Der fⅢ (well known allergen) from the whole culture extract of Dermatophagoides farinae were purified by chromatography and sedimentation techniques. Allergic activities of both proteins were identified by skin prick test and RAST. After preparation of specific IgG anti-Dff F3, anti-Der fⅢ, and extraction of indoor allergens from 200 indoor dust samples collected from residential homes, the allergen concentration was measured by sandwich ELISA. Allergen level was expressed in geometric mean and range, the analysis of variance (ANOV) was used to determine the level of significance between groups. Results Dff F3 and Der fⅢ were demonstrated strongly allergic activities, which can be highly recognized with IgE from sera of the mite-allergic patients with asthma. In the sampled 200 homes, the proportion of homes with Dff F3 level of >10 μg/g was 57.0%, 29.5% for group of 2-10 μg/g, and 13.5% for group of <2 μg/g. The proportion of homes with Der fⅢ level of >10 μg/g was 53.5%, 32.0% for group of 2-10 μg/g, 14.5% for group of <2 μg/g. Conclusion Selected residential homes in Shanghai were found more likely to have high level of dust mite allergens. Dff F3 was identified as the stronger allergic fraction.

Key words: Dermatophagoides farinae, Allergen, Indoor