Chance and necessity of simultaneous HBsAg and anti-HBs detection in the serum of chronic HBsAg carriers

Characteristics and clinical treatment outcomes of chronic hepatitis B children with coexistence of hepatitis B surface antigen (HBsAg) and antibodies to HBsAg

BACKGROUND

The coexistence of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb) represents an uncommon serological pattern observed in patients with hepatitis B virus (HBV) infection, and its underlying mechanism and clinical significance have not been well established. The aim of this study was to investigate the association between this serological profile and clinical treatment outcomes in children with chronic hepatitis B (CHB).

METHODS

This retrospective cohort study included 372 treatment-naïve CHB children from the Hunan Children's Hospital. The participants were categorized into HBsAb-positive group and HBsAb-negative group. The associations between HBsAb positive status to clinical outcomes were assessed using Cox proportional hazard regression. Receiver operating characteristic curve was conducted to evaluate the prediction ability in HBsAg loss.

RESULTS

The coexistence of HBsAg and HBsAb accounted for 23.39% (87/372) of the participants. The crude incidence rates of HBsAg loss, hepatitis B e antigen (HBeAg) clearance, and HBV-DNA undetectability were higher in the HBsAb-positive group compared with the HBsAb-negative group (37.46 vs. 17.37, 49.51 vs. 28.66, 92.11 vs. 66.54 per 100 person-years, respectively, all P < 0.05). The Cox regression analysis revealed a significant association between this serological profile and an increased likelihood of HBsAg loss (HR = 1.78, P = 0.001), and HBeAg clearance (HR = 1.78, P = 0.001). In addition, a combination of HBsAb ≥ 0.84 log10 IU/L and age ≤ 5 years can help identify patients likely to achieve HBsAg loss after antiviral therapy, with an AUC of 0.71.

CONCLUSIONS

Children who are positive for both HBsAg and HBsAb demonstrate a higher probability of favorable outcomes after antiviral treatment. Thus, children with HBsAb-positive CHB should be actively treated to achieve functional cure.

Unusual serological profile in hepatitis B virus (HBV) infection associated with a probable clinical case of acute exacerbation of pre-existing chronic HBV infection

BACKGROUND

Acute or chronic HBV infection in an individual can be laboratory characterized according to the serological profile of the viral markers in the bloodstream, and the dynamics monitoring of these markers is necessary to assess the disorder course and the infection outcome. However, under certain circumstances unusual or atypical serological profiles may be observed in both acute and chronic HBV infection. They are considered as such because they do not properly characterize the form or infection clinical phase or because they seem inconsistent, considering the viral markers dynamics in both clinical contexts. This manuscript comprises the analysis of an unusual serological profile in HBV infection.

METHODS AND RESULTS

This clinical-laboratory study, had as reference a patient who presented clinical profile suggestive of acute HBV infection after recent exposure, whose laboratory data were initially compatible with this clinical presentation. However, the serological profile analysis and its monitoring demonstrated unusual pattern of viral markers expression, which has been observed in several clinical contexts, and is often associated a number of agent- or host-related factors.

CONCLUSION

The serological profile analyzed here, associated with the biochemical markers serum levels found, is indicative of active chronic infection, consequence of viral reactivation. This finding suggests that in the event of unusual serological profiles in HBV infection, if the influence of agent- or host-related factors is not properly considered and neither the viral markers dynamics properly analyzed, there may be mistake in the infection clinical diagnosis, especially when the patient's clinical and epidemiological history is unknown.

A Novel Insertion in the Hepatitis B Virus Surface Protein Leading to Hyperglycosylation Causes Diagnostic and Immune Escape

Chronic hepatitis B virus (HBV) infection is a global health threat. Mutations in the surface antigen of HBV (HBsAg) may alter its antigenicity, infectivity, and transmissibility. A patient positive for HBV DNA and detectable but low-level HBsAg in parallel with anti-HBs suggested the presence of immune and/or diagnostic escape variants. To support this hypothesis, serum-derived HBs gene sequences were amplified and cloned for sequencing, which revealed infection with exclusively non-wildtype HBV subgenotype (sgt) D3. Three distinct mutations in the antigenic loop of HBsAg that caused additional N-glycosylation were found in the variant sequences, including a previously undescribed six-nucleotide insertion. Cellular and secreted HBsAg was analyzed for N-glycosylation in Western blot after expression in human hepatoma cells. Secreted HBsAg was also subjected to four widely used, state-of-the-art diagnostic assays, which all failed to detect the hyperglycosylated insertion variant. Additionally, the recognition of mutant HBsAg by vaccine- and natural infection-induced anti-HBs antibodies was severely impaired. Taken together, these data suggest that the novel six-nucleotide insertion as well as two other previously described mutations causing hyperglycosylation in combination with immune escape mutations have a critical impact on in vitro diagnostics and likely increase the risk of breakthrough infection by evasion of vaccine-induced immunity.

