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Chronic hepatitis C
1Department of Medicine, Royal Free Hospital School of Medicine, University of London, United Kingdom.
Insights
Hepatitis C virus (HCV) infection is diagnosed with antibody tests, but transmission routes for many cases remain unclear. Treatment with interferon-alpha shows limited efficacy, with a 25% overall response rate.
Area of Science:
- Hepatology
- Virology
- Immunology
Background:
- Hepatitis C virus (HCV) was identified in 1989, leading to antibody tests (anti-HCV).
- HCV is linked to post-transfusion hepatitis, hepatocellular carcinoma, and chronic liver disease.
- Diagnosis historically relied on excluding other causes of non-A, non-B hepatitis.
Purpose of the Study:
- To review the current understanding of Hepatitis C virus (HCV) infection.
- To discuss diagnostic methods, transmission, and clinical manifestations of HCV.
- To evaluate treatment options and outcomes for chronic HCV infection.
Main Methods:
- Review of scientific literature on Hepatitis C virus (HCV).
- Analysis of diagnostic advancements, including antibody and RNA detection.
- Examination of epidemiological data and clinical case studies.
Main Results:
- Anti-HCV tests are widely available, with 0.5-1% prevalence in blood donors.
- Parenteral exposure (transfusion, drug abuse) is a primary transmission route; other routes remain uncertain.
- Acute HCV is often mild, chronic disease indolent but can lead to cirrhosis and cancer; interferon-alpha yields a 25% sustained response rate.
Conclusions:
- HCV diagnosis and understanding have advanced significantly since 1989.
- Clarifying HCV transmission and improving treatment efficacy are critical research areas.
- Distinguishing HCV from autoimmune hepatitis and managing complications like cancer are key clinical challenges.
Abstract:
Formerly the diagnosis of acute and chronic non-A, non-B hepatitis was made by the exclusion of other causes. However, in 1989 cloning of an antigenic component of the hepatitis C virus (HCV) was reported. This led to first- and second-generation tests for antibody to HCV (anti-HCV) in serum. HCV has been associated with acute and chronic posttransfusion and sporadic non-A, non-B hepatitis, and with hepatocellular carcinoma. Viral HCV RNA can be estimated with the polymerase chain reaction test, but this technically difficult test is not generally available. The entire viral genome has been sequenced. The envelope region shows considerable variation, and mutant HCV infections are being described already. There are geographic variations in the prevalence of anti-HCV, but usually about 0.5% to 1% of healthy blood donors test positive. Parenteral exposure to blood, especially by transfusion or drug abuse, remains a certain means of acquiring HCV infection. The method by which millions without parenteral risk factors acquire HCV remains uncertain. Vertical transmission and sexual and family spread occur only rarely. Body secretions are free of the virus. The mode of transmission may become clarified when tests for viral HCV as opposed to anti-HCV become generally available. Acute HCV infection usually is mild, and the chronic disease is also indolent. Carriers of hepatitis B virus or alcoholics who also test positive for HCV have more serious disease. Chronic HCV infection must be distinguished from autoimmune chronic active hepatitis. The most important difference is the response to corticosteroid therapy, which is good in autoimmune hepatitis and poor in HCV-related disease. Hepatocellular carcinoma can complicate HCV-related cirrhosis, usually about 20 years after infection with HCV. Recombinant interferon-alpha is used to treat chronic HCV disease, but selection of patients, dose, and duration of therapy are uncertain. In general, 50% of patients respond to the treatment, but 50% of these will have a relapse, with an overall response rate of 25%. Liver transplantation in patients with end-stage HCV disease usually is followed by infection of the graft.