Comparative Study of Siriraj In-house Mite Extracts and Commercially Available Extracts

his study compared the quality of allergenic extracts produced from pure mite bodies (PMBs) and spent mite medium (SMM) of Dermatophagoides pteronyssinus (Dp) and D. farinae (Df), with commercially available extracts (FDA, Greer, CSL). It also evaluated the use of glycerine as a preservative, the stability of these extracts under various temperatures, and the reactions of allergy patients to skin-prick testing with these extracts. The concentrations of in-house extracts were determined by ELISA. The extracts were kept at 4°C and their concentrations measured for one year. Another batch of in-house extracts, stored with or without glycerine, was exposed to multiple refrigeration in-out cycles. PMBs yielded significantly greater concentrations of allergen than SMM, while in-house Der f1 was greater than Der p1 in allergenic concentration, regardless of time, equal to the FDA extract and significantly greater than the Greer extract. Glycerine was largely ineffective. There were insignificant differences in allergy patients' reactions to skin-prick tests. It may be concluded that PMBs, rather than SMM, should be used as source material for generating mite allergen extracts.