TNF and inflammatory bowel disease: Various models of experimental IBD have been developed to investigate pathogenesis and to improve treatment options such as gene knockout (KO) models:interleukin (IL)-2/IL-2 receptor-alpha [4], IL-10 [5], T cell receptor [6], Tumor necrosis factor (TNF)-3′ untranslated region (UTR) [7] or transgenic models: IL-17 [8], HLA B27 [9].