Serum hepatitis B virus-DNA in chronic hepatitis B and delta infection.

Hepatitis B-associated delta agent, a defective RNA virus requiring helper functions of hepatitis B virus (HBV), has been shown to interfere with HBV replication. Low titers of serum hepatitis B surface antigen, absence of hepatitis B e antigen, and low levels of stainable hepatitis B core antigen in liver cells usually seen in chronic delta infection are indirect evidences of such an interference. Measurement of serum HBV-DNA by hybridization with phosphorus 32-labeled HBV-clone DNA is the most sensitive method currently available to detect HBV replication. Using this method, we found that only two of 13 patients with chronic delta infection showed serum HBV-DNA positivity in comparison with seven of 14 patients who had chronic hepatitis B without delta infection. These two groups were matched for hepatitis B e antigen status and liver histopathology. Thus, we report direct evidence of delta agent interfering with the replication of the helper (HBV) virus.