Reactivation of hepatitis B virus infection with persistently negative HBsAg on three HBsAg assays in a lymphoma patient undergoing chemotherapy

Prevalence and molecular characteristics of occult hepatitis B virus infection among blood donors in Huzhou City, eastern China

Occult hepatitis B virus (HBV) infection (OBI) is a significant challenge for HBV prevention and control. We investigated the prevalence and surface (S) gene mutations of OBI among blood donors in Huzhou City, eastern China. The hepatitis B surface antigen (HBsAg) was routinely screened among 44,256 blood donors. HBV-DNA was detected using the Roche cobas®system. Serum samples that were HBsAg negative and HBV-DNA positive were selected, and the HBV S gene was amplified and sequenced. HBV genotype and S gene mutations were analyzed. The OBI rate in these blood donors was 0.070 % (31/44,256). Among the blood donors with OBI, only two cases (2/31, 6.5 %) were anti-HBc negative. The S gene sequences of 28 samples were successfully obtained, and we found that HBV genotype C (21/28, 70 %) was predominant among blood donors with OBI. Most S gene mutations were associated with OBI, and the high frequency mutations included N40S, G44E, Q51R/P, T113A/S,T118K/M, P120Q/S/T, and Y161F/S. Notably, amino acid substitutions at some sites differed from those reported previously, such as Y72F, G102V, P127L, Q129P, and S143T. Additionally, six novel mutations (S31I/N/R, P46L, S58C, C76Y, Y200F/C, and I208T) that may be associated with OBI were found. OBI was detected in a certain proportion of blood donors in Huzhou City. S gene mutations play an important role in OBI development. Further research is required to explore the functions of novel S gene mutants in OBI pathogenesis. The findings of this study may provide important insights to prevent HBV transmission through blood transfusions.

Biomarkers of transfusion transmitted occult hepatitis B virus infection: Where are we and what next?

Blood transfusion is a vital procedure, where transfusion-transmitted infection of hepatitis B virus (HBV) remains an important issue, especially from blood donors with occult hepatitis B virus infection (OBI). Occult hepatitis B virus infection is a complex entity to detect using surrogate blood biomarkers for intrahepatic viral transcriptional activity, requiring a continually refined battery of tests utilised for screening. This review aims to critically evaluate the latest advances in the current blood biomarkers to guide the identification of OBI donors and discuss novel HBV markers that could be introduced in future diagnostic practice. Challenges in detecting low HBV surface antigen levels, mutants, and complexes necessitate ultrasensitive multivalent dissociation assays, whilst HBV DNA testing requires improved sensitivity but worsens inaccessibility. Anti-core antibody assays defer almost all potentially infectious donations but have low specificity, and titres of anti-surface antibodies that prevent infectivity are poorly defined with suboptimal sensitivity. The challenges associated with these traditional blood HBV markers create an urgent need for alternative biomarkers that would help us better understand the OBI. Emerging viral biomarkers, such as pre-genomic RNA and HBV core-related antigen, immunological HBV biomarkers of T-cell reactivity and cytokine levels, and host biomarkers of microRNA and human leucocyte antigen molecules, present potential advances to gauge intrahepatic activity more accurately. Further studies on these markers may uncover an optimal diagnostic algorithm for OBI using quantification of various novel and traditional blood HBV markers. Addressing critical knowledge gaps identified in this review would decrease the residual risk of transfusion-transmitted HBV infection without compromising the sustainability of blood supplies.

The sK122R mutation of hepatitis B virus (HBV) is associated with occult HBV infection: Analysis of a large cohort of Chinese patients

BACKGROUND

Occult HBV infection (OBI) is of great concern due to their complicated diagnosis and potential for public transmission.

OBJECTIVE

The study aimed to determine the clinical prevalence of OBI and if viral immune escape-associated mutations contribute to the occurrence of OBI.

STUDY DESIGN

A total of 91,037 HBV-infected patients with different related illnesses who were admitted to the Fifth Medical Center of Chinese PLA General Hospital from January 2005 to December 2017 were tested for OBI. Serum samples from 62 patients with OBI manifestations (OBI patients) and 124 matched non-OBI patients were sequenced for possible immune escape-associated mutations within the major hydrophilic region of HBV S protein. HBsAg and HBV DNA levels in representative viral strains were measured.

RESULTS

Of the 91,037 tested patients, 487 (0.53 %) were negative for HBsAg but positive for HBV DNA and were defined as OBI patients. The prevalence in different illness categories varied. Immune escape-associated mutations were more frequently detected in OBI patients than in non-OBI patients (59.68 % vs. 35.48 %, P < 0.01), as did the coexistence of multiple mutations (43.55 % vs. 22.58 %, P < 0.01). Specifically, the prevalence rates of sT118 K, sK122R, and sV168A were increased in OBI patients. Strains with sK122R mutants (sK122R, sK122R + D144E, sK122R + C121R + D144E, and sK122R + F134L + D144E) from a follow-up OBI patient all showed significantly lower levels of HBsAg production than a wild-type strain.

CONCLUSIONS

The study clarified the clinical prevalence of OBI, verified the influence of immune escape-associated mutations, and identified the role of the sK122R mutation in multiple OBI patients.

Detection of circulating hepatitis B virus immune escape and polymerase mutants among HBV-positive patients attending Institut Pasteur de Bangui, Central African Republic

Background

Previous studies in the Central African Republic (CAR) have reported the presence of hepatitis B virus (HBV) recombinant genotype E/D and a suspicion of immune escape mutants (IEMs), without further investigation into their impact on prevention and diagnosis. Consequently, this study investigated HBV mutations among hepatitis B surface antigen (HBsAg)-positive patients attending Institut Pasteur de Bangui in the CAR.

Methods

Sera from a total of 118 HBsAg-positive patients with no previous history of HBV treatment or vaccination at the Institut Pasteur de Bangui, were sampled between 2017 and 2019. Subsequently, the region spanning the surface and polymerase genes of HBV was amplified by PCR and sequenced. HBV sequences were genotyped/subgenotyped by phylogenetic analysis and serotyped based on predicted amino acid residues at positions s122, s127, s140, s159, and s160. They were then analyzed for HBV IEMs and polymerase mutations.

Results

The region spanning the surface and polymerase genes was successfully amplified and sequenced for 51 samples. Of the HBV sequences, 49 were genotype E and two were genotype A subgenotype A1; these were serotyped as ayw4 and ayw1, respectively. Potential IEMs sY100C, sA128V, and sM133T, and several polymerase mutants were identified.

Conclusions

This study raises awareness of the need for further studies to be conducted on a large scale to better understand HBV mutations for improved disease control and prevention strategies in the country.

Roles of Hepatitis B Virus Mutations in the Viral Reactivation after Immunosuppression Therapies

Reactivation of hepatitis B virus (HBV) is a major problem in patients receiving chemotherapy for malignant diseases or immunosuppression therapies. It has been thought that a reduction in the immune responses might result in the reactivation of HBV replication from covalently closed circular DNA (cccDNA) residing in hepatocytes. However, not only the host’s immune status, but also viral mutations have been reported to be associated with reactivation. Especially, several case reports about amino acid mutations in hepatitis B surface antigen (HBsAg) that escape from immune reactions have been reported, and recent reports showed that the frequencies of such mutations are higher than previously expected. In this review, we summarize the characteristics of viral mutations, including immune escape mutations in HBV-reactivated patients, and discuss their significance.

Characterization of Novel Hepatitis B Virus PreS/S-Gene Mutations in a Patient with Occult Hepatitis B Virus Infection

Objective

The impact of hepatitis B virus (HBV) preS/S-gene mutations on occult HBV infection (OBI) is not fully understood. This study characterized multiple novel HBV preS/S-gene mutants obtained from an OBI patient.

Methods

PreS/S-gene mutants were analyzed by clonal sequencing. Viral replication and expression were analyzed by transfecting HBV genomic recombinants into HepG2 cells.

