TNF and gastritis: Additionally, VacA modulates the host immune response by inhibiting the activation and proliferation of immune cells and stimulating the production of proinflammatory cytokines (e.g., TNF-α and IL-6) by mast cells to promote the development of H. pylori-associated gastritis, peptic ulcer disease and GC (Supajatura et al., 2002; Torres et al., 2007).