While previous reports suggested that CD4+ T cells primarily mount Th1 responses to worm antigens during pre-patent infection [7,13], we recently showed that schistosome worms also induce IL-4-producing CD4+ T cells during pre-patent infection, which could therefore serve as a source of Th2 help for the IgE response demonstrated in Figure 2. The gene discussed is IGHE; the disease is infection.