Celiac disease and autoimmunity.

Celiac disease (CD) has a multifactorial etiology with complex genetics and frequently occurs in association with other autoimmune disorders. Even though triggered by a dietary antigen, it shows many autoimmune features, the most peculiar being the presence of high titers of anti-tissue transglutaminase 2 autoantibodies, produced in the small intestinal mucosa since the early stages of the disease. More than 60% of CD-associated susceptibility loci are shared with at least another autoimmune condition, suggesting common pathogenic mechanisms. In particular, recognition of peptides by HLA molecules, posttranslational modifications required for optimal peptide binding and immune mechanisms leading to tissue damage have been found in CD as well as in other autoimmune diseases. This review briefly summarizes the main autoimmune features of CD, underlining the similarities with other autoimmune disorders, in particular with type 1 diabetes mellitus. Furthermore, the role of gluten and microbiome in driving autoimmunity is discussed.