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Selection of a multiple drug-resistant hepatitis B virus strain in a liver-transplanted patient.

Villet S, Pichoud C, Villeneuve JP, Trépo C, Zoulim F.

INSERM U271, Laboratoire des Virus Hépatiques et Pathologies Associées, 151 cours Albert Thomas, 69424 Lyon cedex 03, France.

BACKGROUND & AIMS: Sequential anti-hepatitis B virus (HBV) therapy may lead to the selection of complex mutants. We analyzed the genetic and phenotypic evolution of the viral quasispecies of a patient who received successively lamivudine, add-on adefovir+lamivudine, followed by lamivudine+adefovir+hepatitis B immunoglobulins (HBIg) after orthotopic liver transplantation. METHODS: For genotypic analysis, a 1310-bp region of the polymerase gene was amplified, cloned, and sequenced. Huh-7 cells were transfected to compare the replication fitness of HBV mutants and their susceptibility to drugs. RESULTS: At baseline, all HBV genomes carried a wild-type (wt) RT gene but 22% harbored the sP120S and 55% the sC107stop mutations within the surface (S) gene associated with vaccine escape. Following viral breakthrough to lamivudine monotherapy, a complex mixture of lamivudine-resistant HBV strains prevailed. Interestingly, among these mutants emerged a population harboring only the rtL180M+A181V mutations, conferring lamivudine-resistance in vitro. After addition of adefovir to the ongoing treatment, viral load dropped, and the patient underwent an orthotopic liver transplantation and received HBIg. As viral load rose again, a single viral population was progressively selected, harboring the rtV173L+L180M+A181V+N236T and sP120S mutations. In vitro, this last mutant showed a level of replication reduced by only 30% compared to wt HBV and a strong resistance to both lamivudine (>1000-fold) and adefovir (>10-fold). It remained sensitive to tenofovir both in vitro and in vivo. CONCLUSIONS: We report the selection of a complex HBV mutant that escaped the antiviral pressure of lamivudine, adefovir, and HBIg, and provide insight on the process of selection via genotypic and phenotypic analysis.

Publication Types:
PMID: 17030194 [PubMed - indexed for MEDLINE]