Characteristics of amino acid substitutions within the "a" determinant region of hepatitis B virus in chronically infected patients with coexisting HBsAg and anti-HBs

OBJECTIVES

Simultaneous positivity for both hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) is an atypical serological profile in chronic hepatitis B (CHB) patients. The exact mechanisms underlying the uncommon profile remains unclear. The aim of this study was to analyze the characteristics of amino acid substitutions within the "a" determinant region in a large cohort of CHB patients with coexistence of HBsAg and anti-HBs.

METHODS

In total 8687 CHB patients, of which 505 had coexisting HBsAg and anti-HBs, were enrolled in this study. Mutations within the "a" determinant region in 131 HBsAg+/anti-HBs+ patients and 150 age and gender matched HBsAg+/anti-HBs- patients were determined by direct sequencing and the characteristics of amino acid substitutions were analyzed.

RESULTS

The prevalence of coexistence of HBsAg and anti-HBs in the CHB patients was 5.81%. Compared to the control subjects, there were more amino acid substitutions in HBsAg+/anti-HBs+ patients (30.5% vs. 12.7%, P<0.001), especially within the first loop of the "a" determinant region. The most frequent amino acid substitution was located at position s126 and the predominant substitution was sI126T in HBsAg+/anti-HBs+ patients with genotype C. The frequency of additional N-glycosylation sites in HBsAg+/anti-HBs+ patients and the control subjects was 3.8% and 0.6%, respectively.

CONCLUSIONS

The accumulation and diversity of amino acid variations within "a" determinant region might contribute to the coexistence of HBsAg and anti-HBs. These findings extend understanding of the genetic mechanism of this atypical serological profile in CHB patients.

Understanding the patient population and test utilization for hepatitis B virus testing

BACKGROUND

Hepatitis B virus (HBV) infection remains a global concern with different epidemiologies due to several factors including migration, vaccination policies, and new antiviral treatment regimens. It is important to understand the characteristics of a patient population, including the prevalence of diseases, and to assess test utilization to understand and evaluate the clinical performance of laboratory tests and to improve the quality of clinical laboratories.

MATERIALS AND METHODS

In this study, we evaluated serologic and virologic laboratory tests including hepatitis B surface antigen, hepatitis B surface antibody, hepatitis B envelope antigen (HBeAg), hepatitis B envelope antibody, and HBV DNA in Korean adults who were exposed to HBV.

RESULTS

During the 1-year study period, we obtained 22 750 specimens from 17 523 adult Korean patients (>18.0 years; 9894 males and 7629 females) with a median age of 50.1 years (interquartile range, 42.2-58.2 years). Among them, five serologic and virologic laboratory tests were performed for 1340 (5.9%) specimens from 1172 adult Korean patients (>18.0 years; 647 males and 525 females) with a median age of 46.8 years (range, 19.0-84.5 years). The prevalence of serologic and virologic tests indicating several clinical situations was evaluated. The correlation coefficient between HBV DNA and HBeAg was ρ = 0.85 (P < .0001). However, 51.9% (695/1340) of samples did not show agreement between the two test results.

CONCLUSIONS

Analysis of the prevalence of patients categorized into five serologic and virologic laboratory results would be helpful to expand our knowledge about patient population characteristics and to improve test utilization.

Coexistence of low levels of HBsAg and high levels of anti-HBs may increase risk of hepatocellular carcinoma in chronic hepatitis B patients with high HBV load

OBJECTIVE

The clinical significance of coexistence of HBsAg/anti-HBs in chronic hepatitis B (CHB) patients remains controversial. This study was aimed to assess the association of this serological pattern with hepatocellular carcinoma (HCC) in patients with CHB.

METHODS

In this cross-section study, 206 CHB patients with coexistence of HBsAg/anti-HBs and 206 CHB patients with HBsAg alone were included to evaluate the risk of HCC development by logistic regression analysis. In addition, a retrospective cohort of 260 patients with CHB was recruited to estimate the cumulative incidence of HCC by Kaplan-Meier analysis.

RESULTS

The serological pattern of coexistence of HBsAg/anti-HBs, with high levels of ("High") HBsAg/low levels of ("Low") anti-HBs, were considered as independent risk factors for HCC. In particular, patients with "High" HBsAg/"High" anti-HBs [odds ratio (OR), 4.295; 95% confidence interval (CI), 1.104-16.699; p = 0.035] and "Low" HBsAg/ "High" anti-HBs (OR, 3.207; 95%CI, 1.299-7.919; p = 0.012) exhibited significantly higher risk for HCC development. However, only "Low" HBsAg /"High" anti-HBs might increase risk of HCC in CHB patients with high HBV load (logrank p < 0.001) in our cohort study.

CONCLUSION

The coexistence of "Low" HBsAg /"High" anti-HBs might increase the risk of HCC development in CHB patients with high HBV load, which reflected that the long-term interaction between immune response and virus might lead to the development of HCC. The identification of the patients with poor prognosis will help clinicians to refine the therapeutic decisions and individualize follow-up strategies.

