Occult hepatitis B virus infection in patients with chronic hepatitis C treated with antiviral therapy

Prevalence of occult hepatitis B virus infection in Egypt: a systematic review with meta-analysis

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is a major public health problem. The clinical importance of OBI stems from the fact that it can be transmitted to healthy individuals at extremely low viral load levels. Additionally, immunosuppression has the potential to trigger viral replication, which can result in life-threatening liver decompensation. Despite several studies examining the prevalence of OBI, the pooled prevalence of OBI in Egypt remains unknown, particularly among blood donors and high-risk individuals, to whom intervention should be targeted.

METHODS

A comprehensive literature search of the following databases was conducted from inception to October 2022 using the following keywords: occult hepatitis B virus infection or occult HBV infection or OBI and Egypt in MEDLINE [PubMed], Scopus, Google Scholar, and Web of Science. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. I-squared and Cochran's Q were used to measure the heterogeneity between the studies, and based on the random effects model, results were reported as proportions (%) with a 95% confidence interval (CI). Analyses of subgroup analyses were conducted based on the target population. Sensitivity analyses were conducted using the leave-one-out approach to test the robustness of the results.

RESULTS

A total of 50 studies with 62 estimations of OBI were included, 19 in patients who were HBsAg-negative and anti-HBc-positive and 43 in patients who were HBsAg-negative. The highest prevalence (41%) was among multi-transfused patients according to  studies that report occult hepatitis B virus prevalence in an HBsAg-negative population, while the pooled prevalence of OBI among patients on hemodialysis, patients with chronic hepatitis C infection, patients with hepatocellular carcinoma (HCC), and patients with liver cirrhosis was 17%, 10%, 24%, and 13%, respectively. On the other hand, among studies that report OBI prevalence in HBsAg-negative and anti-HBc-positive individuals, the pooled prevalence of OBI among blood donors, patients with chronic hepatitis C infection, and patients with HCC was 12%, 15%, and 31%, respectively. Also, the majority of studies examining the genetic background of OBI have found that genotype D is the most prevalent.

CONCLUSION

 This study highlights the high prevalence in OBI among blood donors and high-risk populations in Egypt. The implementation of HBV nucleic acid amplification testing (NAT) may increase the safety of blood transfusions by excluding all HBV DNA-positive donations. However, the cost-effectiveness of these tests should be investigated.

Prevalence of occult HBV infection in Western countries

Due to a lack of standardized tests, it is difficult to obtain prevalence data and define the real impact of occult HBV infection (OBI) in Western countries. The present review article addresses the prevalence of OBI, defined as presence of hepatitis B virus (HBV) DNA in liver tissue or plasma in HBsAg-negative subjects, in Western countries. This varies in different studies according to the different methodologies used (based on serology vs virology), to the sample analyzed for the diagnosis (liver tissue vs plasma), to the different populations studied, to the different geographical variations in the HBV spread, to the host characteristics (age, gender, risk factors for acquiring HBV infection) and to the presence of other parenteral infections (hepatitis C virus and/or human immunodeficiency virus [HIV] infections). Considering the different liver diseases analyzed, that is in patients with cryptogenic cirrhosis or advanced liver fibrosis, the prevalence of OBI ranges 4% to 38%. Considering the different populations studied, in the case of parenteral blood exposure it is about 45%, in patients with chronic hepatitis C it is estimated at about 52%, in HIV-infected patients it ranges from 0% to 45%, in blood donors from 0% to 22.7% and in hemodialysis patients it ranges from 0% to 54%. In conclusion, OBI is a virological entity to be considered when performing the patient's evaluation for immunosuppressive diseases, liver pathologies, or for blood transfusions. Knowing the prevalence and clinical impact of OBI will allow better patient management.

An estimation of the prevalence of occult HBV infection in Western Europe and in Northern America: A meta-analysis

