Significance of screening antibodies to hepatitis B virus core antigen among Syrian blood donors

Antibodies to Hepatitis B core antigen prevalence study in Kazakhstan

INTRODUCTION

Kazakhstan is being considered medium-endemic for Hepatitis B virus infection (HBV). HBV remains transmissible by direct exposure to infected blood or organic fluids. This cross-sectional study aimed to evaluate the prevalence of anti-HBcore and the risk factors impacting positive anti-HBcore markers among donors at Scientific-Production Center of Transfusiology, Ministry of Healthcare of the Republic of Kazakhstan.

MATERIALS AND METHODS

The samples taken from blood donors were tested for anti-HBcore, by the chemiluminescence immunoassay method on the Architect i2000SR (Abbott). In case of positive anti-HBcore, the blood samples were further tested for anti-HBs on the Architect i2000SR (Abbott). Alanine aminotransferase (ALT) indicators were tested by kinetic method on the Biosystems A25 analyzer. Statistical analysis was conducted using R software (version 4.1.1, 2021).

RESULTS

Five thousand seven hundred and nine people aged 18-66 years included in the study, the proportion of men and women was 68.17% and 31.83%, respectively. The average age of the participants was 35.7 ± 10.57 years. The prevalence of anti-HBcore among donors was 17.2% (983). Among participants with elevated ALT (170), this marker was determined in 23%, and for donors with normal levels of ALT (5539)-17%. Participants with positive anti-HBcore scores were on average older (41.8 vs. 34.4 years, p < .001) and Kazakhs (88.7% vs. 83.0%, p < .001) by nationality than study participants with negative results of anti-HBcore.

CONCLUSIONS

Anti-HBcore prevalence in Kazakhstan (17.2%) compared with other countries (Croatia 7%, France 7%, Germany 9%, Iran 16%, Malaysia 20%, respectively) remains above average. Given the prevalence of HBV and risk factors, it is recommended to include an additional anti-HBcore marker in the mandatory screening of donated blood in the Kazakhstan Republic and improve preventive measures to prevent HBV transmission by blood transfusions.

Molecular mechanisms underlying HBsAg negativity in occult HBV infection

Although genomic detection is considered the gold standard test on HBV infection identification, the HBsAg investigation is still the most frequent clinical laboratory request to diagnose HBV infection in activity. However, the non-detection of HBsAg in the bloodstream of chronic or acutely infected individuals has been a phenomenon often observed in clinical practice, despite the high sensitivity and specificity of screening assays standardized commercially and adopted in routine. The expansion of knowledge about the hepatitis B virus biology (replication/life cycle, genetic variability/mutability/heterogeneity), their biochemical and immunological properties (antigenicity and immunogenicity), in turn, has allowed to elucidate some mechanisms that may explain the occurrence of this phenomenon. Therefore, the negativity for HBsAg during the acute or chronic infection course may become a fragile or at least questionable result. This manuscript discusses some mechanisms that could explain the negativity for HBsAg in a serological profile of individuals with HBV infection in activity, or factors that could compromise its detection in the bloodstream during HBV infection.