PCNA expression and electron microscopic study of acinus-forming hepatocytes in chronic hepatitis B

One of the major morphologic characteristics of hepatitis B is a hepatocellular regeneration which is induced by massive hepatocyte necrosis and associated with proliferative activity of hepatocytes. The purpose of this study is to document the proliferative activity of hepatocytes in various types of hepatitis B by immunohistochemical staining for proliferative cell nuclear antigen-labelling index (PCNA-LI) and electron microscopy.

We studied 83 patients with hepatitis B: 11 cases of acute viral hepatitis, 24 cases of mild chronic hepatitis, 34 cases of severe chronic hepatitis with early cirrhosis and 14 cases of severe chronic hepatitis. The PCNA was tested by immunohistochemical staining using anti-PCNA antibody. Furthermore we evaluated the ultrastructure of acinus-forming hepatocytes (AFH) by electron microscopy.

The expression rate and labelling index of PCNA were 27.3% and 5.3 +/- 0.9% in acute viral hepatitis, 62.5% and 22.9 +/- 31.7% in mild chronic hepatitis, and then 47.1% and 14.1 +/- 24.2% in severe chronic hepatitis with early cirrhosis, respectively (Figure 1). By contrast, no detectable PCNA expression was noted in AFH. Electron microscopic findings showed that hepatocytes forming a rosette underwent marked degenerative changes with sinusoidal capillarization and increased fine strands of collagen fiber in portal area.

The proliferative activity of hepatitis B was significantly decreased in severe chronic hepatitis containing AFH. This result suggested that differences in proliferative activity was associated with hepatic cell necrosis and AFH.