Autoimmunity and diet.

Whether diet may influence autoimmunity has been the subject of many unsolved debates. Interestingly, growing evidence indicates a large overlap between the mechanisms controlling tolerance to dietary antigens and autoimmunity. To discuss these links, we will focus on two model human diseases. The first one is IPEX syndrome due to mutations in the X-linked foxp3 gene. Studies of this disease underscore the role of regulatory FOXP3+ T cells in controlling the reactivity against self antigens and the response to dietary proteins in humans. The second is celiac disease, a complex poly-genic disease where exposure to dietary wheat proteins can trigger an autoimmune-like attack of the intestine frequently associated with the onset of extra-digestive autoimmune disorders. In the later disease, recent work shed light on the mechanisms that drive the intestinal inflammatory response to gluten and suggests impairment of immunoregulatory mechanisms that control intestinal tolerance and autoimmunity. Yet the exact role of gluten in the pathogenesis of extra-intestinal autoimmunity has not been elucidated. Interestingly, recent work indicates that dietary factors, including vitamin A and breast milk feeding, can protect against the development of harmful responses to dietary proteins. It is unclear whether this protection can apply to the prevention of autoimmunity.