Clinical and virological features of occult hepatitis B in patients with HBsAg seroclearance post-treatment or spontaneously

Estimates of the prevalence of occult HBV infection in Asia: a systematic review and meta-analysis

PURPOSE

Occult Hepatitis B virus infection (OBI) is of great significance to the transmission of Hepatitis B virus (HBV) and the evolution of the patient's clinical outcome. We conducted a systematic review and meta-analysis to estimate the prevalence of OBI in Asia.

METHODS

Literature search was conducted in PubMed, Cochrane Library database, Web of Science and Embase with the keywords of 'Hepatitis B virus', 'occult infection', 'prevalence'. 70 studies were included in the meta-analysis. Meta-analysis was performed using random-effects models to calculate the pooled prevalence of OBI and 95% confidence interval (CI). The data were analyzed in R 4.1.2.

RESULTS

The overall prevalence of OBI was 4% (95%CI: 0.03-0.06) in Asia. Subgroup analysis based on geographic region showed a prevalence of 3% (95%CI 0.02-0.06) in East Asia, 9% (95%CI 0.05-0.15) in West Asia, 3% (95%CI 0.01-0.11) in Southern Asia and 9% (95%CI 0.05-0.15) in Southeast Asia. Subgroup analysis demonstrated a prevalence of 1% (95%CI 0.00-0.02) in general population, 5% (95%CI: 0.03-0.08) in high-risk population, 9% (95%CI: 0.03-0.22) in the human immunodeficiency virus (HIV)-infected patient, 18% (95%CI: 0.09-0.32) in the hepatopathy patients.

CONCLUSION

Based on the meta-analysis of the prevalence of OBI in different populations, we concluded that the prevalence of OBI in the high-risk population, hepatopathy patients, and HIV-infected patients was higher than that in the general population. A systematic review showed that OBI was associated with disease progression and prognosis. Therefore, these populations should be routinely screened for OBI and promptly intervened to avoid promoting disease progression.

Animal Models of Hepatitis B Virus Infection-Success, Challenges, and Future Directions

Chronic hepatitis B virus (HBV) infection affects more than 250 million people worldwide, which greatly increases the risk for terminal liver diseases, such as liver cirrhosis and hepatocellular carcinoma (HCC). Even though current approved antiviral therapies, including pegylated type I interferon (IFN) and nucleos(t)ide analogs, can effectively suppress viremia, HBV infection is rarely cured. Since HBV exhibits a narrow species tropism and robustly infects only humans and higher primates, progress in HBV research and preclinical testing of antiviral drugs has been hampered by the scarcity of suitable animal models. Fortunately, a series of surrogate animal models have been developed for the study of HBV. An increased understanding of the barriers towards interspecies transmission has aided in the development of human chimeric mice and has greatly paved the way for HBV research in vivo, and for evaluating potential therapies of chronic hepatitis B. In this review, we summarize the currently available animal models for research of HBV and HBV-related hepadnaviruses, and we discuss challenges and future directions for improvement.

Cytokine profile during occult hepatitis B virus infection in chronic hepatitis C patients

Background

The hepatitis B virus (HBV) is one of the leading causes of acute, chronic and occult hepatitis (OBI) representing a serious public health threat. Cytokines are known to be important chemical mediators that regulate the differentiation, proliferation and function of immune cells. Accumulating evidence indicate that the inadequate immune responses are responsible for HBV persistency. The aim of this study were to investigate the cytokines IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10 and IL-17A in patients with OBI and verify if there is an association between the levels of these cytokines with the determination of clinical courses during HBV occult infection.

Methods

114 patients with chronic hepatitis C were investigated through serological and molecular tests, the OBI coinfected patients were subjected to the test for cytokines using the commercial human CBA kit. As controls, ten healthy donors with no history of liver disease and 10 chronic HBV monoinfected patients of similar age to OBI patients were selected.

