Hepatic distribution of E2 component of pyruvate dehydrogenase complex after transplantation

We have examined the distribution of the E2 component of pyruvate dehydrogenase complex in the liver of patients with native primary biliary cirrhosis (PBC), and after transplantation, using affinity-purified anti-E2 antibodies. In the posttransplantation group, we studied biopsy specimens from patients grafted for conditions other than PBC (n = 6) and those grafted for PBC with (n = 6) and without (n = 5) histological features suggestive of PBC recurrence. Features suggestive of PBC recurrence included portal tract granulomas, bile duct damage, ductopenia, and lymphoid aggregates. In the native liver from patients with PBC, there was increased staining of E2 on the biliary epithelial cells compared with hepatocytes, as previously described. However, in liver biopsy specimens from patients after transplantation, the pattern of staining of E2 was similar to that of normal, control liver in all three groups studied. These findings suggest that E2 overexpression on bile duct cells may not be important in the perpetuation of the bile duct damage in PCB, that expression in the allograft may be modified by immunosuppression, or that PBC does not recur in the allograft.