Sjogren's syndrome and primary biliary cirrhosis: Presence of autoantibodies to purified mitochondrial 2-OXO acid dehydrogenases

Sjogren's syndrome is well known for the presence of antibodies directed at specific nuclear antigens. However, the presence of antibodies reacting with a variety of other self antigens, including antimitochondrial antibodies, has often been reported although their significance is unknown. Moreover, patients with Sjogren's syndrome have been occasionally reported to be concordant with primary biliary cirrhosis. To address this issue we studied in a group of 96 patients with Sjogren's syndrome the presence of autoantibodies to the dihydrolipoamide acetyltransferases of both pyruvate dehydrogenase and branch chain ketoacid dehydrogenase and to α-ketoglutarate dehydrogenase; these latter enzymes are the mitochondrial target antigens of primary biliary cirrhosis. We report that 7 of the 96 patients reacted with the mitochondrial antigens that are prominent in primary biliary cirrhosis. Moreover, in those patients showing reactivity with mitoch