TRANSCRIPTION OF HEPATITIS-B VIRUS IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS FROM PERSISTENTLY INFECTED PATIENTS

Hepatitis B virus (HBV) has been reported to exist in peripheral blood mononuclear cells (PBMC), but it is not clear whether it replicates t here. A precondition for replication should be the formation of covale ntly closed viral DNA and transcription of all essential viral mRNAs. The mRNAs of HBV form a nested box with common 3' ends. In order to de tect even low levels of potential replication, we developed a quantita tive reverse transcription-PCR method for detection of a smaller HBV m RNA species in the presence of the larger ones. All three highly virem ic patients tested so far had mRNAs for the large and the small surfac e proteins and the X protein of the virus within PBMC but not in the v irus from their sera. Furthermore, we detected by PCR covalently close d viral DNA in their PBMC. These data suggest that HBV may be not only taken up but also replicated by mononuclear blood cells and that thes e cells may be an extrahepatic site of viral persistence. X mRNA was d etected in the largest amount. Possibly, X protein interferes with fun ctions of the mononuclear cells during the immune response against the virus.