Clinical Virology of Hepatitis C (Molecular Virology Core Laboratory)

David Gretch, MD, PhD

The Clinical Virology of Hepatitis C research project is a sub-project of "Experimental Models and Clinical Virology of Hepatitis C" (U19-NIAID, PI-Nelson Fausto, MD-UW). The major objective of this project is to describe both the clinical and molecular virology of HCV infection in a cohort of Alaskan Natives. It has been difficult to establish correlations between the mutational variability of HCV and the clinical and pathologic course of chronic hepatitis because the natural history of the disease is prolonged. This study is working to define the longitudinal relationship between HCV replication and liver disease outcome in a extended cohort study. The aims of this study are to:

1. Determine if the longitudinal patterns of HCV viremia are predictive of the long term outcome of chronic infection with HCV. The investigators have already developed a highly accurate quantitative competitive (QC) polymerase chain reaction (PCR) assay for determining the absolute level of HCV RNA in clinical specimens. This method will be used to characterize patterns of HCV viremia over a 5 to 20 year period in patients with chronic hepatitis C.
2. Determine if specific mutations that develop in the HCV genome over time correlate with the clinical and histopathologic outcome of chronic hepatitis C infection. HCV genomes from patients with severe liver disease are compared to HCV genomes from patients with mild liver disease to determine if large deletions or insertions occur within the viral genome. Patients with severe liver disease are also matched with patients with mild liver disease (genotype matched) to determine if HCV quasispecies diversity changes over time.

The investigators have begun the characterization of the distribution of HCV genotypes in the Alaskan Native cohort and shown an emergence of HCV genotype 1a infection in this population. The investigators have developed methods and optimized the experimental conditions for characterization of HCV quasispecies. A molecular assay for analyzing the HCV E1 gene for confirmation of HCV genotypes has been optimized and techniques for resolution of mixed HCV infections have been developed.

The Molecular Virology Core Laboratory functions as the Core Laboratory for the project "Experimental Models and Clinical Virology of Hepatitis C" . The general objectives of the parent projects are to develop tissue culture and animal model systems to study questions of HCV pathogenesis and therapeutics, and to use in these studies well-characterized virus isolates from the cohort of Alaskan Natives. The Core Laboratory is responsible for providing well-characterized HCV isolates and quasispecies from human samples for studies in liver cell cultures and in transgenic mice. The Core Laboratory also characterizes HCV replication and tracks HCV quasispecies variants in cell culture systems and animal models.

Report courtesy of Anna Marie Beckmann

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Recent Publications

Thomassen, L., Chung, M., Wilson, J. and Gretch, D. Resolution of mixed HCV infections by heteroduplex gel shift analysis. (Abstract, AASLD). (1996).

Hofgartner, W.T., Polyak, S.J., Sullivan, D.G. and Gretch, D.R. Mutations in the NS5A gene of hepatitis C virus in North American patients infected with HCV genotype 1a. (Abstract, ACLPS) (1997).