New insights into immune mechanisms underlying autoimmune diseases of the gastrointestinal tract.

Recent progresses in the immune mechanisms implicated in chronic inflammatory disorders have led to a more in-depth knowledge of the pathogenesis of autoimmune diseases of the gastrointestinal tract, including autoimmune atrophic gastritis, celiac disease, autoimmune enteropathy and ulcerative colitis. While the pathogenic role of specific circulating autoantibodies, i.e., respectively anti-parietal cell, anti-tissue transglutaminase, anti-enterocyte and anti-neutrophil cytoplasmic, is still controversial, some common T-cell mediated mechanisms for inflammation - increase in T helper cell type 1/type 17 pro-inflammatory cytokines- or losing self-tolerance-abnormal regulatory T cell function - are recognized as crucial mediators of the tissue damage causing atrophy of the stomach mucosa in autoimmune atrophic gastritis, villous flattening of the small bowel in celiac disease and autoimmune enteropathy, and mucosal ulceration of the colon in ulcerative colitis. This review deals with novel advances in the immunological bases of the aforementioned autoimmune gastrointestinal disorders, and it also highlights immune mechanisms of progression from chronic inflammation to cancer and implications for new therapeutic targets.