Akinori Rokuhara

Sensitive Enzyme Immunoassay for Hepatitis B Virus Core-Related Antigens and Their Correlation to Virus Load

ABSTRACT A sensitive enzyme immunoassay (EIA) specific for hepatitis B virus core antigen (HBcAg) and hepatitis B e antigen (HBeAg) was developed. We designated the precore/core gene products as hepatitis B virus (HBV) core-related antigens (HBcrAg). In order to detect HBcrAg even in anti-HBc/e antibody-positive specimens, the specimens were pretreated in detergents. The antibodies are inactivated by this pretreatment and, simultaneously, the antigens are released and the epitopes are exposed. The assay demonstrated 71 to 112% recovery using HBcrAg-positive sera. We observed no interference from the tested anticoagulants or blood components. When the cutoff value was tentatively set at 103 U/ml, all healthy control (HBsAg/HBV-DNA negative; n = 108) and anti-HCV antibody-positive (n = 59) sera were identified as negative. The assay showed a detection limit of 4 × 102 U/ml using recombinant antigen. Detection limits were compared in four serially diluted HBV high-titer sera. The HBcrAg assay demonstrated higher sensitivity than HBV-DNA transcription-mediated amplification (TMA) or HBeAg radio immunoassay (RIA) in the dilution test. HBcrAg concentrations correlated well with HBV-DNA TMA (r = 0.91, n = 29) and in-house real-time detection-PCR (r = 0.93, n = 47) in hepatitis B patients. On HBeAg/anti-HBe antibody seroconversion panels, the HBcrAg concentration changed in accordance with HBV-DNA levels. HBcrAg concentration provides a reflection of HBV virus load equivalent to HBV-DNA level, and the assay therefore offers a simple method for monitoring hepatitis B patients.

Clinical evaluation of a new enzyme immunoassay for hepatitis B virus core‐related antigen; a marker distinct from viral DNA for monitoring lamivudine treatment

Summary. We aimed to assess the clinical performance of a newly developed chemiluminescence enzyme immunoassay (CLEIA) for the detection of hepatitis B virus (HBV) core‐related antigen (HBcrAg) in patients with chronic HBV infection. A total of 82 patients with chronic HBV infection and 167 HBV‐negative controls were studied. HBcrAg was measured by CLEIA with monoclonal antibodies to hepatitis B e antigen (HBeAg) and hepatitis B core antigen (HBcAg), and HBV DNA was measured by transcription‐mediated amplification assay (TMA) and in‐house real‐time detection polymerase chain reaction (RTD‐PCR). The HBcrAg assay detected viremia in 189 of 216 samples (88%) collected from 72 patients whilst the TMA assay detected viremia in 178 of the 216 samples (82%) (P = 0.019). The HBcrAg concentration correlated linearly with the HBV DNA concentration (P < 0.001) over a range which varied 100 000‐fold. The accuracy in the measurement of the patients’ HBV load obtained using the HBcrAg assay was not affected by the absence of hepatitis B e antigen from the serum or the presence of precore mutations in the HBV genome. In patients without anti‐viral drugs, changes in their serum HBcrAg concentration over time corresponded to their HBV DNA concentration. In six additional patients who were later treated with lamivudine, HBV DNA concentration declined more rapidly than their HBcrAg concentration. Three months after treatment commenced, the ratio of HBcrAg: HBV DNA had increased in all six patients (P = 0.031). The HBcrAg assay is a sensitive and useful test for the assessment of a patients HBV load. When monitoring the anti‐viral effect of lamivudine, HBcrAg provides a viral marker which is independent of HBV DNA.

New Enzyme Immunoassay for Detection of Hepatitis B Virus Core Antigen (HBcAg) and Relation between Levels of HBcAg and HBV DNA

ABSTRACT A new enzyme immunoassay specific for hepatitis B virus (HBV) core antigen (HBcAg) was developed. In order to detect HBcAg, specimens were pretreated with detergents to release HBcAg from the HBV virion and disassemble it to dimers, and simultaneously, the treatment inactivated anti-HBc antibodies. HBcAg detected by the assay peaked with HBV DNA in density gradient fractions of HBV-positive sera. The assay showed a wide detection range from 2 to 100,000 pg/ml. We observed no interference from anti-HBc antibody or blood components, but the assay was inhibited by very high concentrations (>1 μg/ml; corresponding to 80 signal/cutoff) of HBeAg. When the cutoff value was tentatively set at 4 pg/ml, all healthy control (HBsAg and HBV DNA negative, n = 160) and anti-hepatitis C virus-positive (n = 55) sera were identified as negative. HBcAg concentrations correlated very closely with HBV DNA (r = 0.946, n = 145) in 216 samples from 72 hepatitis B patients. In seroconversion panels, HBcAg concentrations changed in parallel with HBV DNA levels. The assay, therefore, offers a simple method for monitoring hepatitis B patients. With a series of sera during lamivudine therapy, HBV DNA levels fell sharply and the HBcAg concentration also decreased, but the change in HBcAg was smaller and more gradual. The supposed mechanism of these changes and their clinical significance are discussed.

