[Subclasses of antibodies to hepatitis B core antigen in chronic HBV infections: changes during treatment with interferons and predictors of response].

Response to interferon therapy in chronic hepatitis B virus (HBV) carrier is preceded by the appearance of IgM class anti-HBc (antibody to hepatitis B core antigen). The temporal relationship and magnitude of the IgM anti-HBc response is variable, suggesting that the antibody is not directly involved in hepatocyte lysis, but is merely a marker of a changed state of immunity to the nucleocapsid proteins induced by interferon. IgG 1, 2, 3 and 4 did not change during therapy. IgG anti-HBc of all subclasses was absent in two Chinese HBV carriers. Lower than normal titres of anti-HBc (P less than 0.001) were detected in human immunodeficiency virus antibody positive (anti-HIV) carriers. These data indicate the presence of altered immunity to the nucleocapsid antigens in these two types of chronic HBV carrier that are known to respond poorly to antiviral therapy.