Virological Characteristics of Acute Hepatitis B in Eastern India: Critical Differences with Chronic Infection

Molecular and genetic characterization of the hepatitis B virus full-length genome sequences identified in HBsAg-negative blood donors in Ural Federal District

Introduction. The World Health Organization estimates that as of 2019, more than 296 million people were living with chronic hepatitis B virus (HBV) infection. The prevalence of HBsAg-negative, occult form of the disease in blood donors varies depending on the region of the world and the sensitivity of the methods of analysis used. Considering that the genetic diversity of viruses demonstrates space and time variations and taking into account that the genetic profile of isolates in key groups, which may turn into a source of the pathogen spread, is important for forecasting of the epidemiological situation, the attention should be given to identification of HBV genotypes currently circulating among regular blood donors in regions of the Russian Federation. The aim of this work was molecular and genetic characterization of HBV genomes identified in HBsAg-negative blood donors in the Ural Federal District. Materials and methods. The study material was 1400 plasma samples obtained from HBsAg-negative blood donors in Ural Federal District. The study included the testing for HBsAg, anti-HBs IgG and anti-HBcore IgG antibodies, HBV DNA. For all identified HBV DNA containing samples, sequencing and analysis of the nucleotide sequences of the complete HBV genomes were performed. Results. The prevalence of HBV DNA was 4.93%, including 4 (0.28%) cases of false occult hepatitis B. Among anti-HBcore IgG-positive samples, HBV DNA was found in 18.08% of cases, while in persons with detected HBV DNA the anti-HBcore IgG positivity rate was 46.38%. In 8.69% of the isolates, anti-HBs IgG antibodies and viral DNA were detected simultaneously in the absence of anti-HBcore IgG. Based on phylogenetic analysis, HBV subgenotypes distribution in HBsAg-negative blood donors was as follows: D3 53.62%, D2 21.74%, D1 18.84%, C2 5.8%. The high variability in the S, C, P regions of the virus genome in the examined group was shown. In all cases of HBsAg-negative chronic HBV infection identified in blood donors, viral sequences contained at least one amino acid substitution in positions, mutations in which are associated with immune escape. In 3 (4.35%) cases mutations in reverse transcriptase region of P gene that are associated with resistance to the following drugs were identified: lamivudine, telbivudine, entecavir. Mutations in the preCore/Core regions that contribute to the progression of liver disease were also identified. Conclusion. Occult HBsAg-negative chronic HBV infection poses a threat of HBV transmission through transfusion of blood and its components due to the extremely low viral load, which does not allow the virus to be detected using routinely used diagnostic kits. The situation can be exacerbated by the abundance and diversity of virus amino acid substitutions that we have identified, including immune escape mutations, drug resistance mutations, and mutations that contribute to the progression of the disease.

Current laboratory tests for diagnosis of hepatitis B virus infection

BACKGROUND

Hepatitis B virus (HBV) has a long history in human infectious diseases. HBV infection can progress chronically, leading to cancer. After introduction of a vaccine, the overall incidence rate of HBV infection has decreased, although it remains a health problem in many countries.

PURPOSE

The aim of this review was to summarise current diagnostic efforts for HBV infection and future HBV diagnosis perspectives.

METHODS

We reviewed and summarised current laboratory diagnosis related with HBV infection in clinical practice.

RESULTS

There have been various serologic- and molecular-based methods to diagnose acute or chronic HBV infection. Since intrahepatic covalently closed circular DNAs (cccDNAs) function as robust HBV replication templates, cure of chronic HBV infection is limited. Recently, new biomarkers such as hepatitis B virus core-related antigen (HBcrAg) and HBV RNA have emerged that appear to reflect intrahepatic cccDNA status. These new biomarkers should be validated before clinical usage.

CONCLUSION

An effective diagnostic approach and current updated knowledge of treatment response monitoring are important for HBV infection management. Brand new ultrasensitive and accurate immunologic methods may pave the way to manage HBV infection in parallel with immunotherapy era.

Interpretation of HBV Serologies

Hepatitis B was discovered by researchers who were investigating jaundice associated with blood transfusions as well as parenterally administered medications. Through trial and error, the HBV was identified. There are specific tests that detect HBV infection, whether it is a previous exposure or active infection. The various HBV serologies are reviewed in this work as well. Hepatitis B surface antigen has emerged as a tool in defining treatment endpoint and its significance is reviewed. HBV genotypes are distributed uniquely throughout the world, in particular, genotype C is associated with higher rates of hepatocellular carcinoma. Various HBV genotypes and their impact on the clinical course are discussed. The relationship of HBV serologies and HBV DNA to disease progression is outlined. There are specific recommendations on monitoring those infected with HBV and this is reviewed here. HBV mutations have an impact on the disease course and those of significance are also discussed.

