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Antimitochondrial antibodies in patients with chronic hepatitis C
S Grimbert1, C Johanet, F Bendjaballah
1Service d'Hépato-Gastroenterologie, Hôpital Jean Verdier, Bondy, France.
Insights
Antimitochondrial antibodies were detected in 1.5% of chronic hepatitis C patients. Their presence may link to the virus and disappear upon successful treatment, suggesting a potential role in hepatitis C virus (HCV) infection.
Area of Science:
- Hepatology
- Immunology
- Virology
Background:
- Autoantibodies are common in chronic hepatitis C virus (HCV) infection.
- The presence of antimitochondrial antibodies (AMAs) in HCV patients was previously unconfirmed.
- Primary biliary cirrhosis (PBC) is characterized by AMAs targeting the pyruvate dehydrogenase complex.
Purpose of the Study:
- To investigate the prevalence and characteristics of AMAs in untreated chronic hepatitis C patients.
- To determine the association between AMAs and HCV infection, and their response to interferon-alpha therapy.
Main Methods:
- Sera from 460 untreated chronic hepatitis C patients were tested for AMAs using indirect immunofluorescence.
- Positive AMA samples (titer > 1:50) were further analyzed by Western blot to identify recognized epitopes.
- Seven patients with positive AMAs were treated with interferon-alpha for six months.
Main Results:
- Seven out of 460 patients (1.5%) tested positive for AMAs; none had PBC.
- AMAs recognized oxo-dehydrogenase complex epitopes in three patients.
- One patient achieved HCV-RNA clearance and became AMA-negative after treatment; others showed sustained AMA positivity regardless of treatment response.
Conclusions:
- AMAs in chronic hepatitis C may target different epitopes than those in PBC.
- AMA production appears linked to the presence of HCV and may resolve upon viral eradication.
- AMA positivity does not seem to alter the clinical course or interferon-alpha treatment response in chronic hepatitis C.
Abstract:
Although autoantibodies have been found in the serum of patients with chronic hepatitis C virus (HCV) there has been no convincing evidence of the presence of antimitochondrial antibodies, until now. Sera from 460 untreated patients with chronic hepatitis C were tested for antimitochondrial antibodies, using an indirect immunofluorescence technique; and if they tested positive for the antibodies (titer more than 1:50), they also were treated by Western blot analysis. Seven (1.5%) sera were positive. None of the patients had biological or histological evidence of primary biliary cirrhosis. Antimitochondrial antibodies recognized one of the oxo-dehydrogenase multienzyme complexe's epitopes by Western blot assay in three patients only. All seven patients were then treated by interferon alpha for six months. None showed exacerbation of liver disease during treatment. HCV-RNA disappeared from the serum in one patient who became negative for anti-M2 antibodies. The four patients who did not respond to interferon-alpha therapy, and the two who relapsed after treatment withdrawal, had sustained positive antimitochondrial antibodies. These data suggest that: 1) antimitochondrial antibodies present in patients with chronic hepatitis C do not always recognize the same epitopes as in primary biliary cirrhosis; 2) these antibodies may disappear after eradication of HCV, suggesting that the production of antimitochondrial antibodies is linked to the presence of the virus and 3) the clinical and biological course of chronic hepatitis C, and the response to interferon-alpha therapy, does not seem to be different in patients who are positive for antimitochondrial antibodies.