TNF and inflammatory bowel disease: IBD is normally associated with chronic inflammation induced by infiltration of immune cells in the colon, including macrophages, neutrophils, T helper 17 (Th17) cells, and type 1 T helper (Th1) cells, resulting in the secretion of the proinflammatory cytokines interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ) [10–12].