IFN-γ has been reported to be an important mediator of the immunopathology induced by chronic Helicobacter infection [4, 7, 9, 13, 36, 37] and may also be important for Helicobacter clearance, but the findings are not conclusive [4, 10, 13, 23]. Here, IFNG is linked to Helicobacter pylori infectious disease.