One of house dust mites, dermatophagoides farinae, was considered one of the most important allergen contained in house dust from the skin test, inhalation provocation test, P-K test and fractionation by Sephadex. This was further confirmed by neutralization test and RAST.
36 species of mites weres detected in house dust but D. farinae and D. pteronyssinuswere found the important allergens among them, although there were cross allergenicity in 7 species of house dust mites studied. Allergenic potency of house dust was largely determined by the number of mite contained. Four major allergens were found in D. farinae extract to react with IgE antibody by autoradiography and were named Me₁, Me₂, Me₃ and Me₄.
Titer of IgE antibodies against them differs in each patients and appears somewhat to relate with different atopic diseases. Co-culture of T and B cells from mite sensitive patients and normal subjects showed that the suppressor activity of T cell was impaired or helper activity was enhanced to produce IgE antibody against mite in atopic patients.
Further studies showed that IgE antibody was partly produced by radioresistant long lived B cell and this appeared the reason why IgE antibody lasts long although half life of IgE is about 3 days.