Hepatitis E virus (HEV) infection induces self-limiting liver disease in immunocompetent individuals. Cases of chronic hepatitis E have recently been identified in organ transplant recipients. We questioned if chronic hepatitis E plays a role in graft hepatitis after liver transplantation in a low endemic area. Two hundred twenty-six liver transplant recipients, 129 nontransplanted patients with chronic liver disease, and 108 healthy controls were tested for HEV antibodies. HEV RNA was investigated in all sera from transplanted patients. HEV antibodies were detected in 1 healthy control (1%), 4 patients with chronic liver disease (3%), and 10 liver transplant recipients (4%). Three liver transplant patients also tested positive for HEV RNA. Two of them developed persistent viremia with HEV genotype 3. The patients were anti-HEV immunoglobulin G-negative and HEV RNA-negative before transplantation and had an episode of acute hepatitis 5 or 7 months after transplantation, which led to advanced liver fibrosis after 22 months in 1 patient. Seroconversion to anti-HEV occurred not before 4 months after the first detection of HEV RNA. The possibility of reverse zoonotic transmission was experimentally confirmed by the infection of 5 pigs with a patient's serum. The pigs showed histological inflammation in the liver, and HEV RNA was detectable in different organs, including muscle. In conclusion, the prevalence of HEV infection in Central European liver transplant recipients is low; however, chronic hepatitis E may occur and needs to be considered in the differential diagnosis of graft hepatitis. The diagnosis of HEV infection should be based on HEV RNA determination in immunosuppressed patients. We suggest that immunocompromised individuals should avoid eating uncooked meat and contact with possibly HEV-infected animals. Liver Transpl 16:74-82, 2010. © Infection with hepatitis E virus (HEV) usually results in acute, self-limiting hepatitis in immunocompetent individuals. 1 Acute hepatitis E may rarely progress to fulminant hepatic failure, which more often occurs in pregnant women 2 and patients with alcoholism and chronic liver diseases. 3 HEV is a single-stranded, non-

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The envelope of bovine viral diarrhea virus (BVDV) contains the glycoproteins E rns , E1 and E2. Complementation of a recombinant vesicular stomatitis virus (VSV) with BVDV glycoproteins resulted in infectious pseudotyped viruses. To elucidate the specific role of each of the single envelope glycoproteins during viral entry, pseudotypes were generated bearing the BVDV envelope proteins in different combinations. Pseudoviruses that contained E1 and E2 but not E rns were infectious, indicating that E rns is dispensable for virus entry. VSV/BVDV pseudotypes with chimeric proteins (the ectodomain of the BVDV glycoprotein and the transmembrane domain of the VSV-G protein) were not infectious. The fact that E1-E2 heterodimers were not detected if one of the proteins was chimeric indicated that the heterodimers are crucial for BVDV entry. It was shown by site-directed mutagenesis that the charged amino acids in the transmembrane domains of BVDV E1 (lysine and arginine) and the charged amino acid in the transmembrane domain of E2 (arginine) play a key role in heterodimer formation. Pseudoviruses bearing the mutation E2-R/A, where the charged amino acid was substituted by alanine, were not infectious, supporting the hypothesis that E1-E2 heterodimers are essential for BVDV entry.

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21Hepatitis E virus is the causative agent of an acute hepatitis in humans. In 22 industrialized countries, autochthonous hepatitis E cases in the past were mainly of 23