Hepatitis B virus markers in anti-HBc only positive individuals

Hepatitis B vaccines

Immunization is the most effective way to prevent transmission of HBV and, hence, the development of acute or chronic hepatitis B. The national strategy to eliminate transmission of the virus in the United States includes vaccination of all newborn infants, children, adolescents, and high-risk adults. Postexposure prophylaxis is also advocated, depending on the vaccination and anti-HBs status of the exposed person. Seroprotection after vaccination, defined as anti-HBs > or = 10 mIU/mL, is achieved in over 95% of all vaccinees. The hepatitis B vaccines are very well tolerated with usually minimal adverse effects. Predictors of non-response include increasing age, male gender, obesity, tobacco smoking, and immunocompromising chronic disease. For those who remain nonresponders after the second series of vaccination, adjuvants such as GM-CSF may be considered, but their results are variable.

Review article: hepatitis vaccination in patients with chronic liver disease

Evidence regarding the outcomes of viral super-infection in patients with chronic liver disease and practical strategies for hepatitis A and B vaccination of these individuals are reviewed. Patients with acute hepatitis A and chronic hepatitis B have a more severe clinical course and a higher death rate compared with otherwise healthy individuals with hepatitis A, and these differences are most pronounced in older patients and those with histological evidence of chronic hepatitis or cirrhosis, rather than in asymptomatic hepatitis B carriers. Patients with acute hepatitis A super-infection and chronic hepatitis C have an increased risk of fulminant hepatitis and death. In addition, patients with other chronic liver diseases also appear to be at increased risk for more severe disease with superimposed hepatitis A. Patients with chronic hepatitis B and hepatitis C virus co-infection have more severe laboratory abnormalities, more severe histological disease, a greater frequency of cirrhosis and complications of cirrhosis, and a higher incidence of hepatocellular carcinoma. Vaccines for both hepatitis A and B are safe and effective if used early in the course of chronic liver disease. Hepatitis A and B vaccination should be part of the routine management of patients with chronic liver disease, preferably as early as possible in the natural course of their disease.

No evidence of hepatitis B virus activity in patients with anti-HBc antibody positivity with or without anti-hepatitis C virus antibody positivity

BACKGROUND

The serological pattern of anti-HBc antibody positivity without both, HBsAg and anti-HBs antibody positivity may be present in up to 4% of the population of Europe and the United States.

OBJECTIVES

The aim of the present study was to determine the hepatitis B virus (HBV) activity by detection of serum HBV DNA in patients with anti-HBc antibody positivity only and with confirmed anti-hepatitis C virus (anti-HCV) antibody positivity or without anti-HCV antibody positivity.

STUDY DESIGN

A total of 141 patients positive for anti-HBc antibodies only, were investigated on serum HBV DNA load. Patients were classified into two groups: patients with confirmed positive anti-HCV antibodies (group 1) and patients without anti-HCV antibodies (group 2).

RESULTS

Demographic data of patient groups were similar. In 66 of 70 patients with anti-HBc antibodies and anti-HCV antibodies (group 1), serum HCV RNA was detected; the remaining 4 patients were HCV RNA negative but the presence of anti-HCV antibodies was confirmed by the line probe assay. In none of the patients, with anti-HBc antibodies and without anti-HCV antibodies (group 2), serum HCV RNA was detected. In none of the patients, serum HBV DNA was detected.

CONCLUSION

In this study, serum HBV DNA could not be detected in patients with anti-HBc antibodies only. There seems to be no need for determination of serum HBV DNA in patients without clinical evidence of chronic liver disease. Nevertheless, it would be useful to test patients with progressive liver disease and those, which belong to high-risk groups such as hemophiliacs, intravenous drug abusers, patients on hemodialysis, and immunocompromised patients.

Prevalence of hepatitis B virus DNA in anti-HBc-positive/HBsAg-negative sera correlates with HCV but not HIV serostatus

BACKGROUND

Hepatitis B virus (HBV) DNA often remains detectable in serum despite clinical recovery and loss of HBsAg.

OBJECTIVE

To study whether coinfection with HIV and HCV influence the chance of detecting HBV DNA in sera with markers of past hepatitis B.