Data on the prevalence of occult HBV infection (OBI) in Western Europe and in Northern America are few; hence, we conducted a systematic review and meta-analysis. All studies included had to fulfil the following inclusion criteria: (a) they investigated the prevalence of OBI (HBV DNA in liver tissue in HBsAg-negative subjects), (b) were carried out in Western Europe and in Northern America; (c) were available as a full-text manuscript, (d) written in English and (e) published up to December 2018. The exclusion criteria were as follows: (a) meta-analyses, letters, reviews, meeting abstracts or editorial comments; (b) studies investigating HBsAg-positive patients; (c) those investigating OBI outside Western Europe and in Northern America; and (d) to avoid small sample bias in the random-effects model, those enrolling less than five subjects. Thirty-four studies met the inclusion criteria, allowing a meta-analysis on 2729 patients. The overall prevalence of OBI was 34% (95% CI = 26%-42%), 28% (CI 95%: 12%-48%) in 329 subjects without chronic liver disease and 35% (95% CI 26%-44%) in 2400 patients with chronic liver disease. The prevalence of OBI was 51% (95% CI 40%-62%) in the 823 anti-HBc-positive subjects and 19% (95% CI 10%-30%) in the 1,041 anti-HBc-negative subjects. Evaluating the data from 17 studies comparing anti-HBc-positive and negative subjects, the prevalence of OBI was higher in the 641 anti-HBc-positive subjects than in the 1041 anti-HBc-negative (prevalence ratio = 2.29; 95% CI = 1.61-3.26, P < .001). This meta-analysis showed that in HBsAg-negative subjects the prevalence of OBI was high and was associated with anti-HBc positivity.

Evaluation of impact of occult hepatitis B infection in chronic HCV-infected patients: A retrospective cohort study

CONTEXT

Occult hepatitis B infection (OBI) may contribute to liver damage and variable therapeutic response in patients with chronic hepatitis C (CHC) infection.

AIMS

To study the prevalence of OBI and to evaluate its impact and/or that of anti-HBc total seropositivity on clinical outcomes and response to directly acting antiviral (DAA) therapy in CHC-infected patients.

SETTINGS AND DESIGN

A retrospective cohort study was conducted in a tertiary care liver hospital from January to May 2017.

SUBJECTS AND METHODS

Eighty HBsAg-negative CHC patients who were initiated on DAA therapy were retrospectively included. Archived pretreatment baseline plasma samples were retrieved and tested for quantitative HBV DNA, anti-HBs, and anti-HBc total antibodies. HCV RNA, genotype, clinical, biochemical and histopathological parameters & treatment response data were obtained from the hospital information system.

STATISTICAL ANALYSIS USED

Comparison of continuous variables was done by Mann-Whitney and Kruskal-Wallis tests and categorical variables by Fisher's exact test or Pearson's Chi-square test.

RESULTS

Prevalence of OBI was 1.25%. Anti-HBc total positivity was seen in 25% patients. Based on anti-HBc total status, patients were categorized into two groups namely Group 1 (anti-HBc positive) and Group 2 (anti-HBc negative). Group 1 patients were further categorized into three subgroups based on signal/cutoff (S/Co) of HBc total antibody semi-quantitative values. HBc total antibody levels did not influence the severity of CHC disease. Comparative evaluation of parameters such as median log₁₀ baseline RNA (P = 0.929 and 0.464), median alanine aminotransferase (ALT 0) (P = 0.519 and 0.449), ALT at 12 weeks (P = 0.875 and 0.594), sustained virological response (SVR) at 12 weeks (P = 0.405 and 0.263) and SVR at 24 weeks (P = 0.265 and 0.625) between Groups 1 and 2 and among three categories within Group 1, respectively, were not found to be statistically significant.

CONCLUSIONS

Very low prevalence of OBI was seen in CHC patients. HBc total antibody levels did not influence clinical outcome and response to DAA therapy in this cohort.

Quantitation of HBV cccDNA in anti-HBc-positive liver donors by droplet digital PCR: A new tool to detect occult infection

BACKGROUND & AIMS

The accurate diagnosis of occult hepatitis B virus (HBV) infection (OBI) requires the demonstration of HBV DNA in liver biopsies of hepatitis B surface antigen-negative individuals. However, in clinical practice a latent OBI is deduced by the finding of the antibody to the hepatitis B core antigen (anti-HBc). We investigated the true prevalence of OBI and the molecular features of intrahepatic HBV in anti-HBc-positive individuals.

METHODS

The livers of 100 transplant donors (median age 68.2 years; 64 males, 36 females) positive for anti-HBc at standard serologic testing, were examined for total HBV DNA by nested-PCR and for the HBV covalently closed circular DNA (HBV cccDNA) with an in-house droplet digital PCR assay (ddPCR) (Linearity: R2 = 0.9998; lower limit of quantitation and detection of 2.4 and 0.8 copies/105 cells, respectively).

RESULTS

A total of 52% (52/100) of the individuals studied were found to have OBI. cccDNA was found in 52% (27/52) of the OBI-positive, with a median 13 copies/105 cells (95% CI 5-25). Using an assay specific for anti-HBc of IgG class, the median antibody level was significantly higher in HBV cccDNA-positive than negative donors (17.0 [7.0-39.2] vs. 5.7 [3.6-9.7] cut-off index [COI], respectively, p = 0.007). By multivariate analysis, an anti-HBc IgG value above 4.4 COI was associated with the finding of intrahepatic HBV cccDNA (odds ratio 8.516, p = 0.009); a lower value ruled out its presence with a negative predictive value of 94.6%.

