Demonstration of antibody for glutamic pyruvic transaminase (GPT) in chronic hepatic disorders

The present paper describes the detection of an autoantibody for glutamic pyruvic transaminase (GPT) in sera of patients with chronic hepatic disorders. In 16 out of 500 patients, the existence of an antibody for pig GPT was demonstrated by the double antibody method, gel filtration and radioimmunoelectrophoresis. The antibody was demonstrated as an immunoglobulin G (IgG) with either polyclonal or monoclonal type (kappa or lambda). The binding portion of IgG with GPT was determined as the fragment Fab, but not Fc of IgG. Because the binding of 125I-pig GPT with the patient's antibody was displaced by human GPT, this antibody may have the characteristic of cross reacting with both pig and human GPT. Although the mechanism of production of the antibody for GPT and the pathological significance of the antibody in chronic hepatic disorders remained obscure, possible inhibition of GPT activity in serum is suggested in the presence of this antibody.