STUDY DESIGN AND RESULTS

The test panel included 160 anti-HBc-positive/HBsAg-negative sera collected in the diagnostic setting. The following parameters were determined in the sera: anti-HIV (32% positive), anti-HCV (34% positive), HCV RNA (18% positive), and anti-HBs (37% positive). A highly sensitive PCR (90%-detection limit 100 copies/ml) amplifying the terminal protein (TP) region of HBV was established and HBV DNA was detected in 12.5% of the samples. In 70% of these samples, the HBV DNA concentration was below 500 copies/ml as measured by real-time PCR in the S gene. Logistic regression analysis revealed that the chance of detecting HBV DNA was increased by a positive HCV serostatus (odds ratio 5.0, 95%-CI 1.6-15.7), whereas HIV coinfection (odds ratio 2.0, 95%-CI 0.7-5.8), anti-HBs (odds ratio 0.9, 95%-CI 0.3-2.6), and HCV RNA status (odds ratio 0.4, 95%-CI 0.1-1.7) had no statistically significant influence. In contrast, the chance of detecting HCV RNA in the subgroup of anti-HCV-positive sera was increased by HIV coinfection (odds ratio 4.5, 95%-CI 1.2-17.4). Sequencing of the TP PCR products revealed neither a specific phylogenetic origin of the circulating HBV DNA nor clustering of uncommon mutations in the TP region.

CONCLUSIONS

The prevalence of HBV DNA in serum of anti-HBc-positive/HBsAg-negative subjects correlates with HCV rather than HIV serostatus.

Electrochemical behavior and detection of hepatitis B virus DNA PCR production at gold electrode

Sequence-known short-stranded hepatitis B virus (HBV) DNA fragment (181 bps) was obtained by PCR method. The strategy for its electrochemical detection was designed by covalently immobilizing single-stranded HBV DNA on gold electrode surface via carboxylate ester as a linkage between 3'-hydroxy end of DNA and carboxyl group of thioglycolic acid (TGA) self-assembled monolayer. The hybridization reaction on surface was evidenced by electrochemical methods using ferrocenium hexafluorophosphate (FcPF6) as an electroactive indicator. The interactions of Fc+ with single-stranded (ss) and double-stranded (ds) HBV DNA immobilized on TGA monolayer were studied. The difference between the responses of Fc+ at ss- and ds-DNA/Au electrodes suggested that this hybridization biosensor could be conveniently used to monitor DNA hybridization with a high sensitivity. AC impedance and XPS techniques have been employed to characterize the immobilization of ss-DNA on the gold surface.

Detection of immune-complex-dissociated nonstructural-1 antigen in patients with acute dengue virus infections

Accurate and timely diagnosis of dengue virus (DEN) infections is essential for the differential diagnosis of patients with febrile illness and hemorrhagic fever. In the present study, the diagnostic value of a newly developed immune-complex dissociated nonstructural-1 (NS-1) antigen dot blot immunoassay (DBI) was compared to a commercially available DEN antigen detection kit (denKEY Blue kit; Globio Co., Beverly, Mass.) and a reverse transcription-PCR (RT-PCR) kit. Serial serum or plasma samples (n = 181) obtained from 55 acute DEN-infected patients were used. In samples obtained from 32 of these 55 DEN-infected patients, viral RNA could be detected by RT-PCR. DEN antigen was detected in only 10 of these 55 patient samples by using the denKEY kit. When these samples were treated with acid to release the immune-complex-associated NS-1 antigen for detection by DBI, 43 of these 55 patients were found to be positive for DEN NS-1 antigen. In nondissociated samples, 22 of these patients were found to be positive by the DBI. In the presence of DEN-specific immunoglobulin M antibodies, both viral RNA and DEN (NS-1) antigen could be detected. The number of positive samples identified by RT-PCR and DBI from these patients with primary DEN infections varied between 28 and 78%. In secondary DEN infections, the number of samples that tested positive by the DBI after immune-complex dissociation (DIS-DBI) was 25% higher than the number of samples that tested positive by RT-PCR and was 35% higher than that determined by nondissociated antigen (NDIS-DBI) detection. We conclude that the denKEY kit has limited diagnostic value for acute DEN infections compared to the RT-PCR and the NDIS-DBI and DIS-DBI methods. We clearly demonstrate that in secondary DEN infections the dissociation of NS-1 immune complexes is essential for early diagnosis of DEN infections.

