CD4 and Hepatomegaly: At ~6 weeks post S. mansoni infection, mature female worms living in the portal vasculature are releasing eggs, the soluble Ags of which are highly immunogenic and promote Th2 responses.4, 7 Eggs that become trapped in the liver sinusoids cause dramatic changes to the overall liver microenvironment, including the development of granulomas, composed of CD4+ T cells, macrophages, eosinophils and CD11c+ DCs, around the individual eggs.4, 11 In our study, S. mansoni infection was associated with hepatomegaly and an increase in the total number of leukocytes in the liver (Figures 1b and c).