Hepatitis B virus genotype, HBsAg mutations and co-infection with HCV in occult HBV infection

Prevalence of hepatitis B infection in the Gambian population: A narrative review of recent developments

Hepatitis B is a "silent epidemic", fifty to a hundred (50-100) times more infectious than HIV, a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). HBV can cause acute and chronic infection and subsequently results in a high risk of death from cirrhosis and liver cancer. Despite the availability of a safe and effective vaccine, HBV continues to be a global burden including in The Gambia. This study reviewed the recent trends in the epidemiological characteristics of HBV in the Gambia. The researchers conducted an online literature search for primary studies on HBV prevalence published in the past two decades from Jan 1992 to Feb 2022 inclusive on Google Scholar, PubMed, and Scopus. All retrieved studies were assessed for eligibility according to specific inclusion/exclusion criteria, data completeness, and methodological coherence. We found that HBV infection prevalence is above 8% in The Gambia. Moreover, HBV is the most common cause of hepatocellular carcinoma (HCC) in Gambia. Liver cirrhosis and HCC have the highest mortality contribution among hepatitis patients, with occult HBV carriers as major culprits. Also, vaccination coverage has declined from 91% to 88% according to reports from current literature. To achieve the WHO goal of eliminating HBV by 2030, policies targeting infection transmission control among risk groups, community awareness programs, research, price reduction of drugs, mass vaccinations, and diagnostics should be urgently instituted.

A Recent Prevalence of Hepatitis B Virus (HBV) Genotypes and Subtypes in Asia: A Systematic Review and Meta-Analysis

Background and Aim: Despite introducing the hepatitis B virus (HBV) vaccine, the incidence of the Hepatitis B virus globally is still a major health concern. This systematic review and meta-analysis were conducted to provide detailed information on the prevalence of HBV genotypes and subtypes in circulation in Asia. Methods: A systematic search for articles describing the prevalence of HBV genotypes and subtypes in Asia was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Our search returned 207 eligible articles involving 49,279 genotypes and 7457 subtypes representing 28 Asian countries. A meta-analysis was performed on our eligible studies using the Random effect Model. The pooled prevalence of HBV genotypes showed that genotype C (30.9%) (95% CI, 27.5–34.5%; I2 = 97.57%; p < 0.001) was the most common HBV genotype in Asia, followed by genotype B (17.8%) (95% CI, 15.5–20.4%; I2 = 97.26%; p < 0.001) and genotype D (15.4%) (95% CI, 11.8–19.8%). Vietnam had the highest prevalence of genotype B, Lebanon had the highest prevalence of genotypes C, and Jordan had the highest prevalence of genotype D. There was variation in genotypic prevalence with respect to the target genes for HBV genotyping. Reverse dot blot hybridization had the highest estimate of genotypes B and C. HBV subtype C2 (40.0%) (95% CI, 33.3–47.0) is the most prevalent HBV subtype. Conclusion: Evidence from this study reveals that HBV genotypes C and B are the most dominant HBV genotypes in Asia, and HBV subtype C2 is more endemic in Asia.

Rapid detection of hepatitis B virus in blood plasma by a specific and sensitive loop-mediated isothermal amplification assay

BACKGROUND

Hepatitis B virus (HBV) is an important blood-borne pathogen that causes hepatic inflammation and can lead to liver cirrhosis and hepatocellular carcinoma. Conventional methods of HBV detection are time consuming and require highly trained personnel and elaborate equipment. This report describes the development of a rapid, simple, specific, and sensitive loop-mediated isothermal amplification assay (LAMP) for detection of HBV genotypes A, B, C, D, E, and F in blood samples.

METHODS

HBV standard plasma panels and clinical donor plasma specimens were used for the development and validation of the LAMP assay. Amplification was performed at 60°C for 60 minutes using extracted DNA or heat-treated plasma specimens without DNA extraction. The assay was evaluated for its ability to detect various HBV genotypes and for its sensitivity, specificity, and time-point of detection.

RESULTS

The LAMP assay detected HBV genotypes A-F and demonstrated a sensitivity of 10-100 IU per reaction of HBV DNA. The assay also detected 69 of 75 (92%) HBV-positive donor plasma specimens tested and demonstrated a specificity of 100%.

CONCLUSIONS

These results demonstrate that our HBV-LAMP assay is rapid, sensitive and specific, and capable of detecting the major HBV genotypes. This assay could be used in clinical point-of-care settings, mainly in endemic and resource-limited environments for HBV diagnostics, donor screening, epidemiological studies, and therapeutic monitoring of patients undergoing antiviral treatment.

