Abstract
Patch test and scratch-patch test with Finn chambers (Paijala, Hyrylä, Finland), using pulverized live mites and dried dead mites including Dermatophagoides pteronyssinus, D farinae and Tyrophagus putrescentiae without any vehicle were given to 49 atopic dermatitis (AD) patients. Only live mites induced a positive reaction in 11 cases. Fifteen controls composed of dermatitis patients other than AD gave only negative results. Female mites induced more positive reactions than males at a ratio of 8:1, and only D pteronyssinus (11 cases) and Tputrescentiae (4 cases) gave positive reactions. Based on the pathological manifestations (spongiosis, infiltration of lymphoid cells and eosinophiles in the upper dermis), type IV hypersensitivity to mite components was suspected. To identify the mite components that produce contact hypersensitivity, lipid was extracted from D pteronyssinus (Dp-L), D farinae (Df-L), and the mixed feeds (LC). Patch tests and scratch-patch tests were again performed and gave positive reactions only to Dp-L in both AD and non-AD patients (three cases each). Histological examination of the positive reactions revealed the same findings as in the pulverized mites. Leu-6 positive cells were noted frequently in the dermis. The lipid components of Dp-L were mostly phospholipid and triglyceride. Lipoprotein was not present. Therefore, it seemed necessary to study not only mite proteins or fecal proteins but also lipids to determine the allergenic components in mites that are responsible for AD.
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