A comparative study of the major allergenic components in house dust extracts between siriraj and commercially prepared extracts.

ABSTRACT

The quantity and concentration of major allergens in mite allergenic extracts are crucial for skin testing, which is the recommended standard method for the diagnosis of house dust mite allergic disease. The purposes of this study were 1) To compare the constituents of major mite allergens in 3 types of mite extracts, i.e., extracts from mite reared in-house (Dermatophagoides pteronyssinus and Dermatophagoides farinae), extracts from commercial mite products and commercial ready-made mite extracts. These in-house extracts were prepared either with or without the preservative, glycerine. The concentrations of the major constituents of group 1 and 2 allergens of the extracts were determined by a two-site monoclonal based ELISA. 2 ) Biological assays were also carried out to determine the relative potency of the extracts in 120 allergic patients by skin prick test. It was found that the mean concentrations of Der p1, Der f1 and group 2 mite allergens in extracts from mites reared in-house were 102, 195 and 94 ตg/ml, respectively, compared to 169, 238 and 91 ตg/ml, respectively in commercial mite extracts. The commercial with product had the lowest concentrations of mite allergens (1 ตg/ml). Comparison of mite extracts with and without glycerine preservative showed no significant difference in concentrations of major allergens. Reduction of allergens concentration from 10,000 to 1,000 PNU/ml also reduced the concentration of mite allergen proportionately. Siriraj mite extracts were stable for at least 1 year at 4 oC without any significant change in composition or concentration. In conclusion, mite reared in-house can be used as raw material for preparation of mite allergenic vaccine.