Prevalence and Clinical Significance of Occult Hepatitis B Infection in The Gambia, West Africa.

BACKGROUND: Prevalence and clinical outcomes of occult hepatitis B infection (OBI) have been poorly studied in Africa. METHODS: Using the PROLIFICA cohort, we compared the prevalence of OBI between hepatitis B surface antigen (HBsAg)-negative healthy adults screened from the general population (controls) and HBsAg-negative patients with advanced liver disease (cases), and estimated the population attributable fraction for the effect of OBI on advanced liver disease. RESULTS: OBI prevalence was significantly higher among cases (15/82, 18.3%) than controls (31/330, 9.4%, P = .03). After adjusting for age, sex, and anti-hepatitis C virus (HCV) serology, OBI was significantly associated with advanced liver disease (odds ratio, 2.8; 95% confidence interval [CI], 1.3-6.0; P = .006). In HBsAg-negative people, the proportions of advanced liver disease cases attributable to OBI and HCV were estimated at 12.9% (95% CI, 7.5%-18.1%) and 16.9% (95% CI, 15.2%-18.6%), respectively. CONCLUSIONS: OBI is endemic and an independent risk factor for advanced liver disease in The Gambia, West Africa. This implies that HBsAg-negative people with liver disease should be systematically screened for OBI. Moreover, the impact of infant hepatitis B immunization to prevent end-stage liver disease might be higher than previous estimates based solely on HBsAg positivity.

Hepatitis B virus preS2Δ38-55 variants: A newly identified risk factor for hepatocellular carcinoma.

BACKGROUND & AIMS: Although HBV is a major cause of death in Africa, its genetic variability has been poorly documented. This study aimed to address whether HBV genotype and surface gene variants are associated with HBV-related liver disease in The Gambia. METHODS: We conducted a case-control study nested in the Prevention of Liver Fibrosis and Cancer in Africa programme. Consecutive treatment-naive patients with chronic HBV infection and detectable viral load were recruited: 211 controls with no significant liver disease and 91 cases (56 cirrhosis and 35 HCC cases). HBV genotypes and surface gene variants were determined by Sanger sequencing or next-generation sequencing (NGS) in serum DNA. Aflatoxin B1 (AFB1)-specific codon 249 TP53 mutation was determined by NGS in circulating cell-free plasma DNA. RESULTS: In phylogenetic analysis, 85% of individuals carried HBV genotype E, 14% genotype A, and 1% A/E recombinant viruses. Surface gene variants were more frequently observed in cases (43% and 57% in cirrhosis and HCC cases, respectively) than controls (25%; p <0.001), with preS2 deletions between nucleotides 38-55 (preS2Δ38-55) being the main genetic variant detected. In multivariable analysis, HBeAg seropositivity, low HBsAg levels, and HDV seropositivity were significantly associated with cirrhosis and HCC, whilst older age, higher viral load, genotype A, preS2Δ38-55, and AFB1 exposure were only associated with HCC. There was a multiplicative joint effect of preS2Δ38-55 variants with HBeAg seropositivity (odds ratio [OR] 43.1 [10.4-177.7]), high viral load >2,000 IU/ml (OR 22.7 [8.0-64.9]), HBsAg levels <10,000 IU/ml (OR 19.0 [5.5-65.3]), and AFB1 exposure (OR 29.3 [3.7-230.4]) on HCC risk. CONCLUSIONS: This study identified a hotspot for HBV preS2 deletions as a strong independent factor for HCC in The Gambia, with HBV genotypes and AFB1 exposure contributing to the high liver cancer risk. LAY SUMMARY: Although HBV-related liver disease is highly prevalent in sub-Saharan Africa, the associated virological characteristics are poorly studied. Using clinical data from African patients chronically infected with HBV, an assessment of the virological variability (genotypes and mutations) and exposure to AFB1, a toxin often contaminating food, was carried out. Our results show that HBV genotypes, the presence of a highly prevalent mutant form of HBV, and AFB1 exposure contribute to the high liver cancer risk in this population.

CD8+CD28- T cells: key cytotoxic players impacting disease pathogenesis in chronic HBV infection.

