English: Types of autoimmune diseases. There are two categories of autoimmune diseases: organ-specific autoimmune diseases and nonorgan specific autoimmune diseases, also called systemic diseases. Organ-specific autoimmune diseases are restricted to certain organs or a particular tissue. Nonorgan specific autoimmune diseases are characterized by extensive lesions that are secondary to an autoimmune reaction against ubiquitous autoantigens. There are also many overlap syndromes that may be characterized by the association of two or more organ-specific and systemic autoimmune diseases, due probably to the existence of common immunogenetic factors. Finally, such categorization of autoimmune diseases does not take into account diseases resulting from immune reactions against foreign antigens expressed in a target tissue, especially in viral diseases. It also ignores autoimmunity observed under physiological conditions in the absence of any pathological tissue damage. (The list of pathologies presented in this figure is not exhaustive.).