Results

Among 114 HCV patients investigated, 11 individuals had occult hepatitis B. The levels of cytokines were heterogeneous between the groups, most of the cytokines showed higher levels of production detection among OBI/HCV individuals when compared to control group and HBV monoinfected pacients. We found a high level of IL-17A in the HBV monoinfected group, high levels of TNF-α, IL-10, IL-6, IL-4 and IL-2 in OBI/HCV patients.

Conclusion

These cytokines could be involved in the persistence of HBV DNA in hepatocytes triggers a constant immune response, inducing continuous liver inflammation, which can accelerate liver damage and favor the development of liver cirrhosis in other chronic liver diseases.

Incidence and determinants of spontaneous hepatitis B surface antigen seroclearance and seroconversion in hepatitis B e antigen-negative chronic infection patients: A population-based prospective cohort

Seroclearance of hepatitis B surface antigen (HBsAg) has been widely studied; however, seroconversion of HBsAg and characteristics of viral load among hepatitis B e antigen (HBeAg)-negative chronic infection patients after HBsAg lost is not clear. We performed a large-scale study in a HBeAg-negative chronic infection cohort to evaluate spontaneous HBsAg seroclearance incidence from October 2012 to April 2017 in Jiangsu province, China. We also elucidated the characteristics of HBsAg seroconversion and hepatitis B virus (HBV) DNA detectability among patients who cleared HBsAg. A total of 2997 HBeAg-negative chronic infection patients (mean age 52.3 ± 12.9 years at baseline) were included. With 10 519 person-years of follow-up, 348 patients successfully spontaneously cleared HBsAg, with an incidence rate of 3.31 per 100 person-years. Patients with HBV DNA detectable ~1999 IU/mL at baseline had a lower probability of HBsAg seroclearance relative to those with undetectable HBV DNA, with a hazard ratio of 0.31 (95% CI = 0.23, 0.41). HBsAg seroconversion occurred in 37.3% of those patients who cleared HBsAg. The geometric mean of anti-HBs among those with HBsAg conversion was 79.4 mIU/mL. Female had a higher HBsAg seroconversion rate (P = 0.011). Among those with HBsAg seroclearance, 11.2% still had HBV DNA levels of higher than 100 IU/mL. Patients with higher HBV DNA at baseline had a higher risk of detectable HBV DNA levels even after HBsAg seroclearance (P < 0.001). This study reveals HBsAg seroconversion rates and HBV DNA undetectability epidemiological characteristics of patients with HBsAg seroclearance and suggests that monitoring HBV DNA is needed when managing HBeAg-negative chronic patients, even after clearing HBsAg.

Detection and molecular characterisation of a diagnosis escape variant associated with occult hepatitis B virus in Brazil

BACKGROUND

Many studies have identified mutations in the hepatitis B surface antigen (HBsAg) as important factors limiting the ability of commercial serological assays to detect this viral antigen. However, an association between mutations in the HBsAg gene and the occurrence of occult HBV infection (OBI) in patients has not been established.

OBJECTIVES

To detect hepatitis B virus (HBV) DNA in patients with anti-HBc as a unique serological marker, a previously published, cost-effective TaqMan-based real-time polymerase chain reaction (PCR) test with minor groove binding probes was adapted for use in this study. The current study also aimed to investigate HBsAg mutations and genotypes of HBV in OBI at the Viral Hepatitis Ambulatory Clinic in Rio de Janeiro to determine any possible association.

METHODS

Intra-assay and inter-assay reproducibility were determined, and the mean coefficient of variation values obtained were 2.07 and 3.5, respectively. Probit analysis indicated that the 95% detection level was 25 IU/mL. The prevalence of OBI was investigated in 35 serum samples with an ‘anti-HBc alone’ profile from individuals who attended our clinic between 2011 and 2013.

FINDINGS

HBV DNA was detected in only one sample, resulting in an OBI rate of 2.9%. Nucleotide sequencing of the pre-S/S region was performed to genotype and analyse mutations within the HBsAg gene of this HBV DNA. The HBV in the OBI case was classified as sub-genotype A1, and a sequence analysis of the small S gene revealed 12 mutations in the major hydrophilic region compared to the consensus A1 sequence. Most of these mutations occurred in amino acid residues that have been reported as clinically relevant because they have been implicated in vaccine escape and/or inability to detect HBsAg by commercial serological assays.

