Anti-nuclear antibodies, also known as anti-nucleic acid antigen antibodies, are a group of autoantibodies against complexes of DNA, RNA, proteins and molecules of these substances in the nucleus of cells, and each anti-nuclear antibody can be distinguished according to the properties of each molecule in its nucleus. I. Anti-DNA antibodies. II. Anti-histone antibodies. Anti-nonhistone antibodies. Anti-nucleolus antibodies, etc. Each major category is further divided into many types depending on the antigenicity. Therefore, antinuclear antibodies are, in a broad sense, a group of autoantibodies of various clinical significance. Antinuclear antibodies are mainly found in IgG, but also in IgM, IgA, and even IgD and LgE. Antinuclear antibodies recognize a variety of cells and components and can be specifically found in many autoimmune diseases, especially rheumatic diseases. It can determine disease activity and prognosis, observe treatment response, and guide clinical treatment.