Viral envelope-specific antibodies in chronic hepatitis B virus infection

While the cellular immune response associated with acute and chronic HBV infection has been thoroughly studied, the B cell response in chronic hepatitis B and the role of antibodies raised against the HBV envelope antigens in controlling and prevention of infection requires further investigation. The detection of anti-HBs antibodies is considered as one of the biomarkers for functional cure of chronic hepatitis B virus infection, as well as for protective immunity. Indeed, vaccine-induced neutralizing anti-HBs antibodies have been shown to protect against HBV challenge. Yet, the therapeutic potential of viral envelope-specific antibodies and the mechanism involved in protection and prevention of cell-to-cell transmission warrants additional investigative efforts. In this review, we will provide a critical overview of the available preclinical and clinical literature supporting the putative role of active and passive vaccination and neutralizing envelope-specific antibodies for therapeutic intervention in combination regimens intended to cure persistent HBV infection.

Mutation in the S gene a determinant of the hepatitis B virus associated with concomitant HBsAg and anti-HBs in a population in Northeastern Brazil

Mutations in the a determinant of S gene may develop co-existence of hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) in the serum of infected hepatitis B virus (HBV) individuals. Mutations in this region may change the antigenicity of HBsAg, which in turn, lead to escape of neutralizing action of anti-HBs antibodies. This study identified individuals with concomitant HBsAg and anti-HBs serological markers in individuals of Maranhão, Northeastern Brazil. Samples from a population-based study were evaluated for HBsAg, anti-HBs, and anti-HBc, and those that tested positive for simultaneous HBsAg and anti-HBs were submitted to HBV DNA quantification and S gene characterization by Sanger sequencing. Mutations were investigated in the a determinant located in major hydrophilic region (MHR) of the S gene. Among 3,984 samples analyzed, 92 (2.3%) were positive for HBsAg and three had the atypical HBsAg and anti-HBs-positive profile (3.26%). The frequency of HBsAg and anti-HBs co-existence was similar to previous studies. Only one individual harbored mutation in the S gene a determinant associated with this profile. Little is known about this phenomenon; however, studies as ours may contribute for future enlightenment of this important issue. J. Med. Virol. 89:458-462, 2017. © 2016 Wiley Periodicals, Inc.

Clinical and Virological Characteristics of Chronic Hepatitis B Patients with Coexistence of HBsAg and Anti-HBs

Coexistence of hepatitis B surface antigen (HBsAg) and antibody against HBsAg (anti-HBs) comprises an atypical serological profile in patients with chronic hepatitis B virus (HBV) infection. In this study, in total 94 patients with coexisting HBsAg and anti-HBs and 94 age- and sex-matched patients with positive HBsAg were characterized by quantitatively measuring HBsAg and HBV DNA, sequencing large S genes, and observing clinical features. Compared with common hepatitis B patients, the patients with coexisting HBsAg and anti-HBs had lower HBsAg and HBV DNA levels. These two groups had similar rate of pre-S deletion mutations. However, in patients with coexisting HBsAg and anti-HBs, more amino acid substitutions in the a determinant of S gene were observed in HBV genotype C, but not in genotype B. Fourteen patients with coexisting HBsAg and anti-HBs were followed up for an average of 15.5 months. There were no significant changes in the levels of HBsAg, anti-HBs, HBV DNA and ALT over the follow-up period. Compared with the baseline sequences, amino acid substitutions in the MHR of HBsAg occurred in 14.3% (2/14) patients. In conclusion, coexistence of HBsAg and anti-HBs may be associated with higher frequency of mutations in the a determinant of HBV genotype C.

Coexistence of circulating HBsAg and anti-HBs antibodies in chronic hepatitis B carriers is not a simple analytical artifact and does not influence HBsAg quantification

BACKGROUND

Presence at the same time of HBsAg and anti-HBs antibodies (HBsAg/Ab) is an entity sometimes encountered in chronic hepatitis B (CHB) carriers.

OBJECTIVES

This study was designed to characterize such serological profiles and to assess the reliability of serological marker quantification by three commercially available assays in this setting.

STUDY DESIGN

Among 2578 CHB identified patients, 129 (5%) had an HBsAg/Ab profile as determined by Abbott Architect. After exclusion of co-infections (HIV, HCV, HDV), HBV reactivation or HBIg treatment, 101 samples from 62 patients were tested for HBsAg and anti-HBs quantification using Architect, DiaSorin Liaison-XL and Roche Modular-Cobas. Influence of genotype and HBsAg variants was studied in 31 samples with HBV replication.

RESULTS

HBsAg detection was confirmed with the 3 techniques for 98% (n = 99) of the samples while the HBsAg/Ab profile was concordant between all techniques for 65% of them. The overall correlation between the 3 HBsAg quantification techniques was good (R(2): 0.94-0.97). The median HBsAg concentration was comparable for the 99 samples whatever the used technique but a bias of -0.11 and 0.02 log IU/mL were noticed for DiaSorin and Roche compared to Abbott, respectively. Anti-HBs quantifications were poorly correlated between techniques with major discrepancies observed. Genotype and substitutions within the "a" determinant showed an impact on HBsAg quantification.

CONCLUSIONS

The double HBsAg/Ab profile is not an analytical artifact and is confirmed on all commercially available techniques. While such profile does not influence HBsAg quantification, differences of HBsAg quantification were noticed according to HBV genotype or HBsAg variant.