Intensity of HLA-A2 Expression Significantly Decreased in Occult Hepatitis B Infection

Background:

Occult hepatitis B infected (OBI) patients cannot eradicate hepatitis B virus (HBV)-DNA from their liver and peripheral blood, completely.

Objectives:

The main aim of this study was to investigate the rate of HLA-A2 expression on peripheral blood mononuclear cells (PBMCs) of patients with OBI.

Materials and Methods:

In this experimental study, intensity of HLA-A2 was measured on the PBMCs of 57 OBI patients and 100 HBsAg-/anti-HBc+/HBV-DNA samples were enrolled as controls; measurements were performed using the flow cytometry technique.

Results:

Flow cytometric analysis indicated that 19 (33.3%) OBI patients and 28 (28%) controls expressed HLA-A2 antigen on their PBMCs. There was no significant difference between the two groups regarding the rate of individuals expressing HLA-A2 antigen. Statistical analyses showed that the intensity of HLA-A2 expression significantly decreased in OBI patients (3.58 ± 0.1) in comparison to healthy controls (4.21 ± 0.25; P < 0.001).

Conclusions:

According to these results it can be concluded that decreased intensity of HLA-A2 on the PBMCs of OBI patients may lead to resistance of HBV in the patients.

Occult hepatitis B infection in the immigrant population of Sicily, Italy

In Italy, about 7 % of the resident population is represented by immigrants originating from geographic regions at high endemicity for hepatitis B virus infection. This study aims to assess the prevalence of occult HBV infection (OBI) including the identification of HBV-genotypes in a population of immigrants serologically negative for hepatitis B surface antigen (HBsAg). Between May 2006 and May 2010, 339 immigrants were tested for markers of HBV, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. HBV-DNA was tested by using nested-PCR assays on three different genetic region. HBV-DNA was detected in plasma samples of 11/339 (3.2 %) patients. Most of them had no serological markers of HBV infection, 3/58 (5.2 %) were anti-HBc-alone, and 4/13 (30.8 %) were anti-HIV positive. HIV positivity was the only factor independently associated with the higher probability of observing OBI (OR = 16.5, p < 0.001). No HCV co-infected patients were found. Genotype D was detected in 9/11 (81.8 %) OBI cases, while the remaining two (18.2 %) were classified as genotype E. Although OBI was found at lower rate than expected among immigrants from highly endemic countries, anti-HBc alone positivity was confirmed as a sentinel marker of occult HBV infection. Nevertheless, a marked heterogeneity of HBV markers was found among HBV-DNA positive subjects. Our finding evidenced the predominance of HBV-genotype D viral strains among OBI cases, also in those from geographical areas where overt HBV infections are mainly sustained by viral genotypes other than D.

Prevalence of occult hepatitis B virus infection in a cohort of HIV-positive patients resident in Sicily, Italy

Occult hepatitis B virus (OBI) in HIV-infected groups is still debated, as well as the associated risk-factors and clinical significance. In this paper, we examined a total of 405 HBsAg-negative/HIV-infected patients enrolled from January 2007 to December 2009. Overall, the prevalence of OBI was 5.9% (95% confidence interval (CI_95%): 3.8–8.7%); it was more frequently associated with “anti-HBc alone” serological marker (11.3%; adjusted odds ratio = 3.7, CI_95%: 1.4–9.8), although it was also detected in the absence of any HBV serological marker (4.9%; CI_95%: 2.3–9.1%). A low prevalence of anti-HCV-positive patients with OBI was found (3.1%; CI_95%: 0.6–8.7%). HIV RNA plasma levels or other immunological/clinical characteristics were not significantly associated with OBI. All but one occult HBV infections were sustained by genotype D viral strains. OBI is relatively frequent in HIV-infected patients, although it does not seem to exert a relevant clinical impact. Viral genotypes in occult HBV infections reflect those circulating in the Mediterranean area.

Variations in the hepatitis B virus genome and their clinical significance

Hepatitis B virus (HBV) is a hepatotropic DNA virus. The HBV genome is prone to variations. Based on genomic variations, HBV is divided into ten genotypes, many subgenotypes and quasispecies. These genotypes, subgenotypes and quasispecies have distinct race and geographic distribution and have been associated with outcome of HBV infection, disease progression and treatment.