Inhibition of the adenine nucleotide translocator by organ specific autoantibodies in primary biliary cirrhosis.

Sera from 13 patients with proven primary biliary cirrhosis (PBC) were studied for the capacity to bind to the adenine nucleotide translocator (ANT) isolated from heart, kidney and liver mitochondria. Antibodies against the ANT from liver were detected in the serum of all PBC patients, while 10 of 13 sera were negative when tested with the ANT from heart. None of the sera showed a significant binding to the ANT from kidney. The specific binding and the organ specificity of the autoantibodies against the ANT from liver were also confirmed by immunoabsorption studies on the isolated proteins. To distinguish between antibody titre and antibody activity, we measured the ability of the antisera to inhibit the adenine nucleotide transport across inner mitochondrial membrane using isolated mitochondria from heart, kidney and liver. Six of 13 patient sera tested inhibited the adenine nucleotide transport from liver mitochondria, however, none of the sera inhibited the transport from heart or kidney mitochondria again indicating the organ specificity of the antigen and the autoantibodies.