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.

IL-10, IFN-gamma and TNF-alpha in acute and chronic human fascioliasis.

The three cytokines, IL-10 (Th2 product), IFN-gamma (Th1 product) and TNF-alpha work in concert. The present work was undertaken to study the level of these cytokines during the acute and chronic stages of human fascioliasis in an attempt to assess the involvement of Th1 and Th2 cells in regulation of the immune response in this disease. Sera of twenty six Fasciola patients were obtained and divided into two groups: twelve with acute and fourteen with chronic fascioliasis, sera of a control group were studied simultaneously. During the acute stage, a significant increase was observed in IL-10, IFN-gamma as well as TNF-alpha and specific antibody level. In the chronic phase, a significant increase of IL-10 level was observed. IFN-gamma showed a lower level as compared to the acute stage but TNF-alpha was still high. Accordingly, in fascioliasis in the early phase of infection B cells, macrophages, Th1 and Th2 cells were all activated. They cooperate in overcoming the parasite and work to the benefit of the host. With time and after maturation of the evading worms, Th2 action predominates. IL-10 (Th2 cytokine) which is antagonistic to IFN-gamma (Th1 product) and consequently to TNF-alpha limits the immunopathology that may be caused by the latter.

Immunological and histopathological studies on the effect of toxoplasmosis in experimental schistosomiasis.

One hundred and twenty Swiss albino mice were infected with avirulent strain of Toxoplasma gondii. Then challenged with Schistosoma mansoni at different time intervals of one week, one month and two months. The immunological and histopathological changes were assessed for each mouse. The results showed that toxoplasmosis caused specific humoral and cellular immunosuppression to Schistosoma mansoni infection.

Assessment of interleukin-1 activity of peritoneal macrophages in mice infected with Schistosoma mansoni before and after praziquantel administration.

This work was devoted to clarify the changes in interleukin-1 (IL-1) activity of peritoneal macrophages in mice experimentally infected with S. mansoni before and after praziquantel administration. A significant increase in (IL-1) activity after praziquantel administration was detected. These findings clarify the role of praziquantel in improving the immune state of the infected host.