Immune complexes in sera of children with HBV-mediated glomerulonephritis

Multiple serum samples from 27 children with hepatitis B virus (HBV)--mediated glomerulonephritis (GN) were screened for the presence of immune complexes by an antigen-specific method. For this purpose an immunoenzymatic test was set up, applying a solid-phase Clq and the enzyme-conjugated antibodies: anti-HBs and anti-HBe. Complexes of HBsAg were found in sera of 15 children (55.6%), while complexes of HBeAg--in sera of 12 children (44.4%). Molecular weight of complexes was measured in sera of three patients, disclosing the values of 2.5-3.3 X 10(6) daltons for HBsAg complexes and 2.5-3.2 X 10(5) daltons for HBeAg complexes. Immune deposits consisting of hepatitis B virus antigen (HBeAg), IgG and C3 were detected in the glomeruli by immunoperoxidase and immunofluorescent assays respectively, in 3 out of 4 patients with membranous glomerulonephritis (MGN). No genetic defect of the complement system was found by the measurement of total haemolytic activity of complement and concentration of early complement components. From the analysis of clinical and laboratory data it was concluded that the appearance of HBeAg complexes correlated with more severe course of the disease.     

Hepatitis B virus (HBV) antigen-pulsed monocyte-derived dendritic cells from HBV-associated hepatocellular carcinoma patients significantly enhance specific T cell responses in vitro

To investigate whether hepatitis B virus (HBV) antigen-pulsed monocyte-derived dendritic cells (MoDC) could mount a T cell response in hepatocellular carcinoma (HCC) patients associated with chronic HBV infection, peripheral blood mononuclear cells (PBMCs) from 36 HBV-associated HCC patients were induced into MoDC and pulsed with hepatitis B core antigen (HBcAg) and hepatitis B surface antigen (HBsAg), alone and in combination. Co-stimulatory molecules CD80, CD86 and CD40, as well as human leucocyte antigens D-related (HLA-DR) were found to express at the highest level on MoDC pulsed with HBcAg or HBsAg + HBcAg, at a median level on MoDC pulsed with HBcAg or HBsAg alone, and at the lowest level on non-antigen-pulsed MoDC. Interleukin (IL)-10 and IL-12 cytokines were released by antigen-pulsed MoDC at increased levels in the order: no-antigen < HBsAg < HBcAg < HBcAg + HBsAg. MoDC pulsed with HBcAg or HBsAg + HBcAg also had the strongest ability to stimulate autologous T cell proliferation and intracellular interferon (IFN)-gamma production. HBcAg- or HBsAg + HBcAg-pulsed MoDC could also induce HBV core peptide-specific CD8(+) T cell proliferation determined by tetramer staining. In addition, the antigen-pulsed MoDC were found to have a stronger capacity to produce IL-12 and induce T cell response in vitro for patients with higher alanine transaminase (ALT) levels than those with lower ALT levels, indicating that antigen pulse could substantially reverse the impaired function of MoDC in primary HCC patients with active chronic hepatitis B. In conclusion, HBV antigen-pulsed MoDC from HCC patients with chronic hepatitis B could induce HBV-specific T cell response in vitro.     

Correlation of HBV DNA and monoclonal reactivity to HBsAg in serum of patients with HBV infection

Hepatitis B virus (HBV) DNA hybridization assay, a monoclonal radioimmunoassay (M-RIA) for hepatitis B surface antigen (HBsAg) and conventional polyclonal immunoassays for HBV associated antigens were used to study sera from patients on dialysis and with acute hepatitis B. HBV DNA was detectable in hepatitis B e antigen (HBeAg) negative patients with acute hepatitis but not in HBsAg+ HBeAg- dialysis patients. In acute hepatitis, HBsAg immunoreactivity by M-RIA could still be detected even though a commercial immunoassay for HBsAg, the AUSRIA II, and the HBV DNA assay were no longer positive. Unlike in acute HBV infection, serum HBV DNA was detectable in dialysis patients who were AUSTRIA II negative but M-RIA positive. Serial determination of HBsAg by M-RIA and HBV DNA revealed episodes of HBV DNA positivity months after both the HBsAg was no longer positive by polyclonal immunoassay. Thus, the M-RIA for HBsAg and the molecular hybridization technique for HBV DNA are sensitive and specific assays for the identification of potentially infectious individuals who would not have been characterized as such based on the results of conventional polyclonal immunoassays.     

