Improvements in detection of antibody to hepatitis B core antigen by treating specimens with reducing agent in an automated microparticle enzyme immunoassay.

A fully automated microparticle enzyme immunoassay (EIA), IMx Core, was developed for the detection of antibody against hepatitis B core antigen (anti-HBc). IMx Core sensitivity was less than 0.5 Paul Ehrlich Institut units per ml and was greater than that of the commercial radioimmunoassay (RIA) or EIA, Corab and Corzyme, respectively. Specimens from blood donors and diagnostic and hospital patients, which included individuals with a variety of infectious and immune diseases, were tested in parallel by the IMx Core and EIA. Overall agreement of 99.1% (4,797 of 4,841) was obtained. Prevalence of anti-HBc tested by IMx Core ranged from 1.2% in volunteer blood donors to 9.1% in hospital laboratories. Discordant specimens reactive by IMx Core but negative by Corzyme or Corab resulted from the increased sensitivity of the IMx Core assay, since other hepatitis B markers were usually present. However, most discordant specimens were positive by the EIA or RIA but negative by IMx Core. No other hepatitis B markers could be detected in these discordants, and after addition of reducing agent, these specimens also became negative by EIA or RIA. In clinical trials, 30% (14 of 47) of volunteer blood donors and 8% (9 of 119) of hospital patients testing repeatedly reactive by the EIA had reduction-sensitive (unspecific) anti-HBc reactivity. The reducing agent, dithiothreitol, was added to each specimen automatically in the IMx assay to eliminate these unspecific reactions without significantly affecting anti-HBc reactivity resulting from hepatitis B virus infection as judged by the correlation with other hepatitis B markers.     

Second generation assays for the detection of antibody to HBsAg using recombinant DNA-derived HBsAg

A second generation radioimmunoassay (RIA) and enzyme-linked immunoassay (EIA) for the detection and quantitation of the antibody to hepatitis B surface antigen (anti-HBs) was developed which utilizes recombinant DNA-derived HBsAg (rHBsAg) in place of human plasma derived HBsAg. In these sandwich assays, rHBsAg immobilized on a solid phase was used to capture anti-HBs from the specimen and rHBsAg conjugated to horseradish peroxidase or radiolabeled with 125I was used as a detecting reagent. These rHBsAg-based assays were compared to a commercial radioimmunoassay for anti-HBs detection (AUSAB RIA). For a population of 1711 sera and plasma specimens, 99.2% overall agreement was demonstrated between the recombinant RIA and EIA and 98.6% agreement was observed between the recombinant assays and AUSAB-RIA. The recombinant assays demonstrated equivalent sensitivity and detectability to AUSAB RIA. Most discrepant samples were low-level reactive by AUSAB-RIA, generally less than 10 mIU/ml, and likely represent nonspecific reactivity since no other marker for hepatitis B infection was detected in these samples.     

Serological detection of HBeAg and anti-HBe using automated microparticle enzyme immunoassays.

Fully automated microparticle enzyme immunoassays (EIA) were developed for the detection of HBeAg (IMx HBe) and antibodies against HBeAg (IMx anti-HBe), respectively. Specimens from blood donors, diagnostic and hospital patients and individuals with a variety of infectious and immune diseases were tested both in house and at four clinical sites. The overall agreement between IMx HBe and Abbott HBe RIA/EIA was 99.7% (2985 of 2994) and between IMx anti-HBe and anti-HBe RIA/EIA was 95.8% (2330 of 2432). Almost all anti-HBe discordant specimens (94.1%, 96 of 102) were reactive by IMx anti-HBe but negative by anti-HBe RIA/EIA. off anti-HBe discordant specimens were also reactive for anti-HBc. The IMx anti-HBe assay was 2- to 4-fold more sensitive than the current RIA as determined by serial dilution of anti-HBe reactive specimens. The ability of these IMx assays to detect HBeAg and anti-HBe in 199 HBsAg reactive specimens was also evaluated. 43.7% (87 of 199) and 66.3% (132 of 199) specimens were reactive for HBeAg and anti-HBe by IMx, respectively. Only one specimen was negative for both IMx assays compared to 14 (7.0%) non-reactive for both HBe and anti-HBe RIA. There were 24 specimens (12.1%) positive for both HBeAg and anti-HBe by IMx compared to 1 (0.5%) positive by the corresponding RIAs. This increased detectability of anti-HBe in HBsAg carriers using IMx anti-HBe may result from increased sensitivity for 'free' anti-HBe and/or increased ability to detect anti-HBe in immune complex. IMx anti-HBe also detected more reactives among volunteer blood donor specimens reactive for anti-HBc but negative for HBsAg (55.5%, 86 of 155), compared to RIA (38.7%, 60 of 155). IMx anti-HBe may be useful in confirming prior exposure to HBV in blood screened positive by Corzyme.     

Significance of isolated hepatitis B core antibodies detected by enzyme immunoassay in a high risk population.