Case Report: Application of hepatitis B virus (HBV) deep sequencing to distinguish between acute and chronic infection

Deep sequencing of the full-length hepatitis B virus (HBV) genome provides the opportunity to determine the extent to which viral diversity, genotype, polymorphisms, insertions and deletions may influence presentation and outcomes of disease. Increasing experience with analysis of HBV genomic data opens up the potential for using these data to inform insights into pathophysiology of infection and to underpin decision making in clinical practice. We here set out to undertake whole genome HBV sequencing from an adult who presented acutely unwell with a new diagnosis of HBV infection, and tested positive for both HBV anti-core IgM and IgG, possibly representing either acute hepatitis B infection (AHB) or chronic hepatitis B with an acute reactivation (CHB-AR). The distinction between these two scenarios may be important in predicting prognosis and underpinning treatment decisions, but can be challenging based on routine laboratory tests. Through application of deep whole-genome sequencing we typed the isolate as genotype-D1, and identified several minority variants including G1764A and G1986A substitutions in the pre-core promoter and pre-core regions, which support CHB-AR rather than AHB. In the longer term, enhanced deep sequencing data for HBV may provide improved evidence to distinguish between acute and chronic infection, to predict outcomes and to stratify treatment.

Dynamic profile of the HBeAg-anti-HBe system in acute and chronic hepatitis B virus infection: A clinical-laboratory approach

Wild-type HBV infection is followed by the blood expression of its widely known serological markers of infection, and designated as, hepatitis B virus surface antigen (HBsAg) and its antibody (anti-HBs), anti-HBc antibodies (IgM/IgG), and hepatitis B virus 'e' antigen (HBeAg) and its antibody (anti-HBe). These markers are detected as the infection develops and its kinetic behavior serves as a basis for monitoring the disorder and for diagnosing the clinical form or infection phase. Among these, the HBeAg-anti-HBe system markers demonstrate a dynamic profile whose interpretation, both in the acute or chronic HBV infection context, can offer greater difficulty to the health professionals, due to its particularities. This review offers a revisit to the markers dynamics of this system in the acute and chronic HBV infection and to the clinical and laboratory significance of its expression in these two clinical contexts.

Cytokine, Genotype, and Viral Load Profile in the Acute and Chronic Hepatitis B

Several hepatitis B virus (HBV) factors, including viral load, genotype, genome mutations, and cytokine production, have been reported to be associated with different risks of progression of liver disease. The aim of this study was to verify if there is an association among the levels of cytokines (interleukin [IL]-35, IL-6, IL-17A, interferon [IFN]-γ) in the plasma, viral load, and the different genotypes of HBV in patients with acute or chronic hepatitis B. Methods: 49 serum samples, 20 from acute and 29 from chronic cases, were submitted to a real-time and nested-polymerase chain reaction to quantify, detect, and genotype HBV DNA. The cytokines IL-35, IL-6, IL-17A, and IFN-γ were detected by an enzyme-linked immunosorbent assay (ELISA). The median viral load was 3.15 log₁₀ IU DNA/mL and 2.90 log₁₀ IU DNA/mL for acute and chronic patients, respectively. Genotype A, D, E, and F were identified in chronic carriers of HBV infection, while only genotype A and F were identified in individuals with acute infection. IFN-γ (p = 0.024) and IL-17A (p = 0.046) levels were significantly increased in chronic patients and IL-6 and IL-35 were higher in patients with acute infection, however, without statistical difference. IL-17A and IFN-γ can be modulating proinflammatory effects and inducing hepatocellular damage, in chronic patients, and IL-6 and IL-35 may be involved in viral elimination and protection against chronicity during the acute phase of infection. These results can contribute to understanding of the complex regulatory mechanisms of the host antiviral response related to cytokine production during acute and chronic HBV infection.

Case Report: Application of hepatitis B virus (HBV) deep sequencing to distinguish between acute and chronic infection

Deep sequencing of the full-length hepatitis B virus (HBV) genome provides the opportunity to determine the extent to which viral diversity, genotype, polymorphisms, insertions and deletions may influence presentation and outcomes of disease. Increasing experience with analysis of HBV genomic data opens up the potential for using these data to inform insights into pathophysiology of infection and to underpin decision making in clinical practice. We here set out to undertake whole genome HBV sequencing from an adult who presented acutely unwell with a new diagnosis of HBV infection, and tested positive for both HBV anti-core IgM and IgG, possibly representing either acute hepatitis B infection (AHB) or chronic hepatitis B with an acute reactivation (CHB-AR). The distinction between these two scenarios may be important in predicting prognosis and underpinning treatment decisions, but can be challenging based on routine laboratory tests. Through application of deep whole-genome sequencing we typed the isolate as genotype-D1, and identified several minority variants including G1764A and G1986A substitutions in the pre-core promoter and pre-core regions, which support CHB-AR rather than AHB. In the longer term, enhanced deep sequencing data for HBV may provide improved evidence to distinguish between acute and chronic infection, to predict outcomes and to stratify treatment.

