Hepatitis C virus: quantitation and distribution in liver

Area of Science:

• Hepatology
• Virology
• Molecular Biology

Background:

• Optimal methods for viral quantitation in chronic hepatitis C virus (HCV) infection are not established.
• Determining the most appropriate site for viral load assessment in HCV patients remains unclear.

Purpose of the Study:

• To develop and validate a sensitive, specific, and reproducible method for quantifying HCV RNA in liver tissue.
• To assess the representativeness of viral load measurements from liver biopsy samples.

Main Methods:

• Developed an efficient RNA extraction method from liver tissue (89% recovery).
• Employed branched DNA technology for accurate HCV RNA amplification, demonstrating strong concordance across multiple tests.
• Validated sensitivity (95%) and specificity (100%) of the assay.

Main Results:

• HCV RNA was detectable in as little as 2 mg of liver tissue.
• Viral load measurements from needle biopsies were representative of other liver sites (95% within 2.2-fold of geometric mean).
• Mean liver-to-serum HCV RNA ratio was 103 (range 17.4-286); hepatic levels were consistently higher than serum levels.

Conclusions:

• A reliable method for quantifying hepatic HCV RNA has been developed.
• Liver biopsy measurements accurately represent viral load across different liver sites.
• While hepatic HCV RNA is consistently higher than serum levels, the ratio is variable, and clinical utility requires further definition.