title: Hepatitis B surface antigen quantification: why and how to use it in 2011 - a core group report.
abstract: Quantitative HBsAg had been suggested to be helpful in management of HBV, but assays were cumbersome. The recent availability of commercial quantitative assays has restarted the interest in quantitative serum hepatitis B surface antigen (HBsAg) as a biomarker for prognosis and treatment response in chronic hepatitis B. HBsAg level reflects the transcriptional activity of cccDNA rather than the absolute amount of cccDNA copies. Serum HBsAg level tends to be higher in hepatitis B e antigen (HBeAg)-positive than HBeAg-negative patients. Among patients with a low HBV DNA (<2000IU/ml), HBsAg <1000IU/ml in genotype D HBV infection and HBsAg <100IU/ml in genotype B/C HBV infection is associated with inactive carrier state in HBeAg-negative patients. The HBsAg reduction by nucleos(t)ide analogues (NA) is not as pronounced as by interferon treatment. On peginterferon treatment, sustained responders tend to show greater HBsAg decline than the non-responders. The optimal on-treatment HBsAg cutoff to predict response needs further evaluation in HBeAg-positive patients, but an absence of HBsAg decline together with a <2 log reduction in HBV DNA at week 12 can serve as stopping rule in HBeAg-negative patients with genotype D HBV infection. A rapid serum HBsAg decline during NA therapy may identify patients who will clear HBsAg in the long-term. There are early reports among Asian patients that an HBsAg level of <100IU/ml might predict lower risk of relapse after stopping NA treatment. In clinical practice, serum HBsAg level should be used together with, but not as a substitute for, HBV DNA.
authors: Department of Medicine and Therapeutics and Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong. hlychan@cuhk.edu.hk
authors: Henry Lik-Yuen
authors: HL
authors: Chan
authors: Alex
authors: A
authors: Thompson
authors: Michelle
authors: M
authors: Martinot-Peignoux
authors: Teerha
authors: T
authors: Piratvisuth
authors: Markus
authors: M
authors: Cornberg
authors: Maurizia Rossana
authors: MR
authors: Brunetto
authors: Hans L
authors: HL
authors: Tillmann
authors: Jia-Horng
authors: JH
authors: Kao
authors: Ji-Dong
authors: JD
authors: Jia
authors: Heiner
authors: H
authors: Wedemeyer
authors: Stephen
authors: S
authors: Locarnini
authors: Harry L A
authors: HL
authors: Janssen
authors: Patrick
authors: P
authors: Marcellin
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006513:Hepatitis B e Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000276:immunology* / Q000502:physiology; D019694:Hepatitis B, Chronic / Q000175:diagnosis* / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use; D011092:Polyethylene Glycols / Q000627:therapeutic use; D011379:Prognosis; D011994:Recombinant Proteins / Q000627:therapeutic use; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens; D016898:Interferon-alpha; D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; D011092:Polyethylene Glycols; C100416:peginterferon alfa-2a