A 79-year-old Woman with Acute Hepatitis B Caused by the Infection of Subgenotype D1 Hepatitis B Virus in Japan: A Case Study

A 79-year-old Japanese woman was diagnosed with acute hepatitis B based on laboratory tests showing positivity for IgM-class antibody against hepatitis B virus (HBV) core and hepatitis B surface antigen (HBsAg) as well as elevated transaminases. A phylogenetic analysis revealed that the HBV strain obtained from the patient belonged to genotype D/subgenotype D1, similar to strains circulating in foreign countries but different from those in Japan. The clinical course was favorable. HBsAg became negative within 10 weeks after the onset. To our knowledge, this is the first report of acute hepatitis B caused by subgenotype D1 HBV in Japan.

Distinctiveness in virological features and pathogenic potentials of subgenotypes D1, D2, D3 and D5 of Hepatitis B virus

Distinct clinical features of HBV infection have been associated with different viral genotype/subgenotype. HBV Genotype-D comprised of 10 subgenotypes, D1–D10, whose clinical implications still remain elusive. We investigated for the first-time, the virologic characteristics and cytopathic effects of four non-recombinant D-subgenotypes, D1/D2/D3/D5. Expressions of viral/host genes were evaluated in Huh7 cells transfected with full-length, linear-monomers of HBV/D-subgenotypes or pGL3-Basic vector carrying subgenotype-specific HBx. Intracellular HBV-DNA and pregenomic-RNA levels were high in D1/D2 than D3/D5. Expressions of PreC-mRNA and HBx were highest for D2 and D1 respectively, whereas PreS2/S-transcript was significantly reduced in D5. Increased apoptotic cell death and marked upregulation in caspase-3/Bax/TNF-R1/FasR/TRAIL-R1/ROS/MCP-1/IP-10/MIP-1β expression were noticed specifically in D2- and also in D3-transfected cells, while D5 resulted in over-expression of ER-stress-markers. D-subgenotype-transfected Huh7 cells were co-cultured with PBMC of healthy-donors or LX-2 cells and significant increase in pro-inflammatory cytokines in PBMC and fibrogenic-markers in LX-2 were noticed in presence of D2/D3. Further, Huh7 cells transfected with D1, in particular and also D5, displayed remarkable induction of EMT-markers and high proliferative/migratory abilities. Collectively, our results demonstrated that D2/D3 were more associated with hepatic apoptosis/inflammation/fibrosis and D1/D5 with increased risk of hepatocarcinogenesis and emphasize the need for determining HBV-subgenotype in clinical practice.

Genotyping of hepatitis B virus isolates from Lahaul and Spiti district in Himachal Pradesh, India

Hepatitis B virus (HBV) has several genotypes. In the Indian population, genotypes A and D are the most frequent. HBV infection is hyper-endemic in the Lahaul and Spiti district in Himachal Pradesh; however, the virus genotype in this area is not known. We sequenced a 398-nucleotide segment of HBV genome that included parts of pre-S1/S2 and polymerase genes from 17 specimens from this district, and assigned a viral genotype to these. Of the 17 specimens studied, 13 (76% [95% confidence interval = 50-92%]) showed the presence of genotype C HBV; the remaining four were genotype D (n = 4; 24%) HBV. Prevalence of genotype C HBV was much higher in the district than in other parts of India. This may reflect the historical mixing of this population with that in China. Since genotype C has a higher risk of chronicity and mother-to-child transmission, prevention of HBV infection may need particular emphasis in this area.

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.

Natural history of acute and chronic hepatitis B: The role of HBV genotypes and mutants

Molecular epidemiologic studies reveal remarkable differences in the geographical distribution of hepatitis B virus (HBV) genotypes. The frequency of mutants among HBV genotypes also varies. The role of HBV genotypes/mutants in the pathogenesis of HBV infection and natural history of HBV infection has been extensively investigated. The distribution of HBV genotypes in acute hepatitis B patients reflects the predominant genotypes in a given geographic area. In chronic hepatitis B patients, genotype C and D have a higher frequency of basal core promoter A1762T/G1764A mutations than genotype A and B. HBV genotypes C, D and F carry a higher lifetime risk of cirrhosis and HCC development than genotype A and B. HBV pre-S/S gene mutations were associated with immune escape of hepatitis B immunoglobulin or vaccine-induced immunity. Mutations in the pre-S, core promoter and X regions correlate with an increased risk of cirrhosis and HCC. In summary, HBV genotypes and mutants are associated with the disease progression and long-term outcome of HBV infection. They may serve as viral genetic markers for risk stratification of chronic hepatitis B patients in clinical practice.