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Hepatitis C virus infection and disease. Diagnostic problems
F Bonino1, M R Brunetto, F Negro
1Division of Gastroenterology, Molinette Hospital, Turin, Italy.
Insights
Hepatitis C virus (HCV) causes chronic liver disease, including cirrhosis and cancer. Diagnosis relies on detecting anti-HCV antibodies and HCV-RNA, but specific markers for HCV-induced liver disease are still needed.
Area of Science:
- Virology
- Hepatology
- Immunology
Background:
- Hepatitis C virus (HCV) is a lipid-enveloped RNA virus causing chronic infections in 40-60% of individuals.
- Chronic HCV infection is linked to liver diseases, including cirrhosis and hepatocellular carcinoma.
- The physical structure of HCV remains largely unknown, hindering a complete understanding of its pathogenesis.
Purpose of the Study:
- To review the diagnostic approaches for Hepatitis C virus infection.
- To evaluate the utility of antibody detection and RNA quantification in diagnosing and monitoring HCV.
- To discuss the limitations in current diagnostic markers for HCV-induced liver disease.
Main Methods:
- Review of diagnostic methods including anti-HCV antibody detection and HCV-RNA quantification.
- Analysis of serological markers like anti-C-22 and anti-C-100 for monitoring treatment response.
- Discussion of limitations of current diagnostic assays, such as distinguishing past from present infections.
Main Results:
- Second-generation assays achieve ~95% diagnostic sensitivity for HCV.
- HCV-RNA detection by RT-PCR is a valid alternative for anti-HCV negative infections and early acute hepatitis.
- Anti-C-100 is an early disappearing antibody in responders and associated with liver disease, suggesting it as an indirect marker.
Conclusions:
- Current diagnostic tools for HCV infection have improved but do not fully distinguish past from present infections.
- Monitoring anti-HCV titres and HCV-RNA levels are crucial for managing interferon therapy.
- There is an ongoing need for specific markers to accurately assess HCV-induced liver disease.
Abstract:
Hepatitis C virus (HCV) is a lipid-enveloped single-stranded RNA virus with an unknown physical structure as only putative HCV particles have been identified by electron microscopy. Although HCV lacks the retroviral properties of being able to integrate into host DNA, it causes chronic infection in a considerable number of infected individuals (40-60%). Chronic infection is associated with a wide spectrum of liver diseases ranging from normal presentation to the different forms of chronic hepatitis, cirrhosis (about 20% of cases) and hepatocellular carcinoma. HCV therefore is not invariably and equally pathogenic, and genetic heterogeneity could be a major cause of such variability. Diagnosis of HCV infection relies on anti-HCV and HCV-RNA detection. Using second-generation assays, diagnostic sensitivity has increased to about 95%, but detection of anti-HCV does distinguish past from present infections. Only rising anti-HCV titres or anti-HCV seroconversion confirm a recent HCV infection. In anti-HCV-negative infections and cases of early acute hepatitis, HCV-RNA detection by RT-PCR represents a valid diagnostic alternative. In patients undergoing interferon therapy, testing for anti-HCV by immunoblotting represents a valid routine tool to monitor response. Anti-C-22 has the highest titre and persists longer while anti-C-100 is the earliest antibody to disappear in responders. The significant association between serum anti-C-100, HCV-RNA and liver disease suggests that anti-C-100 is an indirect marker of hepatitis C, but true markers of HCV-induced liver disease are still lacking.