The histology of acute autochthonous hepatitis E virus infection

Aim: To document the histological appearances of liver biopsies in autochthonous hepatitis E virus (HEV) infection. Methods and results: Four patients were serologically positive for HEV; three had no traditional risk factors, the fourth had recently returned from China. All four consumed meat products. Liver histology of the three autochthonous (locally acquired) cases showed portal tracts expanded by a severe mixed polymorph and lymphocytic inflammatory infiltrate, with a geographical distribution of polymorphs at the interface and lymphocytes centrally. Moderate to severe interface hepatitis and cholangiolitis were present. There was a striking acinar mixed inflammatory infiltrate made up of polymorphs, lymphocytes and macrophages; frequent apoptotic hepatocytes, focal necrosis, cholestatic rosettes and zone 3 canalicular and cytoplasmic bilirubinostasis were noted. Significant steatosis, megamitochondria and Mallory bodies were not present. There was no evidence of iron, copper or alpha(1)-antitrypsin accumulation. By contrast, the histology of the imported case of HEV infection showed less intense portal and acinar inflammation, no cholangiolitis and no geographical distribution of the portal inflammatory infiltrate. Conclusion: The histological appearances of autochthonous HEV infection are sufficiently distinctive to consider the diagnosis in an acute setting and possibly to differentiate it from the endemic form of the disease.