Serum samples, which were found positive for anti-HBc and negative for HBsAg and anti-HBs during routine testing with Abbott enzyme immunoassays (EIA), were collected prospectively. The samples were obtained from patients with a high risk of hepatitis B. Further analysis was carried out using radioimmunoassays and tests for additional markers of hepatitis B. 84 of the 203 initially collected samples (41.4%) were found positive for anti-HBs by RIA. Of the 119 samples negative for anti-HBs by RIA, 103 were available for further investigation, and 35 (34.0%) of these were negative for anti-HBc by RIA. This indicates that low sensitivity of the anti-HBs EIA and non-specificity of the anti-HBc EIA may account for about 60% of the cases presenting with isolated anti-HBc at initial testing. Fifty-two samples positive for anti-HBc by RIA, with isolated anti-HBc confirmed after RIA testing for HBsAg and anti-HBs, were examined further: anti-HBe was detected in 16 sera, anti-HDV in one serum and HBV-DNA in 5 sera by PCR. Additional testing of serum samples with isolated anti-HBc is warranted.     

Differential diagnosis of acute viral hepatitis using rapid, fully automated immunoassays

We report the development of three rapid, fully automated immunoassays allowing the differential diagnosis of acute viral hepatitis. These assays detect HBsAg, IgM antibody to hepatitis B core antigen (IgM anti-HBc) and IgM antibody to hepatitis A virus (IgM anti-HAV) using the IMx instrument system. All IMx assays were run in less than 45 minutes and all steps were fully automated including specimen dilution steps. Specimens from blood donors, diagnostic and hospital patients, and individuals with a variety of infectious and immune diseases were tested for IgM anti-HAV (n = 1473) or for IgM anti-HBc (n = 1606) or for HBsAg (n = 9700) by the IMx and commercially available EIA and RIA. Each IMx assay showed 99.8% agreement with current EIA. Reproducibility in all hepatitis IMx assays was significantly better than that observed with manual or semiautomated assays; within-run and between-run % CV ranged from 2.2 to 4.8 and 3.5 to 10.3 respectively. In 29 acute hepatitis B patients studied, HBsAg and IgM anti-HBc were detected in the first available patient bleed collected from 0 to 4 week from the onset of symptoms. IgM anti-HBc persisted at reactive levels in the IMx assay for 1 to 24 weeks (mean 12.1 +/- 5.3 weeks) after the patient presented with symptoms. In individuals exposed to hepatitis A, IgM anti-HAV was detectable by IMx by 40 days post exposure (average 33.5 days) and IgM had declined to unreactive levels in IMx for all patients by from 3 to 6 months post exposure. These data demonstrate the use of these rapid IMx assays for differentiation of acute hepatitis A and B.     

Enzyme immunoassay for anti-hepatitis B core (HBc) immunoglobulin G1 and significance of low-level results in competitive assays for anti-HBc

An enzyme immunoassay (EIA) for anti-hepatitis B core (HBc) immunoglobulin G1 (IgG1) was compared with a commercial radioimmunoassay (RIA) for anti-HBc antibody (Corab: Abbott Laboratories, North Chicago, Ill.). In parallel tests of 445 consecutive samples, discrepant results were obtained with 2 samples, 1 of which was positive only by the RIA and the other of which was positive only by the EIA for anti-HBc IgG1. In tests of another 192 samples with low blocking activity in the RIA (inhibition range, 90 to 30%), 10 samples gave discrepant results, 5 of which were positive only by the RIA and the other 5 of which were positive only by the EIA for anti-HBc IgG1. Of 12 samples with discrepant results, 11 samples were tested further for anti-HBc IgG3, IgM, and IgA1 by the EIA. Of these, seven samples were positive for anti-HBc IgG1, anti-HBc IgG3, or both. All seven samples were also positive for anti-hepatitis B surface (HBs) antigen. Three samples were negative for anti-HBc IgG1, anti-HBc IgG3, or both but were positive for anti-HBc IgM, anti-HBc IgA1, or both; and one sample was reactive only in the RIA. These four samples were all negative for anti-HBs. Thus, low-level results in the RIA caused by anti-HBc IgM, anti-HBc IgA, or both reflect the unspecific activation of immature B lymphocytes that is not related to previous exposure to hepatitis B virus (HBV). In contrast, the presence of anti-HBc IgG1, anti-HBc IgG3, or both indicates differentiated anti-HBc IgG-producing plasma cells and previous exposure to HBV, as was also shown by the presence of anti-HBs. On class and subclass determination for confirmation of positivity for anti-HBc in 19 serum samples, which was identified by screening of blood from 1,343 donors by a competitive EIA (Hepanostika; Organon), 9 samples with positive results, all low level, did not indicate previous exposure to HBV. It was concluded that determination of classes and subclasses of anti-HBc provides a tool for discriminating positive anti-HBc results not caused by HBV exposure.     

