Molecular characteristics of occult hepatitis B virus from blood donors in southeast China

Area of Science:

• Virology
• Hepatology
• Infectious Diseases

Background:

• Occult hepatitis B virus (HBV) infection presents a diagnostic challenge as individuals test negative for surface antigen (HBsAg) but remain infectious.
• Understanding the molecular characteristics of occult HBV is crucial for preventing transmission and managing chronic carriers.

Purpose of the Study:

• To compare the virological and genetic characteristics of occult HBV infection (OBI) with other hepatitis B virus (HBV) infection states.
• To identify specific HBV genotypes and mutations associated with occult HBV infection.

Main Methods:

• Comparative analysis of 30 occult HBV carriers against 30 HBV carriers detected at blood donation, 60 asymptomatic carriers, and 60 chronic hepatitis patients.
• Genotyping of HBV isolates.
• Analysis of amino acid substitutions within the S gene, particularly in the major hydrophilic region (amino acids 117-121 and 144-147).

Main Results:

• Genotype C was significantly more prevalent in occult HBV carriers compared to other HBsAg-positive groups (P < 0.001).
• Specific amino acid substitutions in the S gene regions (aa 117-121 and 144-147) were significantly associated with occult HBV infection (P < 0.01).
• The G145R substitution was identified as the predominant variation in HBV isolates from occult HBV infections.

Conclusions:

• Occult HBV infection is associated with a distinct genotypic profile, notably a higher prevalence of genotype C.
• Specific mutations in the HBV S gene, including G145R, play a significant role in the pathogenesis and presentation of occult HBV infections.
• These findings contribute to a better understanding of occult HBV epidemiology and may inform diagnostic and therapeutic strategies.