Autoimmune diseases(ADs)are due to the lack of autoantigen immune tolerance and they are chronic and heterogeneous conditions that affect specific target organs or multiple organ systems. Polyautoimmunity(PA)is defined as the presence of more than one AD in a single patient. It provides a major clinical evidence for autoimmune tautology and emphasizes that different immune phenotypes can coexist in the same individual(i.e., individual carries a unique genotype). When three or more ADs coexist, this condition is called multiple autoimmune syndrome(MAS). This article will make a summary about the pathogenesis of autoimmune diseases and PA and MAS in several common clinical autoimmune diseases in order to help clinical work and further research.

Autoimmune disease; Polyautoimmunity; Multiple autoimmune syndrome; Pathogenesis