[House-dust allergens. II. Correlations of intradermal reactions of house-dust extract and extract of "D. pteronyssinus"].

In a previous study we had found a high correlation between the positive reaction to standard house dust and to a mites pool extract of 0.86. The study had indicated that the dominant mite found in standard house dust in Barcelona seemed to be D. pteronyssinus. We wished to further confirm this finding by comparing skin reactions to an extract of this mite with skin reactions to the city's dust. A dust extract (HDS-B) was prepared according to the Spieksma technique in a proportion of W/V 1/10 and diluted to 1/1,000 with the liquid of the extract. Extracts of D. pteronyssinus were prepared with a culture medium (HDM), diluted to 1/1,000,000 and a control of thc culture medium at 1/100. A study was made of 56 children suffering from asthma due to house dust, their ages ranging from 4-14 years. 19 were eliminated due to positive reactions to the control. Among the remaining 37 a skin-reaction to histamine ratio was established. The correlation coefficient found was 0.91, which is significant at a level of P less than 0.001. It is also noteworthy that of the nineteen children (33.9%) who reacted to the control, 10 (17.85%) of them reacted positively with at least 2-3 crosses, which leads us to think that human dander may act as a lesser allergen. We therefore conclude that: 1. D. pteronyssinus is the principal source of allergen in domestic dust. 2. The precise role of human skin dander needs to be clarified.