ABSTRACT
Background: House dust mite (HDM) allergen quantification in house dust samples before and after the allergen elimination is one means of convincing the target population about the health benefits of allergen removal from their environment. Objective: To produce local reagents for quantification of Der f 1 (major allergen of Dermatophagoides farinae) in dust samples from houses of HDM allergic Thai patients. Methods: Recombinant Der f 1 was used for immunization of a BALB/c mouse for hybridoma production. Polyclonal antibody (PAb) to whole body extract of D. farinae was prepared from an immunized rabbit. A sandwich ELISA (MAb-allergen-PAb) was used, in comparison with the commercialized reagents (Indoor Biotechnology, UK), to quantify Der f 1 in dust samples. Results: Two hybridoma clones, Df1-1 and Df1-2, were established. Their secreted MAbs (MAbDf1-1 and MAbDf1-2, respectively) bound to the homologous antigen as well as native Der f 1 and a crude extract of D. farinae. Epitopes of MAbDf1-1 and MAbDf1-2 were located at amino acid residues 206NSQHYGISNYCQ217 and 283DYW---NSWD-WGDSG298 of Der f 1. MAbDf1-1 had higher affinity to Der f 1 than the MAbDf1-2. A sandwich ELISA (MAbDf1-1-allergen-PAb) and commercialized reagents (MAb1-allergen-MAb2 sandwich ELISA) were used in comparison for quantification of Der f 1 in 42 dust samples collected from bedrooms and living rooms of 21 houses of the HDM allergic patients. All of the 42 dust samples measured by both ELISAs had the Der f 1 levels higher than 2 mg per gram of fine dust which is the HDM allergy sensitizing level. In addition, Der f 1 levels in 41 samples (except 1 sample from a living room) measured by the MAbDf1-1-PAb and MAb1-MAb2 sandwich ELISAs were higher than 10 mg per g of dust which is the morbidity level of HDM allergen. The local sandwich ELISA showed a high coefficient correlation (r = 0.91) in measuring known amounts of recombinant and native Der f 1. The results indicate that the reagents produced in the present study can be used for measuring the environmental levels of HDM Der f 1. The assay can also be used for standardization of the HDM extract for monitoring patient's allergenic status or for immunotherapeutic purpose.
ABSTRACT
PURPOSE: The objective of this research is to provide the indoor environment management education program for the asthma patients and their families and then analyze the effectiveness in education preventing allergic asthma. METHODS: A pre-post single group quasi-experimental design was used to provide an education program about correct indoor environment management to a total of 58 households (29 patient households and 29 normal households). The performance rate of correct indoor environment management procedure, amount of house dust mite antigen, allergy subjective symptoms score and knowledge score about indoor environment management were compared before and after the education to test the effectiveness of the education. RESULTS: Home-visit education in this research had effects in improving subject households' performance rate of indoor environment management procedures, reducing the amount of house dust mite antigen - an important inducing factor of allergy, and reducing perceived subjective symptoms of allergy.