Hepatitis B virus infection: detection of circulating HBsAg/IgM antibody immune complexes.

Circulating hepatitis B surface antigen (HBsAg) IgM antibody complexes have been described in patients infected with hepatitis B virus (HBV). A radioimmunoassay to test for these complexes was developed and compared with a commercial kit. Complexes were demonstrated in both test systems. HBsAg/IgM antibody complexes were present initially in patients with acute HBV infection but disappeared within an average of 6 weeks after onset. In HBV carriers immune complexes persisted over a long time. This test is of value in providing additional information about the outcome of HBV infections and sequential testing for HBsAg/IgM is of prognostic value for clinicians.