Clinical significance of quantitative e antigen in a cohort of hepatitis B virus-infected children and adults in North America

Background: In chronic hepatitis B (CHB) viral infection, e antigen positivity (HBeAg+) is associated with high levels of viral replication and infectivity. Furthermore, HBeAg-positive CHB is associated with a liver disease spectrum ranging from none to severe. Aim: To assess whether the level of circulating HBeAg is associated with different clinical presentations of HBeAg-positive CHB. Methods: A cross-sectional analysis was conducted among HBV mono-infected participants enrolled in Hepatitis B Research Network (HBRN) cohorts to explore clinical and virological associations with quantitative HBeAg (qHBeAg). Results: Among 763 HBeAg+ participants (56% female; 85% Asian; median age 26 years), multivariable median regression modelling significantly associated qHBeAg with liver injury (inverse qHBeAg association with ALT p<.001 and APRI p<.001), and with both race and age (p=0.01). Among Asians, qHBeAg was inversely related to age; a relationship less clear among Blacks and Whites. Among Asians also, median qHBeAg levels were higher among those infected with HBV genotype C versus B (p<0.001), suggesting causal virologic differences. Across all races, median qHBeAg was higher in women (p=.01). Independent of sex, age, race and HBV genotype, qHBeAg was higher in participants with predominant wild-type versus basal core promoter and/or precore ‘stop’ viral variants (p<0.001). Conclusion: Lower qHBeAg was observed among HBRN participants with the greatest degree of liver injury independent of demographics and HBV genotype. These data support longitudinal studies to examine the role of qHBeAg in modulating the host immune response and predicting the outcomes of chronic HBV infection.