During chronic hepatitis B (CHB), CD8+ T cells down-regulate CD28, the primary co-stimulation molecule for T-cell activation. Diverse functional attributes of CD8+CD28- T cells are suggested in various disease contexts. The present study aimed to characterize CD8+CD28- T cells in different phases of chronic Hepatitis B virus (HBV) infection (CHI)- Immune-tolerance (IT), Hepatitis B e-antigen-positive CHB (EP-CHB), Inactive carriers (IC) and Hepatitis B e-antigen-negative CHB (EN-CHB), to appraise their contribution in HBV-related disease pathophysiology. Flow cytometry analysis of T cells in peripheral blood of study subjects revealed enhanced CD8+CD28- T-cell accumulation in EP-/EN-CHB, compared with IT/IC and they expanded equivalently in HBV-specific and non-specific CD8+ T-cell compartments. Profound increase in CD8+CD28- T cells expressing perforin/granzyme-B/CD57/IFN-γ/TNF-α and markers of terminal differentiation were observed exclusively in EP-/EN-CHB. Further, activation with anti-NKG2D resulted in heightened IFN-γ/TNF-α production selectively from CD8+CD28- T cells, suggesting NKG2D-mediated alternative co-stimulation. CD8+CD28- T cells sorted from CHB patients induced enhanced apoptosis of peripheral blood mononuclear cells (PBMC), including CD4+ T cells. However, NKG2D-ligand (major histocompatibility complex class I chain-related molecule A/B (MICA/B)) was preferentially expressed by HBV-specific CD4+ T cells of CHB patients, making these cells a potential target to NKG2D-dependent CD8+CD28- T-cell killing. Both CD28+ and CD28- T cells in CHB expressed CXCR3 at similar levels and thus capable of homing to the liver. A positive correlation was seen between CD8+CD28- T-cell frequency and serum-alanine transaminase (ALT) levels and CHB-derived CD8+CD28- T cells caused pronounced cell death in HBV-transfected Huh7 cells. Immunofluorescence staining identified greater intrahepatic incidence of CD8+CD28- T cells but decline in CD4+ T cells in CHB than IC. Collectively, CD8+CD28- T cells demonstrated differential distribution and phenotypic/functional skewing in different CHI phases and contribute to disease progression by Perforin-Granzyme- or IFN-γ-TNF-α-mediated cytotoxicity while restraining antiviral immunity through NKG2D-dependent HBV-specific CD4+ T-cell depletion.

[Prevention of liver fibrosis and liver cancer linked to hepatitis B virus in Africa: the Prolifica study]. / Prévention de la fibrose et du cancer du foie liés au virus de l'hépatite B en Afrique - Le projet Prolifica.

Despite the existence of an effective vaccine, HBV infects 257 million people worldwide and is the cause of the majority of HCC. With an annual mortality rate of 887 000 patients in 2015, this cancer is the second deadliest. Low-income countries such as ones in sub-Saharan Africa are the most at risk due to the limited access to healthcare. To overcome this and born from an international research collaboration within an EU project, the Prolifica study aimed at evaluating a screen-and-treat program to prevent HBV complications, and more particularly HCC. Based on communities, facilities and hospitals HBsAg+ detection, the study lasted from 2011 to 2016. From the "cost effectiveness" feasibility of such a program to the development of simple scores for antiviral treatment, Prolifica uncovered data of crucial importance in a region with low HBV infection awareness, transmissions modes and prevention means which could have impacts on public health policies.

Acceptability and feasibility of a screen-and-treat programme for hepatitis B virus infection in The Gambia: the Prevention of Liver Fibrosis and Cancer in Africa (PROLIFICA) study.

BACKGROUND: Despite the introduction of immunisation for hepatitis B virus (HBV) in the 1990s, HBV-related morbidity and mortality remain high in sub-Saharan Africa. Identification and treatment of asymptomatic people with chronic HBV infection should reduce the disease burden. We therefore assessed the feasibility of a screen-and-treat programme for HBV infection in The Gambia, west Africa, and estimated the proportion of HBV-infected people who had significant liver disease in need of treatment. METHODS: Between Dec 7, 2011, and Jan 24, 2014, individuals living in randomly selected communities in western Gambia were offered hepatitis B surface antigen (HBsAg) screening via a point-of-care test. The test was also offered to potential blood donors attending the central hospital in the capital, Banjul. HBsAg-positive individuals were invited for a comprehensive liver assessment and were offered treatment according to international guidelines. We defined linkage to care as visiting the liver clinic at least once. Eligibility for treatment was judged in accordance with the 2012 European Association for the Study of the Liver guidelines. FINDINGS: HBsAg screening was accepted by 5980 (weighted estimate 68·9%, 95% CI 65·0-72·4) of 8170 adults from 27 rural and 27 urban communities and 5559 (81·4%, 80·4-82·3) of 6832 blood donors. HBsAg was detected in 495 (8·8%, 7·9-9·7) individuals in communities and 721 (13·0%, 12·1-13·9) blood donors. Prevalence was higher in men (239 [10·5%, 8·9-12·1] of 2328 men vs 256 [7·6%, 6·5-8·7] of 3652 women; p=0·004) and middle-aged participants. Linkage to care was high in the communities, with 402 (81·3%) of 495 HBsAg-positive individuals attending the clinic. However, only 300 (41·6%) of 721 HBsAg-positive people screened at the blood bank linked into care. Of those who attended the clinic, 18 (4·4%, 2·5-7·7) patients from the communities and 29 (9·7%, 6·8-13·6) from the blood bank were eligible for treatment. Male sex was strongly associated with treatment eligibility (odds ratio 4·35, 1·50-12·58; p=0·007). INTERPRETATION: HBV infection remains highly prevalent in The Gambia. The high coverage of community-based screening, good linkage into care, and the small proportion of HBsAg carriers who need treatment suggest that large-scale screening and treatment programmes are feasible in sub-Saharan Africa. FUNDING: European Commission (FP7).