Molecular and serological aspects of HBsAg-negative hepatitis B virus infections in North America

A few hepatitis B virus (HBV) infections are characterized by the presence of HBV DNA in serum or liver tissue, or both, in the absence of detectable hepatitis B surface antigen (HBsAg) in serum. However, such infections have rarely been described previously in North American patients. In the present study, 31 hepatocellular carcinoma (HCC) patients from the United States and Canada who had no detectable HBsAg in their serum were studied. In these 31 HBsAg-negative HCC patients, HBV DNA was detected in HCC and/or in adjacent nontumorous liver tissue using nested polymerase chain reaction (PCR) in 5/9 (56%) patients from the United States and in 12/22 (55%) from Canada. The 17 HBV DNA-positive/HBsAg-negative patients from the United States and Canada included 9 without any serological markers for HBV and 8 with detectable antibodies to hepatitis B core antigen. In these patients, HBV genotype C was the most prevalent genotype (11/17; 64%). HBV genotypes have not been previously reported in HCC patients from North America. Replicative intermediate forms of HBV (covalently closed circular HBV DNA) were detected in 2/17 (12%) HBV DNA-positive/HBsAg-negative patients, indicating that at least two of these patients had actively replicating HBV infections. The use of tests to detect HBV DNA permitted the identification of HBV infections in HBsAg-negative HCC patients from North America. Among these patients, those with antibody to hepatitis C virus (HCV) would otherwise have been designated "HCV-associated HCCs" based on serological tests alone. These findings provide a new perspective on determining the possible viral etiologies of HCCs in North America.     

Hepatitis B virus antigens in liver resections from patients with hepatocellular carcinoma

A high rate of hepatitis B virus (HBV) antigen carriers among patients with hepatocellular carcinoma (HCC) has been recorded from areas of endemic HBV infections in Africa and Asia, but there are only rare and contradictory data for Europe. 12 specimens of resected liver tissue were immunohistologically investigated for hepatitis B surface antigen (HBsAg) as well as for hepatitis B core antigen (HBcAg). HBsAg was contained in non-tumorous liver tissue in 66 per cent of these cases. In two cases detection of HBcAg in the liver provided evidence to replication of the virus. HBcAg plus HBsAg were present in tumour tissue in one case. All of the HBV antigen carriers did not have chronic hepatitis. On the other hand, all patients with chronic hepatitis had HBV antigens in their liver tissue. HBV antigens were detectable in 7 non-cirrhotic livers, but were contained in only one of two cirrhotic livers. These results are likely to suggest a possible relevance of HBV infection to the aetiology of HCC even in central Europe without customary liver cirrhosis.     

Three heads are better than two: Hepatitis B core-related antigen as a new predictor of hepatitis B virus-related hepatocellular carcinoma

Patients with chronic hepatitis B virus (HBV) infection are at risk of developing hepatocellular carcinoma (HCC), and serum markers reflecting viral replication are potential predictors for HCC development. Besides the levels of serum HBV DNA and hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg) quantification is an emerging serological marker for viral replication. Unlike HBV DNA and HBsAg, HBcrAg is a covalently closed circular DNA-derived protein marker, consisting of hepatitis B e antigen (HBeAg), p22cr, and hepatitis B core antigen. In treatment-naïve HBV patients, higher HBcrAg levels are shown to be associated with an increased risk of HCC in several studies. More importantly, HBcrAg may complement HBV DNA level to predict HCC development. For example, an Asian treatment-naïve cohort study’s data showed that HBcrAg level of 4 log U/mL was effective to stratify HCC risk in HBeAg-negative patients with intermediate viral loads, who may not need antiviral therapy because of the low to moderate risk of HCC. In patients receiving prolonged nucleos(t)ide analogue with profound viral suppression, most data indicated that HBV DNA and HBsAg levels no longer serve as HCC predictors. However, several studies suggested on-treatment HBcrAg levels may remain as an HCC predictor. In summary, HBcrAg level can be a useful biomarker for treatment-naïve patients, but its value in on-treatment patients needs validation. The next challenge is how to combine HBcrAg with the other viral markers to construct a better HCC prediction model, optimizing the management of HBV patients.     