De novo infection of hepatitis B virus in patients with orthotopic liver transplantation: Analysis by determining complete sequence of the genome

De novo infection of hepatitis B virus (HBV) occurs after liver transplantation from donors with HBV markers that suggest past infection. In the present study, the complete nucleotide sequences of HBV derived from a donor and recipients were determined to determine the clinical and virological characteristics. A total of 57 donor‐recipient pairs, which underwent living‐related orthotopic liver transplantation, were enrolled in the present study; all were negative for HBsAg before transplantation. HBV DNA was tested in serum, liver tissue, and peripheral blood mononuclear cells (PBMCs) by the polymerase chain reaction (PCR). The nucleotide sequence of HBV was determined based on PCR products and the phylogenetic analysis. De novo infection of HBV was found in 3 of the 57 recipients. Anti‐HBc was positive in all donors of 3 recipients with the de novo infection but was positive only in 4 donors of the remaining 54 recipients (P=0.001). HBV DNA was detected in the liver but not in the serum or PBMCs in donor 3 whose recipient developed de novo HBV infection. The nucleotide sequence covering entire genome of HBV (3,215 bases) derived from the liver of donor 3 had a homology of 99.8–100% with that derived from the serum of corresponding recipient 3. The strain of recipient 3 showed the closest association with that of the donor 3 by phylogenetic analysis. Complete sequences from two recipients with de novo HBV infection including recipient 3 conserved the basic organisation of HBV genome. Analysis of the entire nucleotide sequence of HBV genome proved that HBV existed in the liver of the donor with anti‐HBc, and it caused de novo infection in the corresponding recipient. J. Med. Virol. 62:471–478, 2000.

Hepatitis B virus RNA is measurable in serum and can be a new marker for monitoring lamivudine therapy

BackgroundChanges in the serum hepatitis B virus (HBV) RNA level during lamivudine therapy were compared to those in the serum HBV DNA and HBV core-related antigen (HBVcrAg) levels in 24 patients with chronic hepatitis B.MethodsFor measurement of HBV RNA, total nucleic acid was extracted from serum samples and treated with RNase-free DNase I. After cDNA synthesis from extracted RNA, HBV RNA was measured by real-time detection polymerase chain reaction.ResultsThe peak fraction of HBV RNA in serum samples was consistent with peak fractions of HBV DNA and HBV core protein in a sucrose gradient analysis, indicating that HBV RNA was incorporated into virus particles. All levels of HBV DNA, HBV RNA, and HBVcrAg decreased gradually during lamivudine therapy (P < 0.001 for all). The amount of decrease from the start of lamivudine therapy was significantly higher for HBV DNA than for HBV RNA or HBVcrAg during 6 months of lamivudine therapy (P < 0.001 for all). However, a similar difference was not seen between HBV RNA and HBVcrAg levels during that period. The HBV RNA level was significantly correlated (P < 0.001 for all) with levels of HBV DNA and HBVcrAg both at the beginning and 2 months after the start of lamivudine therapy.ConclusionsHBV RNA is detectable in serum in a form indicating incorporation into virus particles, and its serum level might serve as a new viral marker with a significance different from that of HBV DNA in lamivudine therapy.

Relationship between hepatitis C virus infection and schistosomal liver disease: not simply an additive effect

