Morphological studies on the mechanism of hepatocellular injury during acute phase of infection in marmosets inoculated with hepatitis A virus.

The histological changes during the acute phase of infection in the livers of marmosets inoculated with hepatitis A virus were examined. The acute phase was divided into four stages according to the liver enzyme changes and serological markers for the viral infection (Stage I, II, III, IV). Round cell infiltration in the portal tracts was first recognized in Stage I. Localization of parenchymal changes was predominantly periportal in Stage I, II, and IV, whereas the lesion was diffuse in Stage III. Hepatitis A virus antigen (HAVA) was widely distributed but spotty and the largest amount of HAVA was found in Stage II by immunofluorescent and immunoperoxidase study. By electron microscopy the endoplasmic reticulum was altered in the liver cells and in some area there was interaction between the hepatocytes and lymphocytes. These findings suggest that hepatocellular damages seen in this model are the result of immune response rather than cytotoxic effect.