Advances in the understanding and management of autoimmune enteropathy

There have been real advances in understanding the pathogenesis of autoimmune enteropathy, including determination of specific autoantigens. The most important clinical association is with IPEX (X-linked immune polyendocrinopathy) syndrome, which is due to mutation in the Foxp3 transcription factor, a molecule critical in generation of regulatory T cells. Association of non-IPEX autoimmune enteropathy with T cell activation defects further point to impairment of T cell tolerance mechanisms as the primary underlying cause of autoimmune enteropathy. This also explains the frequency of other autoimmune manifestations. The centrality of T cell responses in autoimmune enteropathy, rather than B cell autoantibody production, as previously thought, is further suggested by the finding of late-onset gut autoimmunity in APS-1 (autoimmune polyglandular syndrome-1), a condition where negative selection of T cells within the thymus is disrupted due to mutation in the Aire (autoimmune regulator) gene. However, this form of autoimmune enteropathy is milder because the immune target is within entero-endocrine cells rather than absorptive enterocytes. There have also been important changes in management, with introduction of more potent immunoregulatory therapy, and more recently the use of bone marrow transplantation, which may theoretically offer hope of a cure in what frequently used to be a fatal condition.