Anti-smooth muscle antibody

Anti-smooth muscle antibody (SMA) is an autoantibody with the body's smooth muscle tissue as the antigen. It has no organ and species specificity and is mainly of the IgG and IgM types. Tissues such as rat liver, kidney, human thyroid and platelets share common antigenicity with smooth muscle actin. Therefore, using purified sarcoplasmin as an antigen, SMA can be detected by precipitation test, indirect hemagglutination test, radioimmunoassay and enzyme immunoassay. But the most commonly used indirect immunofluorescence method is to use smooth muscle as the antigen sheet.