title: Prolonged persistence of lamivudine-resistant mutant and emergence of new lamivudine-resistant mutants two years after lamivudine withdrawal in HBsAg-positive chronic hepatitis patient: a case report.
abstract: Lamivudine can select resistant hepatitis B virus (HBV) tyrosine-methionine-aspartate-aspartate aminoacid motif (YMDD) mutants, which usually disappear in few months after lamivudine withdrawal. We report an unusual case of a male adult patient who showed a prolonged persistence of the M204I mutation up to 24 months after lamivudine withdrawal followed by the emergence of new distinct YMDD mutants (namely M204V, V207L). Only 42 months after lamivudine withdrawal wild-type YMDD motif became dominant over the YMDD mutants. To our knowledge, a so prolonged persistence of a YMDD mutant and also the emergence of new YMDD mutants many months after drug withdrawal are unusual.
authors.affiliation: Department of Public Medicine and Social Security, Section of Infectious Diseases, University of Naples Federico II, Via Sergio Pansini 5, Naples, Italy. raffaele.orlando@unina.it
authors.forename: R
authors.initials: R
authors.lastname: Orlando
authors.forename: G
authors.initials: G
authors.lastname: Tosone
authors.forename: G
authors.initials: G
authors.lastname: Portella
authors.forename: E
authors.initials: E
authors.lastname: Veropalumbo
authors.forename: M
authors.initials: M
authors.lastname: D'Onofrio
authors.forename: M
authors.initials: M
authors.lastname: Piazza
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008297:Male; D009154:Mutation; D028761:Withholding Treatment
chemical_list: D000998:Antiviral Agents; D006514:Hepatitis B Surface Antigens; D019259:Lamivudine