The house-dust mite (Dermatophagoides pteronyssinus) and the allergens it produces. Identity with the house-dust allergen

Abstract Since the discovery of the house-dust allergen around 1920, many investigators have sought its origin. What puzzled them most was its occurrence in such indefinable material as house dust, its remarkable specificity, and the fact that so many asthma patients were atopic to it. A theory on the origin of the house-dust allergen must account for the following factors: (1) its ubiquitous occurrence, which is in fact world wide; (2) its specificity; (3) the seasonal variation in the allergen content of the dust (with an autumnal peak), which suggests that the house-dust allergen is the result of a biological process; and (4) the quantitative element: the house-dust allergen must be produced by the causal factors in huge quantities. The finding of the house-dust mite, Dermatophagoides pteronyssinus , seems to supply an answer to all these factors: (1) Although in varying numbers, this particular species of mite has been found in all dust samples from many different countries. (2) The allergen produced by it is highly specific. (3) The number of mites in house dust shows a seasonal periodicity with a peak in autumn. (4) Mite cultures contain so much allergen that extracts diluted even to 0.000001 per cent still give skin reactions in persons sensitive to house dust. Finally, the keystone of the theory is formed by the fact that after being made equivalent, extracts of house dust and mite cultures gave skin reactions which were both qualitatively and quantitatively indistinguishable.