Autoimmune Polyendocrine Syndromes

Autoimmune polyendocrine syndromes (APSs) are defined as multiple autoimmune-mediated endocrine gland failures. The current classification criteria of APSs propose four main presentations, based on clinical features. APS-1 is characterized by three main clinical conditions: chronic mucocutaneous candidiasis, chronic hypoparathyroidism and Addison’s disease (AD). APS-2 (or Schmidt syndrome) is a combination of AD, autoimmune thyroid disease (TAD) and/or type 1 diabetes. APS-3 is defined as an association between TAD and another systemic or organ-specific autoimmune disease. Because TAD is the most prevalent autoimmune condition in the general population, APS-3 is the most frequently observed autoimmune polyendocrine syndrome. APS-4 includes other combinations of the autoimmune disorders previously described, which cannot be allocated in other APS definitions. Most of the autoimmune endocrine diseases of APSs are characterized and preceded by the development of organ-specific autoantibodies, usually directed to antigens expressed by endocrine cells. Different authors have suggested a common pathogenesis, basing on a similar mononuclear leukocyte infiltration and the detection of organ-specific autoantibodies.