CONCLUSIONS

With a new in-house ddPCR-based method, intrahepatic HBV cccDNA was detectable in quantifiable levels in about half of the OBI cases examined. The titer of anti-HBc IgG may be a useful surrogate to predict the risk of OBI reactivation in immunosuppressed patients.

LAY SUMMARY

The covalently closed circular DNA (cccDNA) form of the hepatitis B virus (HBV) sustains the persistence of the virus even decades after resolution of the symptomatic infection (occult HBV infection). In the present study we developed a highly sensitive method based on droplet digital PCR technology for the detection and quantitation of HBV cccDNA in the liver of individuals with occult HBV infection. We observed that the amount of HBV cccDNA may be inferred from the titer in serum of the IgG class antibody to the hepatitis B core antigen. The quantitation of this antibody may represent a surrogate to determine which patients are at the highest risk of HBV reactivation following immunosuppressive therapies.

Prediction of occult hepatitis B virus infection in liver transplant donors through hepatitis B virus blood markers

BACKGROUND

Occult hepatitis B virus infection is defined as detectable HBV-DNA in liver of HBsAg-negative individuals, with or without detectable serum HBV-DNA. In deceased liver donors, results of tissue analysis cannot be obtained prior to allocation for liver transplantation.

AIMS

we investigated prevalence and predictability of occult hepatitis B using blood markers of viral exposure/infection in deceased liver donors.

METHODS

In 50 consecutive HBsAg-negative/anti-HBc-positive and 20 age-matched HBsAg-negative/anti-HBc-negative donors, a nested-PCR assay was employed in liver biopsies for diagnosis of occult hepatitis B according to Taormina criteria. All donors were characterized for plasma HBV-DNA and serum anti-HBs/anti-HBe.

RESULTS

In liver tissue, occult hepatitis B was present in 30/50 anti-HBc-positive (60%) and in 0/20 anti-HBc-negative donors (p<0.0001). All anti-HBc-positive donors with detectable HBV-DNA in plasma (n=5) or anti-HBs>1,000 mIU/mL (n=5) eventually showed occult infection, i.e, 10/30 occult hepatitis B-positive donors which could have been identified prior to transplantation. In the remaining 40 anti-HBc-positive donors, probability of occult infection was 62% for anti-HBe-positive and/or anti-HBs ≥ 58 mIU/mL; 29% for anti-HBe-negative and anti-HBs<58 mIU/mL.

CONCLUSIONS

In deceased donors, combining anti-HBc with other blood markers of hepatitis B exposure/infection allows to predict occult hepatitis B with certainty and speed in one third of cases. These findings might help refine the allocation of livers from anti-HBc-positive donors.

Prevalence of occult hepatitis B virus in plasma and peripheral blood mononuclear cell compartments of patients with chronic hepatitis C infection in tehran-iran

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is frequently reported in patients with chronic hepatitis C virus (HCV) infection. An association between OBI and more liver damage, cirrhosis, hepatocellular carcinoma, and reduced response to interferon therapy in patients with HCV infection is suggested.

OBJECTIVES

The aim of this study was to determine the prevalence of occult HBV, and evaluate its clinical influence on patients with chronic HCV.

PATIENTS AND METHODS

A cohort study including50 patients with positive results for HCV, and negative results for HBsAg tests was performed. The patients were divided into two groups: one group had positive results for both HCV and occult HBV tests (n = 18), and the other had positive results for HCV, but negative findings for occult HBV (n = 32). All were treated with PEG-IFN alpha-2a and Ribavirin. Presence of HCV RNA was followed in these patients.

RESULTS

HBV-DNA was detected using nested-PCR in 20% of plasma and 32.6% of peripheral blood mononuclear cell (PBMC) compartments. No significant differences were observed between patients with and without occult HBV for sex, age, duration of HCV infection, histological markers, presence of anti-HBc, HCV viral load, and HCV genotype. The response rate was significantly higher in patients with positive results for HBV-DNA test compared to those with negative findings (100% vs. 71.9 %, P < 0.05).

CONCLUSIONS

In conclusion, occult HBV was found in 36% of patients with negative results for HBsAg, but positive results for HCV. Detection of HBV-DNA in both PBMCs and plasma together in comparison with plasma alone provided more true identification of OBI.The SVR rate was significantly higher in coinfected patients than mono-infected ones.