Chulalongkorn Medical Journal


Problem/Background : House dust mites, Dermatophagoides pteronyssinus and D. farinaeare the most common among all mite species distributedworldwide. They are also the most common sources of allergenscausing asthma and other allergic diseases. Epidemiologicalstudies of these house dust mites are based on morphologicalidentification. This procedure faces some difficulties, includingrequirements of expertise to identify the mites and inability todiscriminate immature stages. Therefore, we applied the molecularmethod for discriminating between the two most common housedust mites, D. pteronyssinus and D. farinae.Objective : To demonstrate the usage of the cytochrome oxidase I (COI)gene for discriminating between D. pteronyssinus and D. farinaeby polymerase chain reaction-restriction fragment lengthpolymorphism (PCR-RFLP).Design : Descriptive study.Setting : Department of Parasitology, Faculty of Medicine, ChulalongkornUniversityMethods : The house dust mites; D. pteronyssinus and D. farinae, weremaintained at Faculty of Agricultural Technology, King Mongkut’sInstitute of Technology Ladkrabang, Bangkok, Thailand. The DNAextraction was amplified for COI gene by PCR technique.The DNA sequences were compared with GenBank database.As for PCR-RFLP analysis, the PCR products were digested inseparate reaction with AluI.Results : PCR yielded 1,559 and 1,562 bps for the COI gene of D.pteronyssinus and D. farinae respectively. AluI restriction digestionsof the PCR amplicons produce different RFLP patterns betweenthese house dust mite species.Conclusions : This technique provides accurate identification of the house dustmites which can be used for epidemiological surveys, and thereforeto perform diagnostic testing and for prescribing immunotherapymore efficiency.


Faculty of Medicine, Chulalongkorn University

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