TNF and inflammatory bowel disease: In fact, IL-17 increases the expression of pro-inflammatory cytokines, including IL­6 and TNFα, chemokines, such as the keratinocyte chemoattractant (KC), MCP-1 and MIP-2, and matrix metalloproteases, all of them involved in tissue infiltration and tissue damage [29], and thus revealing a crucial function in the pathogenesis of human IBD [30].