title: Specific mutations in the C-terminus domain of HBV surface antigen significantly correlate with low level of serum HBV-DNA in patients with chronic HBV infection.
abstract: BACKGROUND
  To define HBsAg-mutations correlated with different serum HBV-DNA levels in HBV chronically-infected drug-naive patients.
  
  
  METHODS
  This study included 187 patients stratified into the following ranges of serum HBV-DNA:12-2000 IU/ml, 2000-100,000 IU/ml, and >100,000 IU/ml. HBsAg-mutations were associated with HBV-DNA levels by applying a Bayesian-Partitional-Model and Fisher-exact test. Mutant and wild-type HBV genotype-D genomes were expressed in Huh7 cells and HBsAg-production was determined in cell-supernatants at 3 days-post-transfection.
  
  
  RESULTS
  Specific HBsAg-mutations (M197T,-S204N-Y206C/H-F220L) were significantly correlated with serum HBV-DNA <2000 IU/ml (posterior-probability>90%, P < 0.05). The presence of Y206C/H and/or F220L was also associated with lower median (IQR) HBsAg-levels and lower median (IQR) transaminases (for HBsAg:250[115-840] IU/ml for Y206C/H and/or F220L versus 4300[640-11,838] IU/ml for wild-type, P = 0.023; for ALT:28[21-40] IU/ml versus 53[34-90] IU/ml, P < 0.001). These mutations were localized in the HBsAg C-terminus, known to be involved in virion and/or HBsAg secretion. The co-occurrence of Y206C + F220L was found significant by cluster-analysis, (P = 0.02). In addition, in an in-vitro model Y206C + F220L determined a 2.8-3.3 fold-reduction of HBsAg-amount released in supernatants compared to single mutants and wt (Y206C + F220L = 5,679 IU/ml; Y206H = 16,305 IU/ml; F220L = 18,368 IU/ml; Y206C = 18,680 IU/ml; wt = 14,280 IU/ml, P < 0.05).
  
  
  CONCLUSIONS
  Specific HBsAg-mutations (compartmentalized in the HBsAg C-terminus) correlated with low-serum HBV-DNA and HBsAg-levels. These findings can be important to understand mechanisms underlying low HBV replicative potential including the inactive-carrier state.
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Mirabelli
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Surdo
authors.affiliation: Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, 1000 Amsterdam, The Netherlands.
authors.forename: Formijn
authors.initials: F
authors.lastname: Van Hemert
authors.affiliation: Yale University, New Haven, CT 06520 United States.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Lian
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Romina
authors.initials: R
authors.lastname: Salpini
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Cento
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Cortese
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Aragri
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Pollicita
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Alteri
authors.affiliation: University Hospital of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Ada
authors.initials: A
authors.lastname: Bertoli
authors.affiliation: Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, 1000 Amsterdam, The Netherlands.
authors.forename: Ben
authors.initials: B
authors.lastname: Berkhout
authors.affiliation: "L. Sacco" Hospital, 20157 Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Micheli
authors.affiliation: "L. Sacco" Hospital, 20157 Milan, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Gubertini
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Maria Mercedes
authors.initials: MM
authors.lastname: Santoro
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Romano
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Visca
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Bernassola
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Longo
authors.affiliation: "La Sapienza" University 00100 Rome, Italy.
authors.forename: Giuseppe Maria
authors.initials: GM
authors.lastname: De Sanctis
authors.affiliation: Virology Laboratory, Centre Hospitalier Régional et Université "Victor Segalen", CHU de Bordeaux, 33300 Bordeaux, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Trimoulet
authors.affiliation: Virology Laboratory, Centre Hospitalier Régional et Université "Victor Segalen", CHU de Bordeaux, 33300 Bordeaux, France.
authors.forename: Hervè
authors.initials: H
authors.lastname: Fleury
authors.affiliation: "Santa Maria Annunziata" Hospital, 50100 Florence, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Marino
authors.affiliation: "Santa Maria Annunziata" Hospital, 50100 Florence, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Mazzotta
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Cappiello
authors.affiliation: Microbiology and Virology Unit, "S. Pertini" Hospital, 00100 Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Spanò
authors.affiliation: University Hospital of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Sarrecchia
authors.affiliation: Yale University, New Haven, CT 06520 United States.
authors.forename: Jing Maria
authors.initials: JM
authors.lastname: Zhang
authors.affiliation: University Hospital of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Andreoni
authors.affiliation: University Hospital of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Angelico
authors.affiliation: Institute of Virology, University Hospital, 45147 Duisburg-Essen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Verheyen
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy; University Hospital of Rome "Tor Vergata", 00100 Rome, Italy.
authors.forename: Carlo Federico
authors.initials: CF
authors.lastname: Perno
authors.affiliation: Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00100 Rome, Italy. Electronic address: valentina.svicher@uniroma2.it.
authors.forename: Valentina
authors.initials: V
authors.lastname: Svicher
mesh_terms: D000328:Adult; D001499:Bayes Theorem; D002353:Carrier State / Q000821:virology; D004279:DNA, Viral / Q000097:blood*; D005260:Female; D005838:Genotype; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000737:chemistry / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D000637:Transaminases / Q000097:blood
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D000637:Transaminases
keywords: HBV; HBsAg; Serum HBV-DNA; Virion maturation