It might be speculated that B.hominis downregulates the host immune responses in the early phase of the infection, in order to improve its survival. This seems to be a common evasion mechanism of parasites, as it has also been demonstrated for Toxoplasma gondii (Denney et al. 1999). Further it may also be expected that this effect of B.hominis could indirectly facilitate the progress of infection by other opportunistic pathogens. The results presented here indicate that B.hominis is able to induce and modulate the production of inflammatory cytokines in intestinal epithelial cells.