TNF and inflammatory bowel disease: Although the etiology of IBD remains unknown, mucosal immune and non-immune cells in the inflamed gut of IBD patients spontaneously release pro-inflammatory cytokines such as TNF-α, interferon gamma (IFN-γ), interleukin (IL) 1 beta (IL-1β), IL-6, IL-8, and IL-12, which play a central pathologic role in IBD [29].