Multiple autoimmune syndrome.

The co-occurrence of autoimmune diseases has been epidemiologically studied and has aided in our understanding of autoimmunity. The combination of at least three autoimmune diseases in the same patient has defined as multiple autoimmune syndrome (MAS). About 25 percent of patients with autoimmune diseases have a tendency to develop additional autoimmune diseases. MAS is recognized with increasing frequency. Several associations have been proposed as a form of MAS. Multiple autoimmune syndrome can be classified into three groups according to the prevalence of their associations with one another: type 1, type 2 and type 3. Genetic, infectious, immunologic and psychological factors have all been implicated in the development of MAS. In MAS, patients often have at least one dermatological condition, usually vitiligo or alopecia areata. The pathogenesis of multiple autoimmune disorders is not known yet, perhaps environmental triggers and genetic susceptibility are involved. Abnormalities of both humoral and cell-mediated immunity have been described. However, as new perspectives develop on the pathogenesis and natural history of autoimmune diseases, a refinement in the methodology for the study of the co-occurrence of disease is warranted in order to maximize the information that one may realize from such studies. This paper presents some recent results of studies in light of current understanding of the natural history of autoimmune diseases.