Hepatitis D virus: an update

Liver International
Early View (Articles online in advance of print)

Stéphanie Pascarella 1, Francesco Negro 2,3

Article first published online: 28 SEP 2010
DOI: 10.1111/j.1478-3231.2010.02320.x
© 2010 John Wiley & Sons A/S

1 Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
2 Division of Clinical Pathology, University Hospital, Geneva, Switzerland
3 Division of Gastroenterology and Hepatology, University Hospital, Geneva, Switzerland

*Correspondence: Correspondence Prof Francesco Negro, Divisions of Clinical Pathology and of Gastroenterology and Hepatology, University Hospital, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva 14, Switzerland Tel: +41 22 3795 800 Fax: +41 22 3729 366 e-mail: francesco.negro@hcuge.ch

Keywords:
cirrhosis;delta hepatitis;fulminant hepatitis;hepatitis D virus
 
Abstract

Hepatitis D virus (HDV) infection involves a distinct subgroup of individuals simultaneously infected with the hepatitis B virus (HBV) and characterized by an often severe chronic liver disease. HDV is a defective RNA agent needing the presence of HBV for its life cycle. HDV is present worldwide, but the distribution pattern is not uniform. Different strains are classified into eight genotypes represented in specific regions and associated with peculiar disease outcome. Two major specific patterns of infection can occur, i.e. co-infection with HDV and HBV or HDV superinfection of a chronic HBV carrier. Co-infection often leads to eradication of both agents, whereas superinfection mostly evolves to HDV chronicity. HDV-associated chronic liver disease (chronic hepatitis D) is characterized by necro-inflammation and relentless deposition of fibrosis, which may, over decades, result in the development of cirrhosis. HDV has a single-stranded, circular RNA genome. The virion is composed of an envelope, provided by the helper HBV and surrounding the RNA genome and the HDV antigen (HDAg). Replication occurs in the hepatocyte nucleus using cellular polymerases and via a rolling circle process, during which the RNA genome is copied into a full-length, complementary RNA. HDV infection can be diagnosed by the presence of antibodies directed against HDAg (anti-HD) and HDV RNA in serum. Treatment involves the administration of pegylated interferon-α and is effective in only about 20% of patients. Liver transplantation is indicated in case of liver failure.

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