The significance of 'anti-HBc only' in the clinical virology laboratory

BACKGROUND

Isolated detection of hepatitis B core antibody (anti-HBc) in the absence of surface antigen (HBsAg) or antibody (anti-HBs) has been reported, particularly among individuals infected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). The significance of this phenomenon is unknown and it is unclear whether all individuals with such serological pattern need further molecular investigations.

OBJECTIVES

To determine the prevalence of 'anti-HBc only' in samples referred to a clinical virology laboratory and to evaluate its significance and possible mechanisms.

STUDY DESIGN

Samples identified as anti-HBc positive (389/4359, 8.9%) during an 11-month period were investigated for HBsAg, anti-HBs, anti-HCV and anti-HIV. 'Anti-HBc only' samples were tested for HBV DNA using a nested qualitative PCR. Viral loads were measured in samples with detectable HBV DNA and the DNA sequences were analysed.

RESULTS

Of 379 samples with detectable anti-HBc, 155 (40.9%) were 'anti-HBc only'. HBV DNA was detected in 6/151 (4%), all of which had a viral load <400 copies per ml. Anti-HIV was found in 50/151 (33.1%) and anti-HCV in 14/151 (9.3%). Of these, only one of the HIV infected patients had detectable HBV DNA. Phylogenetic analysis of the HBV surface gene from three patients showed a variety of genotypes (A, E and G). One sequence had a mutation in codon 144, which has previously been reported to give false negative HBsAg results.

CONCLUSIONS

'Anti-HBc only' is a common phenomenon in the clinical virology laboratory but only a small proportion of samples had detectable HBV DNA. The presence of HBsAg mutants with possible false negative HBsAg test result is of concern. Samples with 'anti-HBc only' could be used to monitor the emergence of these mutants.

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Frequent occult hepatitis B virus infection in patients infected with human immunodeficiency virus type 1

The presence of hepatitis B virus (HBV) serological markers was investigated in 170 patients (137 male, 33 female) infected with human immunodeficiency virus (HIV) type 1. Antibodies to the hepatitis B core antigen (anti-HBc antibodies) were detected in 115 (68%) patients. Of these 115, 14 (12%) were hepatitis B surface antigen (HBsAg) positive, 60 (52%) presented anti-HBs antibodies, and 41 (35%) were anti-HBc positive only. All 115 of the anti-HBc positive samples were tested for HBV DNA by using two polymerase chain reaction (PCR) assays that amplify the core and pre-S regions of the HBV genome, respectively. HBV DNA was detected in 23 samples: 7 of 14 (50%) HBsAg-positive samples, 12 of 60 (20%) anti-HBs-positive samples, and 4 of 41 (10%) samples positive for anti-HBc only. Six samples (all HBsAg positive) were positive in both PCR assays and 17 samples were HBV DNA positive in only one assay. The mean viral load in HBsAg-positive patients was higher than that observed in HBsAg-negative patients. A number of patients were receiving treatment with lamivudine, a drug that interferes with both HBV and HIV replication. However, neither the rate of HBV DNA positivity nor HBV load was significantly different between patients treated with lamivudine and those not treated with this drug.

Evaluation of two new automated assays for hepatitis B virus surface antigen (HBsAg) detection: IMMULITE HBsAg and IMMULITE 2000 HBsAg

In recent years the diagnostic industry has developed new automated immunoassays for the qualitative detection of hepatitis B virus (HBV) surface antigen (HBsAg) in serum and plasma samples that are performed on analyzers that permit a high-speed throughput, random access, and primary tube sampling. The aim of the present study was the evaluation of two new automated HBsAg screening assays, IMMULITE HBsAg and IMMULITE 2000 HBsAg, from Diagnostic Products Corporation. The new HBsAg assays were compared to well-established tests (Auszyme Monoclonal [overnight incubation, version B], IMx HBsAg, AxSYM HBsAg, and Prism HBsAg [all from Abbott] and Elecsys HBsAg [Roche Diagnostics]). In the evaluation were included seroconversion panels, sera from the acute and chronic phases of infection, dilution series of various HBsAg standards, HBV subtypes and S gene mutants. To challenge the specificity of the new assays, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. IMMULITE HBsAg and IMMULITE 2000 HBsAg, although not as sensitive as the Elecsys HBsAg assay, were equivalent to the AxSYM HBsAg assay and showed a higher sensitivity than the Auszyme Monoclonal B and IMx HBsAg systems for detection of acute infection in seroconversion panels. The specificities (100%) of both IMMULITE assays on unselected blood donors and potentially interfering samples were comparable to those of the alternative assays after repeated testing. In conclusion, the new IMMULITE HBsAg and IMMULITE 2000 HBsAg assays show a good sensitivity for HBsAg detection compared to other well-established tests. The specificity on repeatedly tested samples was equivalent to that of the alternative assays. The rapid turnaround time, primary tube sampling, and on-board dilution make it an interesting assay system for clinical laboratory diagnosis.

