BACKGROUND
Differentiation of viral hepatitis from acute cellular rejection (ACR) after liver transplantation can be difficult because of overlapping histological features. Here we investigated clinicopathologic characteristics of 311 liver allograft biopsies and searched for characteristic histopathological features that would facilitate the differential diagnosis between hepatitis B virus (HBV) infection and ACR. METHODS: A retrospective clinicopathologic examination of 311 liver allograft biopsies consisting of clinically proven ACR or HBV infection was performed. Immunohistochemical staining for HBcAg and HBsAg was done for 64 allograft biopsies showing HBV infection. RESULTS: Moderate to severe bile duct damage, diffuse centrilobular necrosis and centrilobular inflammation (p<0.000, for each) were more frequently observed in cases of ACR, whereas diffuse acidophilic bodies and spotty necrosis (p<0.000, for each) were more prevalent in cases of HBV infection. Immunopositivity for HBcAg (n=60, 93.8%) was higher than that for HBsAg (n=14, 21.9%) CONCLUSIONS: The presence of moderate to severe bile duct damage, diffuse centrilobular necrosis and centrilobular inflammation was a characteristic feature of ACR, whereas diffuse distribution of acidophilic bodies or spotty necrosis was the only characteristic feature of HBV infection. HBcAg was a more sensitive immunohistochemical marker than HBsAg for detecting HBV infection in liver allograft biopsies.