Relationship between membrane-bound immunoglobulin and viral antigens in liver cells from patients with hepatitis B virus infection

Abstract In an attempt to define further the significance of immunoglobulin G (IgG) fixed in vivo to the hepatocyte membrane in hepatitis B virus (HBV) infection, we have studied the relationship between presence of membrane-bound IgG and that of intracellular hepatitis B surface (HBsAg) and core (HBcAg) antigens in hepatocytes from 25 HBsAg chronic carriers. For this purpose, we have used a double immuno-fluorescence technique that is able to detect IgG and viral antigens within the same liver cell. In 15 patients with HBsAg-positive chronic active hepatitis, we found a statistically significant association between detection of membrane-bound IgG and that of intranuclear HBcAg within the same liver cells. On the contrary HBsAg containing hepatocytes generally did not show IgG fixed on their surface. IgG was not detected on the liver cell surface in 10 other HBsAg carriers without active disease and with large amounts of HBsAg containing hepatocytes. These results suggest that in HBsAg-positive chronic active hepatitis membrane-bound IgG is directed against viral antigens or virus-induced neoantigens that appear on the surface of infected cells at the time of active virus replication. Modulation of virus expression by this IgG could play a role in the pathogenesis of the disease.