Hepatitis C virus infection. Biological and immunological features.
The recent cloning and genomic identification of hepatitis C virus (HCV) by sensitive and specific immune techniques has allowed a better definition of both histopathological and clinical features of the previously not well defined non-A, non-B hepatitis. In this regard, antibodies to different HCV antigens are usually found during infection, even if some of them such as anti-E1 and anti-E2/NS1 have been shown to be associated with significant viraemic levels. Acute hepatitis C is self-limiting in a minority of cases only. Over 60% of acute hepatitis becomes in fact chronic and may progress towards cirrhosis. In about 10% of cases, hepatocellular carcinoma may develop in cirrhotic livers. The occurrence of a strict relationship between immunoresponsiveness and disease activity is suggested by the observation that peripheral blood mononuclear cell (PBMC) proliferation induced by NS3 structure is associated with self-limiting acute hepatitis, while PBMC stimulation by core antigen characterizes chronic C hepatitis. The demonstration of lymphoid aggregates, bile duct lesions, intraportal lymphocyte infiltration, increased adhesion molecule expression and augmented cytokine release clearly emphasizes the involvement of immune-mediated reactions in the development of liver damage, even if a direct cytopathic effect cannot be excluded. Finally, it is likely that HCV may favour, through immune-mediated mechanisms, autoantibody generation and/or the appearance of some extrahepatic autoimmune manifestations during the course of HCV chronic infection.
Fiore
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G
Dipartimento di Clinica Medica, Immunologia e Malattie Infettive, Università, Bari.
Jirillo
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E
Schiraldi
O
O
Antonaci
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S
D000818:Animals; D000917:Antibody Formation; D015551:Autoimmunity; D002908:Chronic Disease; D016679:Genome, Viral; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology; D006526:Hepatitis C / Q000276:immunology* / Q000821:virology*; D006801:Humans; D007111:Immunity, Cellular