Expression of SmATPDases 1 and 2 in Schistosoma mansoni eggs favours IL-10 production in infected individuals.

A role of IL-10 is down-regulating T-cell responses to schistosome antigens. Since SmATPDases can be correlated to modulation of the immune response, we evaluated the expression of enzymes in S. mansoni eggs. Faecal samples were collected from 40 infected individuals to detect coding regions of the SmATPDases. The cytokines were measured in supernatants of PBMC. The analysis was performed by the global median determination and set up high producers (HP) of cytokines. Six individuals expressed SmATPDase1, six expressed SmATPDase2 and six expressed both enzymes. The group who expressed only SmATPDase1 showed a high frequency of IFN-γ, TNF IL-4 HP; individuals who expressed only SmATPDase2 showed a high frequency of IFN-γ, IL-6 and IL-4 HP; and individuals who expressed both enzymes showed a high frequency of IL-10 HP. The comparison of the IFN-γ/IL-10 ratio presented higher indices in the group who had SmATPDase 2 expression than those who had the expression of both enzymes. The positive correlation between infection intensity and IL-10 levels remained only in the positive SmATPDase group. The IL-10 is the only cytokine induced by the expression of both enzymes. Our data suggest that the expression of both enzymes seems to be a factor that modulates the host immune response by inducing high IL-10 production.

Effect of chemotherapy with praziquantel on the production of cytokines and morbidity associated with schistosomiasis mansoni

The objective of the present study was to test the hypothesis that treatment of schistosomiasis mansoni with praziquantel can alter significantly the immune response of patients and generate a reversal of the level of fibrosis. Peripheral blood mononuclear cell (PBMC) samples were collected from, and abdominal ultrasound examinations conducted on, volunteers infected with Schistosoma mansoni and living in an area where the disease is endemic, both prior to and one year after treatment with praziquantel. Subjects were classified into groups according to the level of pathology (i.e., absent, incipient, moderate, or severe fibrosis). PBMCs were stimulated with schistosome soluble egg antigens (SEA), and the levels of production of the cytokines gamma interferon (IFN-gamma), tumor necrosis factor alpha, transforming growth factor beta, and interleukin-4 (IL-4), IL-10, and IL-13 were determined. The chemotherapy was effective in reducing morbidity, particularly for individuals presenting with severe fibrosis. When levels of cytokine production in posttreatment PBMC cultures stimulated by SEA were categorized as low or high, significant differences in the distribution of IL-13 levels between groups presenting with or not presenting with fibrosis were established. Comparison of pre- and posttreatment SEA-induced cytokine levels in individuals who had experienced no change in the grade of fibrosis following chemotherapy revealed that the level of IFN-gamma decreased in subjects with fibrosis whereas that of IL-10 decreased in individuals with and without fibrosis. The data suggest that chemotherapy is effective in reducing the morbidity of the disease and that the level of IL-13 may be a useful indicator of the persistence of fibrosis following treatment