Clonal proliferation of hepatocytes and progression of liver disease in chronic hepatitis B virus infection [ 2007 - 2009 ]

Research Grant

Researchers: A/Pr Allison Jilbert (Principal investigator) ,  A/Pr Hugh Harley ,  E/Pr William Mason

Brief description Infection with the hepatitis B virus (HBV) can lead to either acute resolving, or chronic HBV infection. Chronic HBV infections are often associated with severe liver disease, and increased risk of liver cancer and occur worldwide in 350 million people. HBV infects hepatocytes, the major cell of the liver. Early during infection 100% of hepatocytes are infected. However, this percentage declines over time to 10-50% or less. The reasons for this are unknown. We suggest that changes in the liver cell population occur because of the immune response against infected hepatocytes. We hypothesize that the immune response kills infected hepatocytes and provides and growth advantage to hepatocytes that can no longer be infected with HBV. This leads to the clonal proliferation of HBV-negative hepatocytes that over time become the major cell population in the liver. We will study human liver tissue using molecular techniques to detect the HBV DNA that integrates randomly into cell DNA during HBV infection. We will then determine the copy number of specific integrated virus-cell junctions as a measure of hepatocyte proliferation. Sections of fixed liver will also be examined for changes in histology and frequency of HBV infection. These studies will determine if foci of HBV-negative hepatocytes are clonal. This finding would suggest that a major role of the immune system in the development of liver cancer is to restrict the genetic pool of hepatocytes. We hypothesise that liver cancer beings with a very specific survival advantage for hepatocytes that lack HBV replication and antigen expression, and that proliferation of these cells expands the pool of potentially altered HCC precursor cells.

Funding Amount $AUD 420,558.42

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant