Concomitant Serum Presence of Hepatitis B Surface Antigen (HBsAg) and High Titers of Hepatitis B Surface Antibodies (Anti - HBsAb) in a Patient with Chronic Hepatitis B (HBV) Genotype D from Black Sea Coast Region: A Case Report

Hepatitis B Virus genotypes influence chronic hepatitis B evolution and show geographic preferences. In Eastern Europe, HBV - D genotype seems to be dominant, still, without enough information regarding the prevalence of its four subtypes. In addition, treatment with Nucleos(t)ide Analogues (NUCs) has lower impact on HBV - D genotype clearance compared to others. This study aimed at presenting the case of a middle age female diagnosed, followed - up and treated for eight years with entecavir 0.5 mg/day, in whom an increase of anti - HBsAb titer was noted over the immunogenicity level and undetectable viremia, despite the continuous presence of HBsAg. This is an uncommon type of evolution, most patients with anti-HBsAb over 10 IU/mL show seroconversion in the “s” system in a few months.
The researchers used the COBAS TaqMan HBV Monitor Test (Roche Diagnostics, Branchburg, NJ) in order to measure serum HBV DNA level, then, the viral DNA was extracted from 200 μL of serum using QIAamp DNA blood mini kit (Qiagen, Germany). The amplification and sequencing of full DNA length was done by the Rolling Circle Amplification (RCA) technique. Hepatitis B Virus genotype was determined using the NCBI genotyping tool and phylogenetic analysis.
The patient was proved to have D genotype. The DNA analyzes showed escape mutations in the “a” determinant within the S gene, represented by sQ129R, respectively, sI134T, reported by the literature in a small number of C genotype patients. The paradoxical serum profile of the current patient with positive HBsAg, increased titers of anti - HBsAb, and undetectable viral load could be a possible model of evolution for D genotype HBV chronic infected patients treated with NUCs, cohort genetic studies on patients with the same serum profile are required to confirm this pattern of evolution.