Studies on Dermatophagoides pteronyssinus allergens: measurement of the relative potencies of D. pteronyssinus purified extracts by in vitro and in vivo methods.

To standardize the Dermatophagoides pteronyssinus extracts used in clinical allergy practice, the relative potencies of several purified extracts were estimated by radioallergosorbent test (RAST) inhibition, histamine release, and intracutaneous titration testing, and the results were compared. The potencies of nine independently prepared D. pteronyssinus extracts were assayed with respect to an extract adopted as a reference. In vivo the cutaneous wheal surface after intradermal injections was measured on a population of D. pteronyssinus-sensitive subjects. In vitro RAST inhibition was performed with the reference extract as allergosorbent and with a pool of human IgE-rich sera from patients sensitized to D. pteronyssinus but untreated. For histamine release human basophils from patients allergic to D. pteronyssinus were used. In the three method dose-response curves were plotted for the reference extract and the other extracts. A comparison of the measurement of in vitro and in vivo potencies is reported. Simialr results were obtained with the three methods: all the extracts but one were as potent as the reference preparation. However, for routine purposes RAST inhibition appears to be the most convenient and reliable procedure.