IGHE and bacterial infectious disease with sepsis: Moreover, intestinal mastocytosis and bacteremia in Plasmodium yoelii yoelii 17XNL–infected mice were associated with the early appearance of IL-4, IL-18, MC protease (Mcpt)4, and basophils in plasma, followed by elevated levels of IgE, IL-9, IL-13, and Mcpt1, mediators that can maintain and enhance MC activation (9).