HBsAg quantification “Clinical applications” Philippe Halfon Philippe Sogni Michelle Martinot-Peignoux Definitions AgHBs: Protein, coating the surface of the HBV virion, secreted by the hepatocyte. Reflects indirectly the number of infected hepatocytes. cccDNA: Mini-chromosome produce in the nucleus, Acts as a template for transcription of viral gene. Required to maintain infection. Lower cccDNA levels correlate with lower serum HBsAg levels, indicating that HBsAg can be used as a surrogate marker of cccDNA. Volz T et al. Gastroenterolgy 2007;133:843 Thompson AJV et al. Hepatology 2010;51:1933 AgHBs and ADNccc Serum HBsAg levels reflects cccDNA in infected cells • cccDNA (matrix necessary for the viral replication) level reflect the number of infected hepatocytes. • cccDNA levels lower in e-negative than in e-positive patients. • cccDNA and serum HBsAg titer show a significant correlation. • Serum HBsAg level is considered as indirect scorer of HBV infected hepatocytes. Volz et al. Gastroenterology 2007. HBsAg quantification HBsAg assay automate Architect (Abbott) HBsAg II Quant Elecsys or Cobas (Roche) Liaison XL HBsAg Quant assay (DiaSorin) Quantification is not dependent of the presence of AgHBs/antiHBs (5-25%) Useful tool in the diagnosis and the follow-up of the patients with chronic hepatitis B Pancher M, Thibault V, et al. J Clin Virol 2014 on line Correlation between HBsAg and HBV DNA HBeAg negative 10 10 9 9 8 7 6 5 4 3 r2=0.438; p < 0.01 2 1 HBV DNA log10 UI/ml HBV DNA log10UI/ml HBeAg positive 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 AgHBs log10 UI /ml Martinot-Peignoux et al. J Hepatol 2013; in Press 7 r2=0.109; ns 0 1 2 3 4 5 6 AgHBs log10 UI /ml 7 HBsAg Natural History HBeAg positive HBeAg negative Serum HBsAg levels vary significantly during the different phases of chronic HBV infection and are inversely correlated with the immune control of HBV: the higher control, the lower HBsAg level Nguyen T. et al. J Hepatol 2010;52;508 Chan et al Hepatology 2010;52:1232 Jaroszewicz. et al. J Hepatol 2010;52;514 Martinot-Peignoux et al. Hepatology 2010;52:992A Natural History: HBV genotype HBsAg log10UI/ml * 6 5 4 3.93 ± 0.91 3.84 ± 0.90 3 3.97 ± 0.60 3.74 ± 0.84 3.23 ± 1.12 2 1 0 -1 A B * B versus A, C D and E p<0.0001 C D E Martinot-Peignoux et al. AASLD 2011 Natural History: HBV genotype HBeAg positive HBeAg negative Units HBsAg log10IU/ml HBsAg log10IU/ml 6 6 5 5 4 4 3 3 2 4.56 ± 0.51 4.16 ± 0.88 1 4.08 ± 1.17 2 4.59 ± 0.54 4.06 ± 0.88 3.28 ± 0.76 1 3.74 ± 0.75 0 0 -1 -1 A B C D E 3.58 ± 0.80 2.96 ± 1.04 A B HBeAg pos versus HBe Ag neg p< 0.01 Martinot-Peignoux et al.J Hepatol 2013 in Press 3.83 ± 0.50 C D E Clinical utility HBsAg reliable marker HBsAg log IU/ml 11 10 9 8 7 6 5 4 3 2 1 0 0 Martinot-Peinoux Liver International 2013:125:132 HBV DNA log UI/ml ALT (xN) 10 ans 11 10 9 8 7 6 5 4 3 2 1 0 Martinot-Peignoux et al. J Clin Virol 2013;58:401 Prediction of severity 406 patients AgHBe positive / negative génotype A à E r=0.43; p<0.0001 ns ns ns Martinot-Peignoux et al. J Hepatol 2013;58:1089 80 % Prediction of HBs loss HBsAg < 100 IU/ml 60 HBsAg 100-999 IU/ml 0 20 40 HBs Ag> 1000 IU/ml 1 3 Tseng et al, Gastroenterology 2011 5 7 9 11 13 15 years PEG-IFN therapy HBV DNA and HBsAg kinetics HBV DNA levels Rechuteurs Rechuteurs RVS Moucari et al. Hepatology 2009;49:1151 Brunetto et al., Hepatology 2009;49:1141 RVS During therapy HBeAg seroconversion 6 months post-treatment Low on-treatment HBsAg levels associated with higher HBeAg seroconversion rates Phase 3 study NEPTUNE study 57% < 1500 58% 1500-20.000 > 20.000 < 1500 1500-20.000 > 20.000 Week 12 HBsAg titer Piratvisuth T et al.,(APASL 2010 Lau G. et al. EASL 2009 Gane E et al. EASL 2011 Liaw et al. Hepatology 2012 IU/ml When: during therapy (NAs) Early on treatment HBsAg decrease is predictive: Sustained virological response and HBsAg loss Week 12 Week 24 HBsAg decrease PPV NPV PPV NPV 0.5 log IU/ml 5% 85% 0% 85% <1 log IU/ml 35% 95% 41% 97% Marcellin P et al N Eng J Med 2008 Marcellin P. et al AASLD 2012. Conclusion (1) • Quantifying HBsAg is an important tool for predicting the chronic hepatitis B outcome: - severity of liver disease, - cirrhosis and HCC development, - identification of inactive carriers (<1 000 IU/ml) • Help to tailor follow-up and treatment management - Decline during PEG-IFN strong predictor of SVR - Decline during NAs predictor of HBsAg loss Volz T et al. Gastroenterolgy 2007;133:843 Thompson AJV et al. Hepatology 2010;51:1933
