Abstract

Characterization of hepatitis B virus (HBV) quasispecies in different compartments in liver transplant (LT) recipients may help optimize prophylaxis regimens.

AIMS: To evaluate liver, peripheral blood mononuclear cells (PBMC) and plasma for HBV and compare quasispecies in hepatic vs. extrahepatic sites in LT recipients on long-term prophylaxis.

METHODS: Liver, plasma and PBMC from 12 patients followed for up to 15 years post-LT (all HBV DNA negative by conventional PCR assays) were evaluated for HBV DNA by sensitive nested PCR, covalently closed circular DNA (cccDNA) in liver/PBMC, and sequencing, and phylogenetic analysis of polymerase (P) quasispecies.

RESULTS: In 10 patients with no clinical recurrence on prophylaxis (median post-LT 15.5 mo, range 12-96), 9/10 of liver, 3/10 of plasma, and 2/7 of PBMC were HBV DNA-reactive, including one with HBV cccDNA in PBMC. Sequence analysis showed all HBV clones with wild-type sequence in liver and PBMC. In 2 patients with early HBV recurrence post-LT, treated with nucleosides only, HBV DNA was detected in serum, PBMC and liver and HBV cccDNA was found in liver. HBV M204I lamivudine resistant (LMVr) variant was identified in liver (66% and 70% clones) and in plasma (100% clones), but wild-type sequence in 100% of PBMC clones.

CONCLUSIONS: Despite prophylaxis and absence of HBV DNA by conventional assays, HBV is detectable in serum, liver and PBMC in almost all patients, supporting the use of continued anti-HBV therapy in this group. Antiviral drug resistant variants are more frequent in liver than in PBMC but both compartments are potential sources for reinfection.