Viral kinetics of the Hepatitis C virus

Hepatitis A virus and hepatitis B virus were identified as the cause of infectious hepatitis and serum hepatitis respectively in the beginning of the seventies. After introduction of screening tests for hepatitis A and B 4 only 25% of the cases of post transfusion hepatitis were found to be caused by hepatitis B and none by hepatitis A. One or more viruses other than hepatitis A or B were suspected to be the cause of the remaining 75% of post-transfusion hepatitis. Initially, this hepatitis was named non-A, non-B hepatitis. After the discovery in 1989 of the hepatitis C virus (HCV), HCV was found to explain the large majority of post transfusion hepatitis 5,6. HCV is an enveloped, s'mgle-stranded RNA virus, approximately 50 nm in diameter, that has been classified as a separate genus in the Flaviviridae family J Occasionally acute viral hepatitis with jaundice occurs, but usually HCV presents as chronic hepatitis. In fact it appeared to be the most important causes of chronic viral hepatitis in Europe and the United States

Changes in anti-viral effectiveness of interferon after dose reduction in chronic hepatitis C patients: a case control study

BACKGROUND: High dose interferon induction treatment of hepatitis C viral infection blocks viral production over 95%. Since dose reduction is often performed due to clinical considerations, the effect of dose reduction on hepatitis C virus kinetics was studied. METHODS: A new model that allowed longitudinal changes in the parameters of viral dynamics was used in a group of genotype-1 patients (N = 15) with dose reduction from 10 to 3 million units of interferon daily in combination with ribavirin, in comparison to a control group (N = 9) with no dose reduction. RESULTS: Dose reduction gave rise to a complex viral kinetic pattern, which could be only explained by a decrease in interferon effectiveness in blocking virion production. The benefit of the rapid initial viral decline following the high induction dose is lost after dose reduction. In addition, in some patients also the second phase viral decline slope, which is highly predictive of success of treatment, was impaired by the dose reduction resulting in smaller percentage of viral clearance in the dose reduction group. CONCLUSIONS: These findings, while explaining the failure of many induction schedules, suggest that for genotype-1 patients induction therapy should be continued till HCVRNA negativity in serum in order to increase the sustained response rate for chronic hepatitis C