title: The opposing roles of IL-21 and TGFβ1 in chronic inflammatory bowel disease.
abstract: There are large numbers of T-cells in the mucosa of the intestine in healthy individuals. The stimulus for their presence is the normal gut microbiota. For unknown reasons, in patients with IBD (inflammatory bowel disease), there is inappropriate and chronic activation of mucosal T-cells which leads to gut damage and severe morbidity. In one form of IBD, namely Crohn's disease, the T-cells are probably responding to the microbiota. T-cell survival in the gut wall is dependent on pro-inflammatory cytokines and antibody-mediated inhibition of one of these cytokines, TNFα (tumour necrosis factor α), has shown efficacy in patients, thus encouraging investigations of other ways to control mucosal T-cell responses. In the present paper, we give a brief review of T-cell immunology in IBD and then discuss how two particular cytokines, namely IL-21 (interleukin 21), which is generally pro-inflammatory and important in gut T-cell survival and in maintaining Th17 cells, and TGFβ1 (transforming growth factor β1), which is generally immunosuppressive, play opposing roles in gut inflammation.
authors.affiliation: Centre for Immunology and Infectious Disease, Barts and the London School of Medicine and Dentistry, 2 Newark Street, London E1 2AT, UK. t.t.macdonald@qmul.ac.uk
authors.forename: Thomas T
authors.initials: TT
authors.lastname: MacDonald
authors.forename: Iona
authors.initials: I
authors.lastname: Bell
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
mesh_terms: D000818:Animals; D006801:Humans; D007113:Immunity, Innate; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D020381:Interleukin-17 / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D000098546:Interleukin-21
chemical_list: C508717:IL17A protein, human; D020381:Interleukin-17; D007378:Interleukins; D053773:Transforming Growth Factor beta1; D000098546:Interleukin-21