title: Successful interferon treatment in a patient chronically infected with hepatitis B virus carrying unusual S- (and P-) mutants in the presence of anti-HBs antibodies.
abstract: BACKGROUND
  Hepatitis B virus (HBV) immune escape mutants with point mutations within the S gene may arise during the natural course of HBV infection, due to a positive selection pressure exerted by the host immune response. Mutations within the immunodominant B and T cell epitopes of hepatitis B surface antigen (HBsAg) allow the resulting S-mutants to propagate even in the presence of neutralizing anti-HBs antibodies and the HBV-specific T-cell immune response.
  
  
  OBJECTIVE
  To study the antiviral effect of Pegylated-interferon (Peg-IFN) in a patient with chronic hepatitis B carrying unusual S-(and P-) mutants in the presence of anti-HBs antibodies.
  
  
  RESULTS
  We report on a 43-year-old male chronically infected with a genotype A HBV strain, with cocirculation of both HBsAg and anti-HBs antibodies, who received treatment with 120 mug of Peg-IFN for 24 weeks. HBeAg seroconversion and clearance of both HBV DNA by polymerase chain reaction and HBsAg were successfully achieved. Improved histology was observed in a biopsy performed 44 weeks after Peg-IFN therapy was completed. It seems plausible that the ascribed genotype A could have contributed to the effective response to Peg-IFN, even though the treatment was provided only throughout a 24-week period.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report regarding the successful result obtained by using Peg-IFN as a treatment for a chronically HBV-infected patient carrying HBsAg immune escape mutants.
authors.affiliation: Departamento de Medicina - Hepatología, Hospital Argerich, Asociado a la Universidad de Buenos Aires (UBA), Buenos Aires, Argentina. bernardo@frider.com.ar
authors.forename: Bernardo
authors.initials: B
authors.lastname: Frider
authors.forename: Analía
authors.initials: A
authors.lastname: Alessio
authors.forename: Marcia
authors.initials: M
authors.lastname: Pozzati
authors.forename: María L
authors.initials: ML
authors.lastname: Cuestas
authors.forename: Verónica L
authors.initials: VL
authors.lastname: Mathet
authors.forename: José R
authors.initials: JR
authors.lastname: Oubiña
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use*; D008297:Male; D009154:Mutation; D011092:Polyethylene Glycols; D011994:Recombinant Proteins
chemical_list: D000998:Antiviral Agents; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins; D011092:Polyethylene Glycols; C417083:peginterferon alfa-2b