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.