Hepatitis C: current options for nonresponders to peginterferon and ribavirin

The application and mechanism of action of ribavirin in therapy of hepatitis C

Ribavirin has been used as an antiviral agent for several decades. Although it has activity against numerous viruses, its major use clinically has been in the treatment of respiratory syncytial virus in paediatric patients and chronic HCV infection in both children and adults. This review highlights the clinical application and mechanism of action of ribavirin and discusses the future role of ribavirin in treatment of HCV where there are intense research efforts to improve therapy.

Unexpected maintenance of hepatitis C viral diversity following liver transplantation

Chronic hepatitis C virus (HCV) infection can lead to liver cirrhosis in up to 20% of individuals, often requiring liver transplantation. Although the new liver is known to be rapidly reinfected, the dynamics and source of the reinfecting virus(es) are unclear, resulting in some confusion concerning the relationship between clinical outcome and viral characteristics. To clarify the dynamics of liver reinfection, longitudinal serum viral samples from 10 transplant patients were studied. Part of the E1/E2 region was sequenced, and advanced phylogenetic analysis methods were used in a multiparameter analysis to determine the history and ancestry of reinfecting lineages. Our results demonstrated the complexity of HCV evolutionary dynamics after liver transplantation, in which a large diverse population of viruses is transmitted and maintained for months to years. As many as 30 independent lineages in a single patient were found to reinfect the new liver. Several later posttransplant lineages were more closely related to older pretransplant viruses than to viruses detected immediately after transplantation. Although our data are consistent with a number of interpretations, the persistence of high viral genetic variation over long periods of time requires an active mechanism. We discuss possible scenarios, including frequency-dependent selection or variation in selective pressure among viral subpopulations, i.e., the population structure. The latter hypothesis, if correct, could have relevance to the success of newer direct-acting antiviral therapies.

[Prophylaxis and treatment of chronic viral hepatitis as the prevention of hepatocellular carcinoma]

As hepatitis B and C virus (HBV, HCV) play a pivotal role in the development of hepatocellular carcinoma (HCC), the prophylaxis and treatment of these infections may mean also the prevention of HCC. The primary prevention of HCC is vaccination against HBV as well as the screening of blood donors for HBV and HCV markers. The means of secondary HCC prevention are as follows: antiviral therapy of HBV and HCV-related hepatitis and cirrhosis, screening ("surveillance") of cirrhotic patients for HCC using alpha-fetoprotein and ultrasound, and adjuvant antiviral treatment of HCC patients following curative tumor resection/ablation. It may be anticipated that the world-wide spread of HBV vaccination, the more effective individual treatment and novel antivirals will lead to the decrease of HCC incidence in the not so distant future.