Persistence of intrahepatic hepatitis B virus DNA integration in patients developing hepatocellular carcinoma after hepatitis B surface antigen seroclearance

Background/AimsThe role of hepatitis B virus (HBV) integration into the host genome in hepatocarcinogenesis following hepatitis B surface antigen (HBsAg) seroclearance remains unknown. Our study aimed to investigate and characterize HBV integration events in chronic hepatitis B (CHB) patients who developed hepatocellular carcinoma (HCC) after HBsAg seroclearance.MethodsUsing probe-based HBV capturing followed by next-generation sequencing technology, HBV integration was examined in 10 samples (seven tumors and three non-tumor tissues) from seven chronic carriers who developed HCC after HBsAg loss. Genomic locations and patterns of HBV integration were investigated.ResultsHBV integration was observed in six patients (85.7%) and eight (80.0%) of 10 tested samples. HBV integration breakpoints were detected in all of the non-tumor (3/3, 100%) and five of the seven (71.4%) tumor samples, with an average number of breakpoints of 4.00 and 2.43, respectively. Despite the lower total number of tumoral integration breakpoints, HBV integration sites in the tumors were more enriched within the genic area. In contrast, non-tumor tissues more often showed intergenic integration. Regarding functions of the affected genes, tumoral genes with HBV integration were mostly associated with carcinogenesis. At enrollment, patients who did not remain under regular HCC surveillance after HBsAg seroclearance had a large HCC, while those on regular surveillance had a small HCC.ConclusionsThe biological functions of HBV integration are almost comparable between HBsAg-positive and HBsAg-serocleared HCCs, with continuing pro-oncogenic effects of HBV integration. Thus, ongoing HCC surveillance and clinical management should continue even after HBsAg seroclearance in patients with CHB.     

Hepatitis B virus concentrations in serum determined by sensitive quantitative assays in patients with established chronic hepatitis delta virus infection.

To clarify the correlation between hepatitis B virus (HBV) DNA levels and serum alanine aminotransferase (ALT) levels in patients with established chronic hepatitis delta virus (HDV) infection, sensitive HBV quantitative assays were used for the study. Thirty-four consecutive patients with chronic liver disease who were positive for both hepatitis B surface antigen (HBsAg) and antibody to HDV (anti-HDV), including 19 patients with chronic hepatitis, 8 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma. All were negative for hepatitis Be antigen (HBeAg) and positive for antibody to HBeAg. HBV DNA was detected in 25 (73.5%) of the 34 patients using real-time detection PCR, and the HBV DNA levels of these patients were significantly lower compared with HBeAg status and ALT level-matched patients with chronic liver disease positive for HBsAg but negative for anti-HDV. There was no correlation between serum HBV DNA and ALT levels among the 34 patients with chronic liver disease positive for anti-HDV. Whereas serum ALT levels in anti-HDV-positive HBsAg carriers with HDV RNA were significantly higher than those without HDV RNA. Liver damage in patients with established chronic HDV infection may be caused mainly by ongoing HDV infection not by HBV replication.     

Cell-mediated immunity to hepatitis B surface antigen in man.

An aqueous preparation of hepatitis B virus (HBV) vaccine was used as an intradermal skin test antigen to assess delayed hypersensitivity to hepatitis B surface antigen (HBsAg). Thirty-five persons were tested including 10 individuals seronegative for all HBV markers, 10 positive for HBsAg (chronic carriers) and 15 positive for antibody to HBsAg (anti-HBs), five of whom had received the HBV vaccine. All patients were also studied for lymphocyte blastogenic responses to phytohaemagglutinin, concanavalin A, pokeweed mitogen and purified HBsAg. Only one individual had a positive delayed skin test reaction to HBsAg. This person had received the HBV vaccine and had high titres of anti-HBs in serum. However, neither this individual nor any other subject exhibited a positive lymphocyte blastogenic response to HBsAg in vitro. Thus, delayed hypersensitivity skin test reactivity to HBsAg was not detected after natural infection with HBV and was rarely present in hyperimmunized individuals. In vitro assays of immune responsiveness failed to demonstrate cellular immunity to HBsAg even in hyperimmunized persons. These studies provide no evidence that cell-mediated immunity to HBsAg plays a role in the immunopathogenesis of acute or chronic type B hepatitis.     