A rare HBV subgenotype D4 with unique genomic signatures identified in north-eastern India--an emerging clinical challenge?

BACKGROUND/AIMS: HBV has been classified into ten genotypes (A-J) and multiple subgenotypes, some of which strongly influence disease outcome and their distribution also correlate with human migration. HBV infection is highly prevalent in India and its diverse population provides an excellent opportunity to study the distinctiveness of HBV, its evolution and disease biology in variegated ethnic groups. The North-East India, having international frontiers on three sides, is one of the most ethnically and linguistically diverse region of the country. Given the paucity of information on molecular epidemiology of HBV in this region, the study aimed to carry out an in-depth genetic characterization of HBV prevailing in North-East state of Tripura. METHODS: From sera of chronically HBV infected patients biochemical/serological tests, HBV DNA quantification, PCR-amplification, sequencing of PreS/S or full-length HBV genomes were done. HBV genotype/subgenotype determination and sequence variability were assessed by MEGA5-software. The evolutionary divergence times of different HBV subgenotypes were estimated by DNAMLK/PHYLIP program while jpHMM method was used to detect any recombination event in HBV genomes. RESULTS: HBV genotypes D (89.5%), C (6.6%) and A (3.9%) were detected among chronic carriers. While all HBV/A and HBV/C isolates belonged to subgenotype-A1 and C1 respectively, five subgenotypes of HBV/D (D1-D5) were identified including the first detection of rare D4. These non-recombinant Indian D4 (IndD4) formed a distinct phylogenetic clade, had 2.7% nucleotide divergence and recent evolutionary radiation than other global D4. Ten unique amino acids and 9 novel nucleotide substitutions were identified as IndD4 signatures. All IndD4 carried T120 and R129 in ORF-S that may cause immune/vaccine/diagnostic escape and N128 in ORF-P, implicated as compensatory Lamivudine resistance mutation. CONCLUSIONS: IndD4 has potential to undermine vaccination programs or anti-viral therapy and its introduction to North-East India is believed to be linked with the settlement of ancient Tibeto-Burman migrants from East-Asia.

Nonobese population in a developing country has a high prevalence of nonalcoholic fatty liver and significant liver disease.

UNLABELLED: There is a paucity of community-based epidemiological data on nonalcoholic fatty liver (NAFL) among nonaffluent populations in developing countries. Available studies are radiological and/or biochemical and lack histological assessment, limiting their strength. We conducted a prospective epidemiological study comprising a 1:3 subsample of all adult (>18 years) inhabitants of a rural administrative unit of West Bengal, India. Subjects positive for hepatitis B virus and/or hepatitis C virus infection and consuming any amount of alcohol were excluded. Diagnosis of NAFL was by dual radiological screening protocol consisting of ultrasonographic and computed tomographic examination of the liver. Transient elastographic examination and liver biopsy were performed in a subset to identify significant liver disease. The risk factors of having NAFL were analyzed. A total of 1,911 individuals were analyzed, 7% of whom were overweight and 11% of whom had abdominal obesity. The prevalence of NAFL, NAFL with elevated alanine aminotransferase, and cryptogenic cirrhosis was 8.7%, 2.3%, and 0.2%, respectively. Seventy-five percent of NAFL subjects had a body mass index (BMI) <25 kg/m(2), and 54% were neither overweight nor had abdominal obesity. The subjects with the highest risk of having NAFL were those with a BMI >25 kg/m(2) (odds ratio 4.3, 95% confidence interval 1.6-11.5). Abdominal obesity, dysglycemia (fasting plasma glucose >100 mg/dL or elevated homeostatic model assessment of insulin resistance), and higher income were the other risk factors. Even having a normal BMI (18.5-24.9 kg/m(2)) was associated with a 2-fold increased risk of NAFL versus those with a BMI <18.5 kg/m(2). CONCLUSION: There is a significant prevalence of NAFL and potentially significant liver disease, including cryptogenic cirrhosis, in this predominantly nonobese, nonaffluent population in a developing country. NAFL will be a major determinant of future liver disease burden in countries of the developing world.