Quantitative DNA analysis of low-level hepatitis B viremia in two patientswith serologically negative chronic hepatitis B

Low-level viremia due to hepatitis B virus (HBV) was demonstrated in the se ra of two patients diagnosed previously as having non-B, non-C chronic hepa titis. Both patients had a "silent" HBV infection, because they were negati ve for both hepatitis:B surface antigen (HBsAg) and anti-hepatitis B core a ntibody. The TaqMan chemistry polymerase chain reaction (PCR) amplified the HBV DNA, enabling quantitation of the virus in their sera. Their serum HBV DNA concentrations were low: the amount of each HBV S or X gene amplified showed there were approximately 10(3) copies/ml and HBV DNA was detected oc casionally during clinical follow-up. Positive HBsAg staining in liver tiss ues was demonstrated by an immunoperoxidase technique. Vertical transmissio n of silent HBV from one patient to her daughter was confirmed. Direct nucl eotide sequencing of the amplified HBV X region revealed several mutations, suggesting reduced viral replication. One patient had a T-to-C mutation at the extreme 5'-terminus of the direct repeat 2 region and the other exhibi ted a coexisting X region with a 155-nucleotide deletion. These findings su ggest that HBV replication is suppressed considerably in patients with sile nt hepatitis B. J. Med. Virol. 58: 325-331 1999. (C) 1999 Wiley-Liss, Inc.