Membranous glomerulopathy associated with hepatitis B core antigen immune complexes in children.

Direct immunofluorescence, immunoelectron microscopy, and special immunohistochemical procedures including guinea pig complement fixation, differential elution, and in situ antigen binding were employed in an immunomorphologic analysis of kidney biopsy specimens from 98 children with clinically diagnosed nephrotic syndrome and/or glomerulonephritis (GN). Glomerular deposits of hepatitis B virus (HBV) antigens, immunoglobulins, and complement were detected in specimens from 24 children, all seropositive for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (HBcAg). Of these, 21 cases were diagnosed as membranous glomerulopathy (MGN), 1 as membranoproliferative GN, and 2 as diffuse mesangial proliferative GN. HBaAg was identified as the only HBV antigen in about a third of the cases of MGN, whereas in another third it was accompanied by HBsAg. HBsAg was the only HBV antigenic component detected in the glomerular deposits in the remaining third of the cases of this GN form. The results of this study indicate that apart from, or in addition to, HBsAg immune complexes, HBcAg immune complexes may also participate in the pathogenesis of a significant number of MGN cases in children subclinically infected with HBV. A possibility that these complexes include nonparticulate, presumably low-molecular-weight HBaAg components and that they are found in an environment of antibody-excess is discussed.     

Detection of hepatitis B virus DNA in the serum of Canadian hepatitis B surface antigen negative,anti-HBc positive individuals,using the polymerase chain reaction

Continuing hepatitis B virus (HBV) infection is normally associated with the presence of hepatitis B surface antigen (HBsAg) in the serum. In spite of sensitive screening assays for HBsAg, rare cases of post-transfusion HBV infection are still observed. Antibody to hepatitis B core antigen (anti-HBc) often indicates remote HBV infection but DNA hybridisation and more sensitive polymerase chain reaction (PCR) assays have demonstrated that some HBsAg negative individuals, positive for anti-HBc, have continuing HBV replication. To determine the incidence of ongoing HBV infection in a Canadian HBsAg negative, anti-HBc positive population we studied three groups with this combination of HBV markers: Group A, 36 patients referred for investigation of raised serum aminotransferases; Group B, 21 Canadian Red Cross blood donors; Group C, seven vaccinees in an Ottawa Health Care Student hepatitis B vaccination programme. The PCR was carried out using a nested PCR reaction with primers specific for the pre-core region of HBV. Seven of 36 (19%) patients in Group A had detectable HBV DNA whereas none of Group B or C were positive. This data indicates that in some HBsAg negative patients with ongoing hepatic inflammation, continuing HBV replication may persist. This was not observed in any healthy blood donors or health care students investigated. Larger studies are required, but this data would suggest that, in Canada, the addition of anti-HBc testing for all blood donors for detection of low level HBV replication would not be indicated. © 1994 Wiley-Liss, Inc.     

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. Electronic Publication     

HBV-DNA hybridization in hepatocellular carcinoma associated with alcohol in Japan

To clarify the role of the hepatitis B virus (HBV) in hepatocellular carcinoma (HCC) associated with alcohol consumption, HBV-DNA in the liver of 19 patients with HCC were investigated. HBV-DNA was examined by Southern blot hybridization. HBV-DNA was integrated into tumor cells from five out of six (83%) patients with HCC associated with HBs antigen (HBsAg)-positive post-hepatitic liver cirrhosis (LC), but this was not related to the history of alcohol intake. In 13 HCC patients of HBsAg-negative alcoholic LC, HBV-DNA integration was not detected in any patient. These findings suggest that HBV does not play a major role in the pathogenesis of HCC in HBsAg-negative alcoholics in Japan.     

