IL17A and Crohn ileitis: TNF-α, nitric oxide and IFN-γ are all critical for development of necrosis in the small intestine and early mortality in C57BL/6 mice orally infected with high parasite load of ME-49 strain of T. gondii [2], and IL-17 is involved in ileitis in mice infected with cysts of the 76K strain by oral route [7,8].