Lack of monomeric IgM anti-hepatitis C virus (HCV) core antibodies in patients with chronic HCV infection

Antibodies of the IgM class against the hepatitis C virus core antigen are found in up to 70% of patients with either acute or chronic hepatitis C. The sedimentation rate of such IgM was analyzed by rate-zonal centrifugation of nine sera taken from seven patients, two acutely and five persistently infected with hepatitis C virus. All patients had circulating high-molecular weight (i.e. pentameric) IgM, indicating that the production of low molecular weight IgM, commonly observed in other persistent viral infections, does not apply to hepatitis C virus and cannot be used to distinguish acute from chronic hepatitis C virus infection.