TNF and inflammatory bowel disease: TNF may also play a role in extraintestinal manifestations (EIMs), which have been reported in up to 47% of patients with IBD.47 The musculoskeletal system is the most frequently affected, with peripheral arthritis and axial spondyloarthritis reported as the most common manifestations; other organs affected include the skin, bile duct and eyes.47 The exact pathogenic mechanisms relating to the development of EIM remain to be fully defined.