Quality parameters for the production of mite extracts

Mites present in house dust are of great etiological importance in type I hypersensitivity, with those belonging to the Dermatophagoides genus (D. pteronyssinus and D. farinae), of the Pyroglyphidae family, being the most frequent and principal source of allergens. For the production of allergenic extracts destined for specific diagnostic and treatment purposes of allergic diseases, the culture of such mites is absolutely necessary. In accordance with studies carried out in our laboratories to obtain adequate extracts, one must bear in mind the culture mite phase. Three growth phases have been distinguished for both species: latency phase (F1), growth phase (F2) in which the allergenic proteins are expressed with greater intensity, and death phase of the culture (F3). In the same study, the biological standardization of the extracts demonstrated that those produced from the maximum growth phase gave both in vitro and in vivo results, at least three times more sensitive than those from the other phases. We checked the reproducibility of the production method, obtaining different batches in similar conditions with a high homogeneity regarding allergenic activity. The sensitivity and specificity of the allergenic extracts depends just as much upon the production method as the standardization method. During the biological cycle of Dermatophagoides in culture, it is only from the maximum growth phase (F2), that allergenic extracts with an excellent diagnostic value, high sensitivity and specificity, can be obtained.