Infections and autoimmune endocrine disease.

The literature examined in this review points to the possible involvement of infectious agents in the pathogenesis of autoimmune endocrine diseases, primarily autoimmune thyroid disease and diabetes mellitus. Various mechanisms have been proposed to explain induction of autoimmunity by infection but it seems that three possibilities may be important in individuals susceptible to developing autoimmune disease: molecular mimicry (perhaps to retroviruses); polyclonal T cell activation (by an endogenous superantigen or an infecting organism); and MHC class II antigen induction. It seems reasonable that all three mechanisms operate together or separately in different individuals. Data continue to accumulate in favour of infectious agents being important initiators of autoimmune disease.