ĐẶC ĐIỂM ĐỘT BIẾN GEN PRES/S CỦA VIRUS VIÊM GAN B (HBV) Ở NGƯỜI DÂN TỘC THIỂU SỐ MANG HBSAG TẠI THÁI NGUYÊN

Abstract

Objective: To describe the genotype characteristics and mutations in the PreS/S region of the hepatitis B virus (HBV) in HBsAg-positive ethnic minority university students in Thai Nguyen, Vietnam. Materials and Methods: A cross-sectional descriptive study was conducted on 272 serum samples collected in 2024 from ethnic minority university students. Samples were screened for HBsAg using a rapid test and quantified for anti-HBs and anti-HBc using ELISA. HBV DNA was extracted, and the PreS/S region was amplified using nested PCR, sequenced via Sanger sequencing, and analyzed for mutations using BioEdit, MEGA 11, and Geno2pheno software. Results: HBV DNA was detected in 5 out of 272 samples (1.8%), all of which were from female participants belonging to the Dao and Tay ethnic groups, with HBsAg positivity and anti-HBs levels ranging from 0 to 13.9 mIU/mL. Phylogenetic analysis revealed that 2 samples belonged to genotype B and 3 to genotype C. A total of 21 mutation sites were identified in the PreS/S region, many of which were missense mutations. Notably, the L109P, S117N, and K122R mutations were located near the “a determinant” region, potentially affecting the surface structure and antigenicity of HBsAg. Conclusion: This study recorded genetic diversity of HBV genotypes B and C accompanied by characteristic PreS/S mutations among HBsAg-positive ethnic minority students. Some mutations may be associated with alterations in HBsAg antigenic structure, providing a basis for future research on the performance of HBsAg detection assays and mechanisms of HBV immune escape.