Results

Twenty-one preS/S-gene mutants were cloned from four sequential serum samples, including 13 mutants that were not previously documented: (1) sI/T126V+sG145R; (2) preS1 nt 3014−3198 deletion; (3) preS1 nt 3046−3177 deletion; (4) preS1 nt 3046−3177 deletion+s115−116 “INGTST” insertion; (5) preS1 nt 3046−3177 deletion+s115−116 “INGTST” insertion+sG145R; (6) preS1 nt 3115−3123 deletion+sQ129N; (7) preS1 nt 3115−3123 deletion+s126−127 “RPCMNCTI” insertion; (8) s115−116 “INGTST” insertion; (9) s115−116 “INGTST” insertion+sG145R; (10) s126−127 “RPCMNCTI” insertion; (11) preS1 nt 2848−2862 deletion+preS2 initiation codon M→I; (12) s122−123 “KSTGLCK” insertion+sQ129N; and (13) preS2 initiation codon M→I+s131−133TSM→NST. The proportion of preS1 nt 3046−3177 deletion and preS2 initiation codon M→I+s131−133TSM→NST mutants increased in the viral pool with prolonged disease. The 13 novel OBI-related mutants showed a 51.2−99.9% decrease in HBsAg levels compared with that of the wild type. Additional N-glycosylation-associated mutations, sQ129N and s131−133TSM→NST, but not s126−127 “RPCMNCTI,” greatly attenuated anti-HBs binding to HBsAg. Compared with the wild type, replication and surface antigen promoter II activity of the preS1 nt 3046−3177 deletion mutant decreased by 43.3% and 97.0%, respectively.

Conclusion

PreS/S-gene mutations may play coordinated roles in the presentation of OBI and might be associated with disease progression. This has implications for HBV diagnosis and vaccine improvement.

Mutations associated with occult hepatitis B in HIV-positive South Africans

Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations-those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references-were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro.

Reactivation of hepatitis B virus in patients with undetectable HBsAg undergoing chemotherapy for malignant lymphoma or multiple myeloma

Despite increasing reports of hepatitis B virus (HBV) reactivation in hematological malignancies, its incidence, and risk factors are still obscure. The aim of this study was to clarify the frequency and risk factors of HBV reactivation in hepatitis B surface antigen (HBsAg) undetectable patients with malignant lymphoma or multiple myeloma, during or after chemotherapy. A total of 109 patients with undetectable HBsAg undergoing chemotherapy for malignant lymphoma or multiple myeloma were enrolled in this study. Anti-hepatitis B surface (anti-HBs) and anti-hepatitis B core (anti-HBc) were checked before treatment, and HBV DNA in sera was quantified monthly during and after chemotherapy. Out of 109 patients, 42 (38.5%) had anti-HBs and 59 (54.1%) had anti-HBc. Among the 59 anti-HBc positive patients, four patients (4/59, 6.8%) showed HBV reactivation during 20.5 median follow-up months. In all four patients with HBV reactivation, peripheral lymphocyte counts before chemotherapy were lower than those without HBV reactivation (P=0.033). HBV reactivation occurred during and after chemotherapy containing rituximab for non-Hodgkin lymphoma. Four patients, who had HBV reactivation, did not develop de novo hepatitis due to HBV reactivation and were able to undergo chemotherapy against malignant lymphoma as scheduled. Monitoring of HBV DNA in sera is useful for the early diagnosis of HBV reactivation, and preemptive therapy is an useful alternative to prevent hepatitis due to HBV reactivation. Patients must be monitored periodically for HBV-DNA levels during and after chemotherapy.

Impaired virion secretion by hepatitis B virus immune escape mutants and its rescue by wild-type envelope proteins or a second-site mutation

Hepatitis B virus immune escape mutants have been associated with vaccine failure and reinfection of grafted liver despite immune prophylaxis, but their biological properties remain largely unknown. Transfection of 20 such mutants in a human hepatoma cell line identified many with severe impairment in virion secretion, which can be rescued to various extents by coexpression of wild-type envelope proteins or introduction of a novel glycosylation site. Consistent with their role in maintaining intra- or intermolecular disulfide bonds, cysteine residues within the "a" determinant are critical for virion secretion.

