Serum hepatitis B surface antigen and hepatitis B e antigen titers: disease phase influences correlation with viral load and intrahepatic hepatitis B virus markers.
Although threshold levels for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) titers have recently been proposed to guide therapy for chronic hepatitis B (CHB), their relationship to circulating hepatitis B virus (HBV) DNA and intrahepatic HBV replicative intermediates, and the significance of emerging viral variants, remains unclear. We therefore tested the hypothesis that HBsAg and HBeAg titers may vary independently of viral replication in vivo. In all, 149 treatment-naïve CHB patients were recruited (HBeAg-positive, n = 71; HBeAg-negative, n = 78). Quantification of HBeAg and HBsAg was performed by enzyme immunoassay. Virological characterization included serum HBV DNA load, HBV genotype, basal core promoter (BCP)/precore (PC) sequence, and, in a subset (n = 44), measurement of intrahepatic covalently closed circular DNA (cccDNA) and total HBV DNA, as well as quantitative immunohistochemical (IHC) staining for HBsAg. In HBeAg-positive CHB, HBsAg was positively correlated with serum HBV DNA and intrahepatic cccDNA and total HBV DNA (r = 0.69, 0.71, 0.76, P < 0.01). HBeAg correlated with serum HBV DNA (r = 0.60, P < 0.0001), although emerging BCP/PC variants reduced HBeAg titer independent of viral replication. In HBeAg-negative CHB, HBsAg correlated poorly with serum HBV DNA (r = 0.28, P = 0.01) and did not correlate with intrahepatic cccDNA nor total HBV DNA. Quantitative IHC for hepatocyte HBsAg confirmed a relationship with viral replication only in HBeAg-positive patients.


CONCLUSIONS
The correlation between quantitative HBsAg titer and serum and intrahepatic markers of HBV replication differs between patients with HBeAg-positive and HBeAg-negative CHB. HBeAg titers may fall independent of viral replication as HBeAg-defective variants emerge prior to HBeAg seroconversion. These findings provide new insights into viral pathogenesis and have practical implications for the use of quantitative serology as a clinical biomarker.
Thompson
Alexander J V
AJ
Department of Research and Molecular Development, Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia.
Nguyen
Tin
T
Iser
David
D
Ayres
Anna
A
Jackson
Kathy
K
Littlejohn
Margaret
M
Slavin
John
J
Bowden
Scott
S
Gane
Edward J
EJ
Abbott
William
W
Lau
George K K
GK
Lewin
Sharon R
SR
Visvanathan
Kumar
K
Desmond
Paul V
PV
Locarnini
Stephen A
SA
D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006513:Hepatitis B e Antigens / Q000097:blood*; D019694:Hepatitis B, Chronic / Q000276:immunology / Q000821:virology*; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000821:virology; D008297:Male; D008875:Middle Aged; D019562:Viral Load; D014779:Virus Replication
D015415:Biomarkers; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens