Work

HBV genotype distribution and S gene mutations in HIV-HBV co-infected patients: insights from North India

Year: 2026

Type: article

Abstract: Purpose: Effective HBV therapy and immunisation require knowledge of HBV mutation rate and genetic variability. This study aimed to characterize HBV genotypes, serotypes, and surface (S) gene mutations among HBV-HIV co-infected and HBV mono-infected patients in North India. Methods: A total of 100 HBV-HIV co-infected and 50 HBV mono-infected patients were enrolled. HBV DNA was extracted from serum using the QIAamp DNA Blood Mini Kit (QIAGEN). HBV viral load was quantified by real-time PCR. The HBV surface gene was amplified using conventional and nested PCR, followed by Sanger sequencing for genotyping, serotyping, and mutational analysis. Genotypes were additionally confirmed using type-specific multiplex PCR. Results: The mean age of HIV-HBV co-infected and HBV mono-infected patients was 36.6 and 34.9 years, respectively. HBeAg positivity was observed in 17% of co-infected and 10% of HBV mono-infected cases. HBV surface gene was successfully amplified in 19 (19%) HIV-HBV co-infected and 20 (40%) HBV mono-infected samples. Genotype D predominated (35/39, 89.7%), with subgenotypes D1 and D3 detected at comparable frequencies, while genotype A was identified in 4 (10.3%) samples, all belonging to subgenotype A1. Serotype analysis showed exclusive association of genotype D with ayw2 and genotype A with adw2. Mutations within the HBsAg 'a' determinant region were identified in 36.8% of HBV-HIV co-infected patients, including nonsynonymous substitutions, whereas no such mutations were observed in HBV mono-infected individuals. Genotype D sequences clustered with subgenotypes D2, D3, and D9 (from West Bengal), as well as D3 (from Russia, Madhya Pradesh, Delhi and Brazil). Conclusion: This study confirms the predominance of HBV genotype D with serotype ayw2 in North India and demonstrates a higher frequency of HBsAg immune escape-associated mutations in HBV-HIV co-infected patients. These findings underscore the importance of ongoing molecular surveillance to inform diagnostic strategies, vaccination effectiveness, and clinical management of HBV, particularly in HIV-affected populations.

Source: Frontiers in Cellular and Infection Microbiology

DOI: 10.3389/fcimb.2025.1731472