Isolation of dust mites from houses of Egyptian allergic patients and induction of experimental sensitivity by Dermatophagoides pteronyssinus.

Six house dust mite (HDM) species were isolated from dust of floors and mattresses of allergic patients houses in Alexandria. Dermatophagoides pteronyssinus (D.p.) was the dominant species in dust of floors and mattresses with average percentages of 68.9% and 78.3% respectively. It was used to induce experimental sensitivity in Swiss albino mice by repeated weekly intranasal instillation of D.p. mites in phosphate buffer saline (PBS). Cytological examination of bronchoalveolar lavage (BAL) fluid of mice revealed prolonged eosinophilia, that peaked on day 28 of the experiment and persisted till the end of the study. Blood eosinophilic counts were progressively increased during the course of the experiment. Histopathological findings showed evident eosinophilic infiltration in nasal and lung tissues of the sensitized mice. Specific IgE response to D.p. was progressively increased, reaching 30 times higher than the control group on day 42. The detected levels of interluekin-4 (IL-4) were in accordance with immunoglobulin response. D.p. provoked severe allergic response and this may help to design an effective therapy to ameliorate such allergic diseases.