Hepatitis B virus management to prevent reactivation after chemotherapy: a review

PURPOSE

Reactivation of hepatitis B virus (HBV) infection after chemotherapy can lead to liver failure and death. Conflicting recommendations regarding HBV screening in cancer patients awaiting chemotherapy mean that some patients at risk for HBV reactivation are not being identified and treated with prophylactic antiviral therapy.

METHODS

We performed a narrative review of the existing evidence regarding screening for and management of HBV infection among patients with cancer using Ovid Medline, PubMed, and the Cochrane Library.

RESULTS

Our review showed inconsistencies in the definition and management strategies for HBV reactivation. The timeframe of reactivation is variable, and its molecular mechanisms are not clear. There are five effective antiviral agents that can be used as prophylaxis to prevent reactivation of HBV infection in cancer patients; however, the optimal drug and duration of therapy are unknown. Reactivation is more commonly reported in patients with hematologic malignancies receiving rituximab treatment, but reactivation can occur after other chemotherapies and in patients with solid tumors. Screening with all three screening tests-HBsAg, anti-HBc, and anti-HBs-allows the most thorough interpretation of a patient's serologic profile and assessment of reactivation risk; however, decision-making and cost-effectiveness studies are needed to determine optimal screening strategies.

CONCLUSIONS

Prevention of reactivation of HBV infection depends on identification of patients at risk and initiation of antiviral prophylaxis, but data to guide screening and treatment strategies are lacking. Additional research is necessary to accurately define and predict reactivation, identify best antiviral treatment strategies, and identify cost-effective HBV screening strategies.

Occult Hepatitis B (OBH) in Clinical Settings

CONTEXT

Occult hepatitis B (OHB), or persistent HBV DNA in patients who are hepatitis B surface antigen (HBsAg) negative, is a recently recognized entity. In an attempt to summarize the issues, this review presents an overview of the current proposed hypothesis on the clinical relevance and also updates the knowledge on the classification of OHB in different clinical settings.

EVIDENCE ACQUISITION

OHB COULD BE FOUND IN DIFFERENT POPULATION AND CLINICAL BACKGROUNDS INCLUDING: viral co-infections (with either human immunodeficiency or hepatitis C viruses), HBV chronic carriers, dialysis patients, transplantation settings and certain clinical situations (named in here: special clinical settings) with no apparent distinguishable clinical parameters.

RESULTS

The exact magnitude, pathogenesis, and clinical relevance of OHB are unclear. Even the possible role exerted by this cryptic infection on liver disease outcome, and hepatocellular carcinoma development remains unknown.

CONCLUSIONS

Monitoring of Individuals with positive anti-HBc, mass immunization programs and improvement in diagnostic tools seem to be important to control the probability of transmission of HBV through cryptic HBV infection.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Antiviral treatment in patients with hepatitis B virus infection receiving chemotherapy

Reactivation of hepatitis B virus (HBV) is a frequent complication of chemotherapy in patients with HBV infection. Reactivation is characterized by increased levels of serum HBV DNA, abnormal liver function and hepatic failure. HBV reactivation inevitably leads to disruption of chemotherapy and severe clinical results in some cases. Nucleoside analogues play an important role in preventing and reducing the risk for HBV reactivation and HBV-associated morbidity and mortality. This paper gives a systematic review of the definition, mechanism and causes of HBV reactivation and summarizes the principles and problems for antiviral treatment in patients with HBV reactivation. It is strongly recommended that all patients should be screened for HBV serum markers before chemotherapy and preventive therapy with nucleoside analogues be given in patients with HBV. The use of potent antiviral drugs with low resistance potential and close viral monitoring during therapy are important for patients with HBV infection undergoing chemotherapy.