Hepatitis B virus activity in patients with anti-hepatitis C virus antibody positivity and hepatitis B antigen positivity

BACKGROUND

Co-infection with hepatitis B virus (HBV) and HCV seems to be relatively frequent. There might be a mutual influence on replication activity of HBV and HCV.

OBJECTIVES

To determine the HBV activity in patients with serum HCV RNA and HBsAg positivity and in those with confirmed anti-HCV antibody and HBsAg positivity but serum HCV RNA negativity.

STUDY DESIGN

A total of 1,200 anti-HCV antibody positive samples were investigated. Samples of HCV RNA and HBsAg positive patients were compared with those of confirmed anti-HCV and HBsAg positive but serum HCV RNA negative patients. HBV activity was tested with the quantitative Cobas Amplicor HBV Monitor Test (Roche Diagnostic Systems, Pleasanton, CA).

RESULTS

Of all studied patients with chronic hepatitis C (serum HCV RNA positivity) only 1.0% were found to be HBsAg positive. In contrast, of all patients with confirmed anti-HCV positivity but serum HCV RNA negativity, 11.9% tested HBsAg positive. The median of HBV DNA levels of patients with serum HCV RNA positivity and HBeAg seroconversion (4.0 x 10(2) HBV DNA copies per ml) was found to be slightly lower than that of patients with serum HCV RNA negativity and HBeAg seroconversion (2.5 x 10(3) HBV DNA copies per ml; P>0.05). The median of HBV DNA levels of patients with serum HCV RNA positivity but without HBeAg seroconversion (1.1 x 10(4) HBV DNA copies per ml) was found to be significantly lower than that of patients with serum HCV RNA negativity but without HBeAg seroconversion (2.6 x 10(7) HBV DNA copies per ml; P<0.05).

CONCLUSION

A mutual effect on HBV and HCV replication could be observed. The molecular assay for quantification of serum HBV DNA was found to be useful for the routine diagnostic laboratory.

Frequency and load of hepatitis B virus DNA in first-time blood donors with antibodies to hepatitis B core antigen

The objective of this study was to determine the frequency and load of hepatitis B virus (HBV) DNA in anti-HBc-positive first-time blood donors; it was designed to contribute to determining whether anti-HBc screening of blood donations might reduce the residual risk of posttransfusion HBV infection. A total of 14 251 first-time blood donors were tested for anti-HBc using a microparticle enzyme immunoassay; positive results were confirmed by a second enzyme-linked immunosorbent assay (ELISA). For the detection of HBV DNA from plasma samples, we developed a novel and highly sensitive real-time polymerase chain reaction (PCR) assay. The 95% detection limit of the method amounted to 27.8 IU/mL, consistent with the World Health Organization (WHO) international standard for HBV DNA. A total of 216 blood donors (1.52%) tested anti-HBc-positive in both tests, and 205 of them (16 HBsAg(+), 189 HBsAg(-)) were tested for HBV DNA. In 14 (87.5%) of the HBsAg-positive blood donors, HBV DNA was repeatedly detected, and in 3 (1.59%) of the HBsAg-negative donors, HBV DNA was also found repeatedly. In the 3 HBV DNA-positive, HBsAg-negative cases, anti-HBe and anti-HBs (> 100 IU/L) were also detectable. HBV DNA in HBsAg-negative as well as HBsAg-positive samples was seen at a low level. Thus, HBV DNA is sometimes found in HBsAg-negative, anti-HBc-positive, and anti-HBs-positive donors. Retrospective studies on regular blood donors and recipients are necessary to determine the infection rate due to those donations. Routine anti-HBc screening of blood donations could probably prevent some transfusion-transmitted HBV infections.