Detection of hepatitis B virus DNA in the liver and serum of patients with hepatitis B surface antigen and hepatitis C virus antibody negative chronic liver disease.

To elucidate the positive frequency of hepatitis B virus (HBV) DNA in patients with hepatitis B surface antigen (HBsAg) and antibody to hepatitis C virus (HCVAb) negative (NBNC) chronic liver disease, we detected serum HBV-DNA using the real-time detection polymerase chain reaction method (RTD-PCR) in comparison with HBsAg and HCVAb negative individuals with normal alanine aminotransferase (ALT). We also revealed the nucleotide sequence of the X-pre-C gene-coding region of intrahepatic HBV-DNA. Serum HBV-DNA was detected in 12 of 36 NBNC patients (five of 22 chronic hepatitis, three of eight liver cirrhosis and four of six hepatocellular carcinoma), whereas none of 31 control individuals were positive for serum HBV-DNA (P<0.01). Serum antibody to hepatitis B core antigen (HBcAb) was positive in nine of 36 in patients with NBNC patients and was positive in nine of 31 in control individuals (n.s). Five of six NBNC patients with serum HBV-DNA positive by RTD-PCR were also positive for intrahepatic HBV-DNA. Analysis of the nucleotide sequence of the X-pre-C coding region of HBV-DNA in the liver showed similar mutation sites of 1677, 1679, 1709, 1753, 1762, 1764. These findings suggested that serum HBV-DNA was more frequently detected in NBNC patients than normal individuals and the presence of low levels of serum HBV-DNA was correlated to the 1677--1764 X-pre-C mutations.