ITGA4 and inflammatory bowel disease: Currently, several novel biologic agents including ustekinumab (human monoclonal antibodies block IL-12 and IL-23), natalizumab (humanized monoclonal antibody against alpha-4 integrin) and vedolizumab (humanized monoclonal antibody against alpha-4-beta-7 integrin) have been developed for potential use in the management of IBD (85).