Validity of the rapid strip assay test for detecting HBsAg in patients admitted to hospital in Uganda

Commercially available rapid strip assays (RSAs) for hepatitis B surface antigen (HBsAg) are used for most routine clinical testing in sub‐Saharan Africa. This study evaluated the validity of RSA and a more sophisticated enzyme immunoassay (EIA) with confirmation by nucleic acid testing (NAT) in hospitalized patients in Uganda. Sera from 380 consecutive patients collected and tested for HBsAg and anti‐HIV in Kampala, Uganda by RSA were sent frozen to Dallas for EIA including HBsAg, total anti‐hepatitis B core, hepatitis B e antigen, and anti‐HIV. NAT was performed on all HBsAg‐positives and on a random sample of 102 patients that were HBsAg‐negative by both assays. Overall, 31 (8%) were HBsAg positive by RSA while 50 (13%) were HBsAg‐positive by EIA; 26 were concordant between the two assays. Of 55 HBsAg‐positive patients, nearly all showed detectable serum hepatitis B virus (HBV) DNA by bDNA (46) or PCR (4) assay. The 26 patients who were HBsAg positive by both EIA and RSA had significantly higher median serum HBV DNA levels than the 24 patients who were HBsAg positive by EIA alone. An additional 12/102 (12%) HBsAg negative patients had very low serum HBV DNA levels by NAT. Several differences in expected results of serologic testing were observed in this large series of African patients. RSA HBsAg testing is less sensitive than EIA; even EIA failed to detect all HBV DNA positive sera. A more complex testing protocol than RSA alone will be needed in Africa to improve patient care. J. Med. Virol. 82:1334–1340, 2010. © 2010 Wiley‐Liss, Inc.     

New assays for quantitative determination of viral markers in management of chronic hepatitis B virus infection.

We performed a quantitative study of serum hepatitis B virus (HBV) markers, including new parameters such as pre-S1 antigen (Ag), pre-S2 Ag, and anti-HBx, in 88 chronic hepatitis B surface antigen (HBsAg) carriers. New IMx assays for HBsAg and immunoglobulin M (IgM) anti-HBc detection were also used. The population studied was composed of 65 chronic hepatitis cases (40 positive for hepatitis B antigen [HBeAg] and 25 positive for anti-HBe) and 23 anti-HBe-positive, asymptomatic HBsAg carriers. Serum HBsAg levels detected by IMx were higher in HBeAg-positive than in anti-HBe-positive HBsAg carriers (all patient subgroups included) and correlated with the serum HBV DNA level (P = 0.0001). Both pre-S1 and pre-S2 Ags were detected by enzyme immunoassays in almost all HBsAg carriers. Both pre-S1 and pre-S2 Ag titers correlated positively with the serum HBsAg concentration (P = 0.0001), but only the pre-S1 Ag titer correlated with the level of serum HBV DNA (P = 0.02). The detection of low levels of IgM anti-hepatitis B core (anti-HBc) antibodies by IMx was associated with the presence of liver disease (P = 0.05) but not with the level of viral replication. The prevalence of anti-HBx antibodies detected by the enzyme immunoassay was slightly, although not significantly, higher in patients with high levels of HBV DNA (greater than 100 pg/ml) than in patients without detectable HBV DNA (P = 0.16). In anti-HBe-positive chronic HBsAg carriers, the quantitative detection of serum HBV DNA, pre-S Ag titers, and IgM anti HBc allowed us to predict which patients suffered from chronic liver disease and/or supported viral replication (P < 0.05). In a follow-up study of eight patients undergoing antiviral therapy, the clearance of both pre-S1 Ag and HBV DNA was associated with a subsequent clearance of HBV. Therefore, the quantitative determination of HBV DNA, pre-S Ags, IgM anti-HBc may prove useful for the decision to use and the monitoring of antiviral therapy, especially in anti-HBe-positive HBsAg carriers.     

乙型肝炎肝硬化肾脏损害的免疫病理与临床关系探讨

对乙型肝炎肝硬化尸检１２例肾脏病理与免疫病理进行观察，免疫病理发现在肾小球的内膜和系膜区有乙型肝炎病毒抗体ＩｇＭ、ＩｇＡ、ＩｇＧ和免疫复合物Ｃ３、Ｃｌｑ沉积，只发现１例有ＨＢｓＡｂ阳性。提示可能肾脏损害与ＨＢＶ直接作用的关系不大，而作为抗原引起体液免疫或通过循环免疫复合物沉积与肾病变关系较密切。     

Clinical significance of a highly sensitive enzyme immunoassay of hepatitis B surface antigen using a novel electron spin resonance technique.

