Public Release Type:
Journal
Publication Year: 2014
Authors:
Janssen HLA,
Brouwer WP,
Cloonan YK,
Feld JJ,
Fried MW,
Perrillo RP,
Wong DK
Studies:
Hepatitis B Research Network
Background and Aims: HBsAg-levels reflect the interaction between the immune system and the hepatitis B virus (HBV) and are used as a predictor of response to interferon. However, large studies investigating all major HBV-genotypes and their impact on HBsAg-levels during the course of HBV-infection are lacking. Methods: At 22 US/Canadian centres, 1745 HBV-infected adults were enrolled. Analyses included non-treated participants with chronic HBV mono-infection, with available data on HBsAg-levels, ALT, HBVDNA-levels and HBV-genotype. Disease phenotypes were defined using HBeAg-status, ALT and HBVDNA-levels. Overall and within HBV-genotype, median HBsAg-levels were compared across phenotype using Kruskal–Wallis tests. Results: In total, 741 participants were analyzed. Median age was 42 years, 51% were male and 75% were Asian. Fifty-three (7%) were immune tolerant (IT), 101 (14%) HBeAg(+) active (IA+), 120 (16%) HBeAg(−) active (IA−), 202 (27%) inactive carriers (IC) and 265 (36%) indeterminate (ID). The most common HBVgenotypes were A (17%), B (37%), C (34%) and D (8%). HBsAglevels differed across phenotypes (p < 0.01), with highest levels observed in IT (median = 4.8 log10 IU/ml; IQR = 4.4–4.9), and lowest in IC (median = 3.1 log10 IU/ml; IQR = 2.1–3.7). Also, median HBsAglevels (log10IU/mL) differed across HBV-genotypes and were 4.0 (A), 3.0 (B), 3.5 (C) and 3.3 (D) (p < 0.01). Within HBV-genotype, HBsAglevels differed across phenotype (p < 0.01 for HBV-genotype A–C, and p = 0.04 for genotype D; figure). Interestingly, mean HBsAglevels for IC infected with HBV-genotype A were comparable to HBsAg-levels of IA+ in the other HBV-genotypes investigated. Conclusions: HBsAg-levels differ by both HBV-genotype and phenotype, with highest levels observed in immune-tolerant participants and those infected with HBV-genotype A. HBsAglevels could help to differentiate between disease phenotypes, but primarily among participants with the same HBV-genotype.