MAIN CONCLUSIONS

Our study suggests the importance of specific HBsAg mutations, different from those in D, B, and C genotypes, in sub-genotype A1 HBV associated with OBI.

Animal models of HBV infection

The mechanisms determining hepatitis B virus (HBV) persistence and pathogenesis are not fully elucidated, but appear to be multi-factorial. Current medication to repress viral replication is available; however, the unique replication strategies employed by HBV enable the virus to persist within the infected hepatocytes. Consequently, cure is rarely achieved. Progresses in HBV research and preclinical testing of antiviral agents have been limited by the narrow species- and tissue-tropism of the virus, the paucity of infection models available and the restrictions imposed by the use of chimpanzees, the only animals fully susceptible to HBV infection. Mice are not HBV permissive but major efforts have focused on the development of mouse models of HBV replication and infection, such as the generation of humanized mice. By presenting the different animal models available, this review will highlight the most important and clinically relevant findings that have been retrieved from the respective systems.

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.

Hepatitis B virus infection among institutionalized mentally ill patients in Brazil

Objectives

The main objective was to evaluate HBV infection and occult HBV infection (OBI) cases in mentally ill patients based on serological and molecular profiles.

Material and methods

Serum samples of 333 long-stay mentally ill patients were tested for the prevalence of HBV markers by serological (ELISA) and molecular (PCR) assays. The PCR products were sequenced to determine viral genotypes.

Results

It was observed a global prevalence of 12.9% (43/333) for HBV infection markers, considering HBsAg and/or anti-HBc positivity. Fourteen samples tested positive for anti-HBs alone. All samples positive (n = 57) for any HBV serological markers were tested for HBV-DNA and six were positive: HBsAg/anti-HBc (n = 1), anti-HBc/anti-HBs (n = 1), anti-HBs alone (n = 1), and anti-HBc alone (n = 3). The rate of OBI was 9.2% (5/54) from samples that were anti-HBc and/or anti-HBs positive. All sequenced samples were characterized as genotype A.

Conclusion

The high rate of HBV infections found in this study suggests the possibility of HBV transmission due to risk factors displayed by some patients, and highlights the importance of vaccination of susceptible patients and the staff of that institution.

Occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host’s strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI.

Updates on the treatment and outcomes of dual chronic hepatitis C and B virus infection

Dual hepatitis C virus (HCV)/hepatitis B virus (HBV) infection is found in HBV or HCV endemic areas, and in specific populations exhibiting a high risk of parenteral viral transmission. Clinical observations have revealed that HCV/HBV dually infected patients demonstrate a higher risk of liver disease progression compared with HBV or HCV monoinfected patients. The viral activity responsible for liver disease progression can be determined by examining the viral loads of HCV and HBV and by conducting liver biopsy examinations. Recent trials have confirmed that the combination therapy of peginterferon alpha-2a or 2b and ribavirin for dual hepatitis patients with HCV dominance appears to be as effective and safe as it is in patients with HCV monoinfections. Strikingly, approximately 60% of dually infected patients with inactive hepatitis B before treatment develop HBV reactivation after the clearance of the HCV. The clinical significance of this HBV reactivation and the strategy to prevent and treat this event should be determined. Furthermore, approximately 30% of dually infected patients lost hepatitis B surface antigen (HBsAg) within 5 years after the start of peginterferon-based therapy, and 40% of them harbored occult HBV infection. The underlying mechanisms of their accelerating HBsAg seroclearance and the development of occult HBV await further investigations. Moreover, the optimal treatment strategies for dually infected patients who are seropositive for the hepatitis B e antigen must be explored. Finally, the advent of new direct-acting antiviral-based anti-HCV therapy may change the optimal therapies for patients with dual hepatitis in the near future, which warrants further clinical trials.