We developed a highly sensitive enzyme immunoassay (EIA), the p-AP/HHTIO method, that detects serum hepatitis B surface antigen (HBsAg) by measuring stabilized nitroxide radicals using a novel electron spin resonance technique [Matsuo et al. (1998) Free Radic Biol Med 25:929-935]. To demonstrate the clinical significance of this method and to reveal occult hepatitis B virus (HBV) infection in patients, we used the method to analyze serum samples of 30 patients with acute or fulminant hepatitis who were negative for HBsAg by standard EIA, and those of seven chronic HBV carriers who became negative for HBsAg during a follow-up period by standard EIA. We also examined serum HBV DNA by amplification of the HBV S gene, using the polymerase chain reaction (PCR) technique. The p-AP/HHTIO method showed that 9 of 20 (45%) patients with acute hepatitis and 2 of 10 (20%) with fulminant hepatitis were positive for HBsAg; PCR detected HBV DNA in these HBsAg-positive patients. Antibody against hepatitis B core antigen was detected in one patient with fulminant hepatitis. The p-AP/HHTIO method demonstrated prolonged seropositivity of HBsAg even after standard EIA showed a loss of HBsAg in all seven HBV carriers. Our p-AP/HHTIO method is useful for screening and diagnosing HBV infection in patients with liver diseases who are negative for conventional HBV-related serological markers.     

Chronic liver disease: the detection and characterization of circulating immune complexes.

Circulating immune complexes containing IgG, IgM and hepatitis B surface antigen (HBsAg) in sera from groups of patients with various liver diseases were detected by both the C1q and conglutinin solid phase assays. Elevated levels of antigen non-specific immune complexes were observed in sera from all groups and complexes containing IgG were present to a greater extent than were IgM-containing complexes. Higher levels of complexes were generally obtained using the conglutinin assay than the C1q assay and the two assays were shown to preferentially bind complexes of different size ranges and antigen-antibody ratios. Only sera from HBsAg-positive patients had complexes containing HBsAg, and although serum HBsAg titres and levels of HBsAg-containing complexes were correlated, the correlation coefficient was low. The mean levels of immune complexes and the frequency of positive sera varied between different disease categories, but there was little correlation between levels of the three types of complexes detected by the two tests. Assay of immune complexes in sequential serum samples from an individual patient revealed considerable variation in the levels of the three complex types, demonstrating that the measurement of complexes in single serum samples is of limited value in assessing the potential significance of circulating immune complexes in hepatitis B.     

Improved Detection of Hepatitis B Virus Surface Antigen by a New Rapid Automated Assay

The performance of hepatitis B virus (HBV) surface antigen (HBsAg) screening assays is continuously improved in order to reduce the residual risk of transfusion-associated hepatitis B. In a multicenter study, a new automated rapid screening assay, Elecsys HBsAg (Roche Diagnostics), was compared to well-established tests (Auszyme Monoclonal [overnight incubation] version B and IMx HBsAg [Abbott]). Included in the evaluation were 23 seroconversion panels; sera from the acute and chronic phases of infection; dilution series of various HBsAg standards, HBV subtypes, and S gene mutants; and isolated anti-HBV core antigen-positive samples. To challenge the specificity of the new assay, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. Elecsys HBsAg showed a higher sensitivity for HBsAg subtypes ad, ay, adw2, adw4, ayw1, ayw2, ayw4, and adr detection in dilution series of different standards or sera than Auszyme Monoclonal version B and/or IMx HBsAg. Acute hepatitis B was detected in 11 to 16 of 23 seroconversion panels between 2 and 16 days earlier with Elecsys HBsAg than with the alternative assays. Elecsys HBsAg and Auszyme Monoclonal version B detected HBsAg surface mutants with equal sensitivity. The sensitivity and specificity of Elecsys HBsAg were 100%. Auszyme Monoclonal version B had a 99.9% specificity, and its sensitivity was 96.6%. IMx HBsAg showed a poorer sensitivity and specificity than the other assays. In conclusion, Elecsys HBsAg permits earlier detection of acute hepatitis B and different HBV subtypes than the alternative assays. By using highly sensitive HBsAg screening assays, low-level HBsAg carriers among isolated anti-HBV core antigen-positive individuals can be detected.