In patients with autoimmune (AI) diseases autoantibodies (Abs) directed to polysaccharides, nucleic acids, proteins, peptides, nucleoprotein complexes, and enzymes with different catalytic functions may be induced spontaneously by primary antigens and can have characteristics of the primary antigen, including the catalytic activity of idiotypic and/or antiidiotypic Abs. The discovery of IgG specifically hydrolyzing intestinal vasoactive peptide in the sera of asthma patients (Paul S., 1989) stimulated of the studies of natural catalytic antibodies (abzymes). Detection of abzymes (Abzs) was shown to be the earliest indicator of development of different autoimmune diseases (АD). At the early stages of ADs, the repertoire of Abzs is usually relatively small but it greatly increases with the progress of the disease, leading to the generation of catalytically diverse abzymes with different activities and functions. Some Abzs are cytotoxic and can play an important negative role in the pathogenesis of AI pathologies, while positive roles have been proposed for other abzymes.