In this study, we showed that AQP4 deficiency leads to an increase in differentiation of Th2 cells but a decrease in differentiation of both Th1 and Treg cells during S. japonicum infection, and for the first time suggested a possible role of AQP4 in the immunoregulation of the liver pathogenesis in schistosomiasis. The gene discussed is AQP4; the disease is schistosomiasis.