Antimitochondrial antibodies are markers for primary biliary cirrhosis and probably reflect a specific defect in immunoregulation underlying this disease. Antimitochondrial antibodies and their primary biliary cirrhosis-specific subtypes were tested before and up to 6 years after orthotopic liver transplantation. Sera from 31 consecutive patients were tested, 15 patients had primary biliary cirrhosis and 16 non-primary biliary cirrhosis. Antimitochondrial antibodies were investigated under code by immunofluorescence, and primary biliary cirrhosis-specific subtypes were determined by radioimmunoassay (anti-p62, anti-p48) and complement fixation test (anti-M2, anti-M4, anti-M8). Before orthotopic liver transplantation, antimitochondrial antibodies were detected by immunofluorescence in 13 of 15 patients with primary biliary cirrhosis. Of these patients, 12 were positive for anti-p62 and 8 for anti-p48. Ten patients were positive for anti-M2, 4 patients for anti-M4 and 7 patients for anti-M8. Two primary biliary cirrhosis patients and all non-primary biliary cirrhosis patients were negative with all tests. One month after orthotopic liver transplantation, antimitochondrial antibodies titers declined or became negative by antimitochondrial antibodies immunofluorescence, 3 patients became negative by radioimmunoassay for anti-p62 and 1 for anti-p48. With complement fixation test, 4 patients became negative for anti-M2, 2 for anti-M4 and 4 for anti-M8. Antimitochondrial antibody titer reduction observed 1 month after orthotopic liver transplantation remained unchanged in most sera during the following years. A rise was observed in two patients after 4 and 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)