Hepatitis C virus-specific B cell activation: IgG and IgM detection in acute and chronic hepatitis C

Background/Aims/Methods: Immunological responses to hepatitis C virus infection have not been fully studied. In an attempt to clarify some immunopathogenetic aspects of B cell activation during acute and chronic hepatitis C virus infection and to identify markers of chronicity or of recovery, the humoral response in hepatitis C virus-infected patients was studied. Results: In children with acute jaundice, with negative markers of acute hepatitis A, B and E, six of 87 (6,9%) had detectable anti-HCV IgM, and only one (1.1%) had detectable anti-HCV IgG. In adults with acute jaundice, with negative markers of acute hepatitis A, B and E, ten of 23 (43.5%) had detectable anti-HCV IgM associated in eight patients with detectable anti-HCV IgG. In chronic hepatitis C virus-infected adult patients, all anti-HCV IgG seropositive, four of 14 (28%) patients had detectable HCV-IgM in serum. In vitro specific antibody production was inducible in a minority of patients. In acute and chronic hepatitis C virus-infection, IgM-HCV serology did not correlate with viremia as detected by polymerase chain reaction. Conclusions: Therefore, the polymerase chain reaction remains at the moment the only direct marker to demonstrate hepatitis C virus viral replication in patients with acute and chronic hepatitis while anti-HCV IgM analysis alone has only a limited diagnostic value in hepatitis C virus-infection.