Comparison of histopathology in acute allograft rejection and recurrent hepatitis C infection after liver transplantation.

Recurrent hepatitis C infection after orthotopic liver transplantation (OLT) is frequent and may occur as early as a few weeks postoperatively. Early histopathological features of recurrent hepatitis C virus (HCV) infection may be modified by immunosuppressive therapy and can be difficult to differentiate from acute allograft rejection (AAR). Thus, we retrospectively compared histopathological features of liver biopsy specimens from two carefully selected patient groups: one with unequivocal recurrent hepatitis C, the other with unequivocal AAR. Index biopsy specimens obtained at the time of the appearance of liver test abnormalities after OLT and all serial liver biopsy specimens (2 to 13 per patient) were assessed under code and scored semiquantitatively for 44 histopathological variables. The index biopsy specimens from patients with recurrent HCV infection and AAR index biopsies (AAR-Ib) differed significantly (P < .05) for 11 features (10 features were statistically associated with AAR and 1 with early recurrence of HCV infection). Statistically significant features associated with AAR included bile duct injury with overlapping nuclei, lymphocytic infiltrates and necrosis, endothelialitis, portal inflammatory infiltrates containing eosinophils and polymorphonuclear leukocytes, hepatocyte mitoses, and zone 3 canalicular cholestasis. In contrast, the only statistically significant feature associated with early recurrent HCV was sinusoidal dilatation. Stepwise discriminant analysis showed that the presence of eosinophils in the portal inflammatory infiltrate, bile duct necrosis, and bile duct lymphocytic infiltrates were independently associated with AAR. However, serial biopsy specimens from patients with recurrent HCV infection showed statistically significant progression in scores for portal inflammation, portal lymphoid aggregates, and lobular inflammation. We conclude that (1) multiple histopathological features are associated with AAR; (2) early recurrent HCV infection is characterized by elevated alanine aminotransferase levels, positive HCV RNA by polymerase chain reaction (PCR), and absence of diagnostic histopathological features; and (3) serial biopsies are needed to demonstrate progression of histopathological features of recurrent hepatitis C.