Summary auto-generated
This study compared hepatitis B virus (HBV) DNA sequences from peripheral blood mononuclear cells (PBMCs) and serum in 13 patients (5 with acute hepatitis, 8 with chronic hepatitis) to determine whether HBV replicates in PBMCs or merely adsorbs from serum. Researchers amplified HBV core promoter and precore region sequences and analyzed them using single-strand conformation polymorphism, direct sequencing, and cloning. Results showed identical HBV sequences in PBMCs and serum from all acute hepatitis patients and 5 of 8 chronic hepatitis patients, consistent with passive adsorption. However, in 3 chronic hepatitis patients, sequences differed between PBMCs and serum: two patients harbored HBV variants with deletions or insertions in PBMCs, and one had nucleotide substitutions. These sequence differences in PBMCs, likely caused by DNA topoisomerase I activity during active replication, suggest independent HBV replication occurs in PBMCs. The findings indicate that PBMCs may serve as extrahepatic replication sites and potential reservoirs for viral reinfection after transplantation or antiviral therapy.
Key findings
- Identical HBV sequences in PBMCs and serum from all acute hepatitis patients and 62.5% of chronic hepatitis patients suggest passive viral adsorption in most cases.
- Three chronic hepatitis patients showed different HBV DNA sequences between PBMCs and serum, including deletions, insertions, and nucleotide substitutions in PBMCs, indicating independent viral replication.
- Sequence variations in PBMCs are consistent with DNA topoisomerase I activity, an enzyme with high activity in lymphocytes that generates deletions and insertions during DNA recombination.
- PBMCs may serve as extrahepatic sites of HBV replication and potential reservoirs of original infecting virus strains.
- Findings support the hypothesis that extrahepatic HBV replication in PBMCs could be a source of reinfection after liver transplantation or antiviral therapy.
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Abstract
It has been reported that hepatitis B virus (HBV) DNA is present in peripheral blood mononuclear cells (PBMCs), although it is unclear whether it actually replicates there or is adsorbed from serum. HBV DNA sequences from the core promoter and precore regions were amplified from PBMCs and serum taken from 13 patients with hepatitis B infection. Analysis by single strand conformation polymorphism, direct sequencing and cloning revealed identical HBV DNA sequences in both PBMCs and serum from five patients with acute hepatitis and in five out of eight patients with chronic hepatitis. However, in the remaining three chronic hepatitis cases, HBV DNA sequences in both PBMCs and serum were different: two patients harboured HBV DNA sequences from their PBMCs with deletions/insertions in the core promoter region and one patient harboured HBV DNA sequences from their PBMCs with two nucleotide substitutions. These findings point to a possible presence of independent HBV DNA replication in PBMCs.