Background. To study the association, clinical sig-nificance, and impact of hepatitis C virus (HCV) co-infection in patients with schistosomal liver disease (SLD). Methods. A total of 240 patients with chronic liver diseases encountered consecutively were enrolled in the study. Fifty volunteer blood donors were enrolled as controls. HCV antibody determination (enzyme-linked immunosorbent assay), qualitative and quantitative HCV RNA assay (reverse transcriptase polymerase chain reaction), and HCV genotyping (line probe assay) were performed. Results. Twenty-eight patients had SLD alone, 60 had both SLD and chronic hepatitis C (CH-C), 120 had CH-C alone, and 32 had other liver diseases. The positivity rates for HCV antibody (76% vs 20%; P < 0.001) and HCV RNA (59% vs 10%; P < 0.001) were significantly higher in the patients with SLD (n = 88) than in the volunteer blood donors (n = 50). Complications of liver cirrhosis were more common in patients with concomitant SLD and CH-C than in those with either SLD or CH-C alone. The mean levels of alanine aminotransferase (77 ± 42 vs 93 ± 55 IU/l; P = 0.049) and HCV RNA concentrations (3.5 ± 1.0 vs 4.2 ± 1.0 log copy/ml; P < 0.001) were significantly lower in patients with concomitant SLD and CH-C than in those with CH-C alone. HCV genotype 4 predominated in both these groups (93% and 98%). Conclusions. SLD in Egypt is significantly associated with HCV infection, with the predominance of genotype 4. Concurrent HCV infection and SLD result in much more severe liver disease than that seen with either disease alone. However, the activity of HCV infection seems to be partially suppressed in patients with SLD.

Fulminant hepatitis after allogenic bone marrow transplantation caused by reactivation of hepatitis B virus with gene mutations in the core promotor region

Abstract:  Under immunosuppressive conditions after hematopoietic stem cell transplantation (HSCT), even if hepatitis B virus (HBV) antigen is negative but hepatitis B surface antibody (HBsAb) or hepatitis B core antibody (HBcAb) is presented, HBV reactivates and sometimes causes fulminant hepatitis. However, it remains unclear which patients will develop fulminant hepatitis, or whether fulminant hepatitis is caused by host‐related factors or by virus‐related factors. A 30‐yr‐old man with a history of aplastic anemia since 3 yr of age underwent allogenic BMT, when HBsAb and HBcAb were positive but HBs antigen (HBsAg) was negative. The donor was negative for HBsAg, HBsAb and HBcAb. After transplantation, the patient was complicated by acute graft‐vs.‐host disease (GVHD), cytomegalovirus infection, intestinal thrombotic microangiopathy and aspergillus colitis. Chronic GVHD was well controlled by FK506 and prednisolone. Twenty months after transplantation, the patient was admitted with general fatigue and liver dysfunction and was found to be positive for HBsAg and HBeAg. His serum HBV‐DNA level was >8.8 log of the genome equivalent (LGE)/mL. Therefore, he was diagnosed as having hepatitis B caused by HBV reactivation and 100 mg/d lamivudine treatment was started. However, jaundice and hepatic failure deteriorated and became fatal. On analysis of the HBV‐DNA, two adjacent gene mutations in the core promoter region (T1762/A1764) were detected. Increased replication of the mutated HBV might have caused HBV reactivation which progressed to fulminant hepatitis.

Clinical impact of genotype 1 TT virus infection in patients with chronic hepatitis C and response of TT virus to α‐interferon

Background: The relationship between genotype 1 TT virus (TTV) infection and the status of chronic hepatitis C was studied.

Hepatitis B virus core and core-related antigen quantitation in Chinese patients with chronic genotype B and C hepatitis B virus infection.

Background and Aims:  Hepatitis B virus (HBV) core‐related antigen (HBcrAg) and HBV core antigen (HBcAg) assays were developed for the measurement of serum HBV load. The aim of this study was to assess the clinical utility of these assays in Chinese patients with chronic genotype B and C HBV infection.

Prevalence and disease association of TT virus infection in Japanese patients with viral hepatitis

Abstract Prevalence and disease association of the TT virus (TTV) were studied in Japanese patients with various types of viral hepatitis. A total of 317 patients with viral hepatitis were analyzed, and the results were compared to those of 100 apparently healthy controls. TTV DNA in serum was measured by semi-nested polymerase chain reaction. Prevalence of TTV DNA was significantly higher in patients with hepatitis A (36%, 5/14), hepatitis B (35%, 35/101), hepatitis C (61%, 90/148), and non-A-E hepatitis (41%, 22/54) than in healthy controls (12%, 12/100), respectively. In each type of hepatitis, the prevalence did not differ between acute and chronic liver diseases, and did not increase with the complication of hepatocellular carcinoma. The clinical backgrounds did not differ between TTV DNA positive and negative patients, in patients with acute hepatitis or in those with chronic liver diseases. Similarly, no liver function test showed a significantly higher level of in TTV DNA positive patients than in negative ones. In conclusion, TTV infection was highly prevalent in patients with viral hepatitis, especially in those with hepatitis C. TTV was suggested to have a weak pathogenicity (or no pathogenicity), at least when co-infecting with an established hepatitis virus.