Prevalence of mutations in basal core promoter and precore region of hepatitis B virus in vaccinated and nonvaccinated individuals of the aboriginal Nicobarese tribe of Car Nicobar Island, India

LCR based quick detection of hotspot G1896A mutation in patients with different spectrum of hepatitis B

G1896A switch is one of the hotspots in subjects affected with hepatitis B. This hotspot mutation is observed in all the different spectrum of hepatitis B, and it has a very dangerous and a long lasting effect. The major purpose of the study was to screen G1986A mutations at a large scale and also to establish ligase chain reaction as a mutation testing tool. Polymerase chain reaction (PCR) and Nucleotide Sequencing was done to identify the G1896A mutation in the precore region of the genome. All the 331 HBV positive patients were screened. Almost 29% (24/82) of the cases remarkably had the presence of G1896A mutation confirmed by LCR and direct sequencing. The precore G1896A mutation is responsible for one third of the patients suffering from precore stop codon mutation. It clearly exhibits that LCR is 100% in sync with direct sequencing and is extremely reliable and the results are highly reproducible.

Molecular characterization of hepatitis B virus reveals circulation of multiple subgenotypes of genotype D with clinically important mutations in central India

PURPOSE

Hepatitis B virus (HBV) is one of the leading causes of morbidity and mortality across the globe. The pathogenesis, clinical outcomes, disease progression and response to antiviral treatment of HBV depend on infecting genotypes and mutations across HBV genome. There is a lack of such information from central India. The present study was planned to identify genotype/subgenotype and epidemiologically important mutation in HBV circulating in the area.

METHODS

Samples positive for HBsAg by ELISA from 2012 to 2016 were included and analysed in this retrospective study. The amplification of partial S gene (n = 25) and full genome (n = 10) was carried out to determine the genotype/subgenotype and genome wide mutations of HBV. The sequencing data was analysed using bioinformatics tools.

RESULTS

All 25 sequences belonged to genotype D; subgenotypes D1, D2, D3 and D5 with dominance of D1 were detected in the study subjects. Mutational profiling revealed the presence of nucleotide substitutions in promoter/regulatory/precore region associated with liver disease progressions. The amino acid (aa) changes associated with vaccine escape, immune escape, antiviral resistance and progression to liver cirrhosis (LC) or hepatocellular carcinoma (HCC) were detected.

CONCLUSIONS

This maiden molecular study on HBV from central India indicates that the genotype D with subgenotypes D1, D2, D3 and D5 harbouring mutations of clinical and epidemiological importance are in circulation. This study will serve as a baseline for future. Studies with larger sample size may aid in identifying the circulation of more genotypes.

Current Scenario of Hepatitis B and Its Treatment in India

Hepatitis B is a significant public health problem in India, yet disease awareness is very low among the general population. The disease is mostly acquired horizontally, but the role of vertical transmission should not be underestimated. In spite of the fact that the majority of cases are e negative disease, most patients present in the advanced stage and even with hepatocellular carcinoma, the leading cause of which is hepatitis B. High-risk groups (especially tribals) also harbour significant disease burden and have a high prevalence of occult infection, supporting the potential of unknowingly spreading the disease. Findings on the relation of genotypes with disease severity or drug action have been conflicting. Though recently, oral antivirals with high genetic barrier to resistance have shown good viral suppression in the long term, e and s seroconversion is poor and relapse is universal upon therapy discontinuation. As no cure is possible with the currently available therapy, the target is long-term viral suppression by prolonged administration of oral antivirals; unfortunately, this leads to poor treatment adherence, which along with the high cost of therapy results in disease progression and spread of infection. At present, therefore, emphasis should be put on health education of the general and high-risk populations, along with health care workers to increase knowledge on such preventive measures as avoiding unsafe injection practices, high-risk sex, performing unnecessary injection and blood transfusion and providing proper screening of blood products; these efforts should be combined with intensive screening and aggressive vaccination programs, especially in high-risk groups and areas of high endemicity. Vaccination strategies are still below par and logistics should be developed for wider coverage; in addition, further research should be carried out on the efficacy and mode of usage for different types of vaccine.

Hepatitis B virus precore G1896A mutation in chronic liver disease patients with HBeAg negative serology from North India

Hepatitis B with precore stop codon mutation is related with severe liver damage in HBeAg negative patients. It is of utmost importance to screen the G1896A precore mutation. The study was designed to assess the impact of G1986A mutations in patients with different clinical spectra of the liver disease by PCR–LCR. 210 HBV positive patients with HBeAg negative serology of different kind of liver diseases (AVH = 72, FH = 21, CH = 79, Cirrhosis = 20 and HCC = 18) were screened. Patients were screened for the presence or absence of precore G1896A mutation by PCR–LCR. Direct nucleotide sequencing was done to confirm the results of LCR. Precore mutant in HCC was 94.4% (17/18), 85.7% (18/21) in FH, 60% (12/20) in liver cirrhosis, 48.1% (38/79) in chronic hepatitis and 27.7% (20/72) in AVH cases. The serum ALT level was statistically significant between HBeAg negative WT and G1896A mutants in chronic hepatitis cases. ALT level and HBV DNA level was slightly raised in the pre core mutant but and was not significant. Genotype D had a higher prevalence (79.5%) as compared to genotype A (20.5%). The mutations detected by PCR–LCR were in 100% concordance with direct sequencing. The exceptionally high prevalence of G1896A in FH and HCC demonstrates that the precore mutants are strongly associated with the progression of liver diseases in patients with HBeAg negative serology. The findings are also suggestive of screening HBV precore G1896A mutation particularly in HBeAg negative cases. The precore G1896A mutation increases proportionately in severe form of liver diseases. LCR can be a suitable tool for screening of G1896A mutations.