[Molecular mimicry in the etiology of autoimmune diseases].

 There are currently more than 80 different autoimmune diseases, affecting approximately 100 million people worldwide. The etiology of most autoimmune diseases is unknown. The highest incidence of these diseases is in the developed countries and they are more common in women than in men. Among the most often listed factors responsible for the onset of autoimmunity are genetic predisposition and the phenomenon known as molecular mimicry. The latter stems from a similarity between microbial antigens and antigens present in the human body (self antigens). It is believed that such homology is responsible for the production of auto-antibodies and in consequence attack of the immune system against host tissues and organs. However, the main molecular factors responsible for these diseases in most cases remain unknown. While pathogenesis of many autoimmune diseases indicates the presence of molecular mimicry, at the same time the similarities between the own and foreign structures do not always result in autoimmunity. Therefore, prediction of such crucial homology responsible for the development of autoimmune disease is extremely difficult. In this paper we present examples of autoimmune diseases such as type 1 diabetes, multiple sclerosis, reactive arthritis and the potential contribution of micro-organisms to the mechanism of molecular mimicry.