Introductory Chapter: Autoantibodies and Their Types

Autoantibodies are groups of antibodies that are directed against body’s own antigen. These autoantibodies are generated against different types of antigens in various autoimmune diseases. Clinical symptoms of systemic autoimmune diseases are characterized by the involvement of various organs in addition to the production of non-organ specific autoantibodies. These autoantibodies in autoimmune diseases are associated with a specific clinical symptom within a spectrum [1]. Most of the autoantibodies have diagnostic and prognostic importance with respect to their associated disease and all of these are not involve in the pathogenesis of these diseases. Most autoantibodies are mainly used as biological markers for certain disease but they do not actually reflect the pathophysiological process underwent during the course of the disease, however, many autoantibodies also have a pathogenetic roles such as antinuclear antibodies and anti-tTG antibodies in celiac disease. For example, autoimmune hepatitis is a chronic disease which is characterized by various clinical, histological as well as immunological characteristics including production of circulating autoantibodies and high serum concentration of gamma globulin [2]. These autoantibodies are very important for the correct diagnosis and classification of autoimmune liver disease [3] and they are not related with the pathogenesis of autoimmune hepatitis. However, some of the systemic autoimmune disease relating these autoantibodies in the sense that their levels are changes during the course of the disease. These include anti-double stranded DNA antibodies in systemic lupus erythematosus (SLE) and anti-neutrophil cytoplasmic autoantibodies in the vasculitis [4]. Other types of antibodies like anti-nucleosome and anti-CIq autoantibodies can function as both markers of the disease activity as well as pathogenic autoantibodies in SLE [5, 6].