Development and Technical and Clinical Validation of a Quantitative Enzyme-Linked Immunosorbent Assay for the Detection of Human Antibodies to Hepatitis B Surface Antigen in Recipients of Recombinant Hepatitis B Virus Vaccine

Pending removal from the market of a commercial assay (the AUSAB [Abbott Laboratories] enzyme immunoassay [EIA]) for the determination of antibodies to hepatitis B surface antigen (HBsAg), a new in-house quantitative enzyme-linked immunosorbent assay (ELISA) to measure antibodies against HBsAg (anti-HBs) was developed (anti-HBs in-house). Specific anti-HBs antibodies were sandwiched between the precoated HBsAg ad and ay subtypes purified from plasma from hepatitis B virus (HBV) human carriers and the recombinant HBsAg adw2 subtype tagged with horseradish peroxidase. The assay was calibrated against the 1st International Reference Preparation for anti-hepatitis B immunoglobulin (lot 1977-W1042). Analytical sensitivity and the limit of quantitation were estimated at 0.43 mIU/ml and 2.0 mIU/ml, respectively. Overall reproducibility was 11.86%, and accuracy was estimated to be 94.89%. More than 4,000 samples from seven clinical trials were tested with the anti-HBs in-house assay and compared to results generated with AUSAB EIA and AUSAB radioimmunoassay (RIA). During the technical validation, the anti-HBs in-house assay was compared to the AUSAB RIA as a reference (n = 919). Overall assessment of concordance and Deming''s regression analysis were performed. The coefficient of correlation between the AUSAB RIA and anti-HBs in-house assay was 0.9815 with a slope of 0.9187. The overall agreement between anti-HBs in-house and AUSAB RIA was 97.61%, considering the clinical cutoffs at 3.3 mIU/ml and 1.0 mIU/ml for the respective assays. From a clinical perspective, seroprotection rates and anti-HBs geometric mean antibody concentrations for individual studies calculated with either the in-house assay or the reference assays were similar. Conclusions of individual studies were confirmed. The performance characteristics of the in-house assay are acceptable. There is no evidence that use of the new assay would lead to different clinical conclusions from the reference method.Hepatitis B infection is a global health problem but most acutely affects developing countries (16). Currently there is no effective therapy against hepatitis B, whose disease spectrum ranges from asymptomatic disease to chronic liver diseases, including cirrhosis and hepatocellular carcinoma. Prevention of the illness through vaccination remains the method of choice for its control and eradication. Active immunization against hepatitis B infection can be achieved using vaccines containing either inactivated hepatitis B virus (HBV) surface protein (HBsAg) physicochemically purified from plasma from HBV human carriers or recombinant surface antigen produced by transfer of the S gene of HBV coding for HBsAg to an appropriate plasmid that is then inserted into the desired expression vector. The recombinant vaccine manufactured by GlaxoSmithKline Biologicals (GSK) is produced in yeast and is antigenically similar to plasma-derived HBsAg (4). Clinical studies of this recombinant vaccine either formulated as a single-component vaccine (Engerix-B; trademark of GSK) or formulated in combination with other antigens such as hepatitis A vaccine (Twinrix; trademark of GSK) or pediatric diphtheria-tetanus-pertussis-based vaccines (such as Infanrix hexa and Tritanrix HepB; trademarks of GSK) have proven its efficacy and immunogenicity (5).To date, commercial assays from Abbott Laboratories have been used at GSK to quantify the immune response to HBV vaccines in terms of antibodies against HBsAg (anti-HBs). However, since these assays are no longer commercially available in Europe, GSK has developed an in-house assay with adequate technical and clinical performance to ensure long-term supply of an assay with consistent quality. This paper describes the development, technical validation, and the clinical assessment of the new anti-HBs in-house assay.     

Detection of total antibody against hepatitis A virus by an automated microparticle enzyme immunoassay.

A fully automated microparticle enzyme immunoassay, IMx HAVAB, was developed for the detection of antibody against hepatitis A virus (anti-HAV). In the IMx HAVAB assay which is run on the IMx instrument, 24 tests are completed in less than 45 minutes. IMx HAVAB sensitivity was 18-25 World Health Organization U/l and was more sensitive than the commercial RIA or EIA, HAVAB and HAVAB EIA, respectively. Specimens from blood donors, diagnostic and hospital patients and individuals with a variety of infectious and immune diseases were tested in parallel with IMx HAVAB and RIA or EIA. Overall agreement of 99.9% (2118/2121) was obtained. Prevalence of anti-HAV tested by IMx ranged from 12.3% in volunteer blood donors in St. Louis to 64.3% for hospital patients in New York City. Discordant specimens were reactive by IMx HAVAB but borderline negative by EIA or RIA, due to the better sensitivity of the IMx assay. IMx HAVAB detected both IgM and IgG subclasses of anti-HAV. Serial bleeds from six intravenous drug users with acute HAV infection were tested over 8 months for the presence of anti-HAV. At all time points, patients were strongly reactive for anti-HAV (titers greater than 1/1000). Anti-HAV titers rose during the first 20 weeks after presentation of symptoms and then declined with time.     

Long-term follow-up of Hepatitis B Surface antibody levels in subjects receiving universal Hepatitis B vaccination in infancy in an area of hyperendemicity: correlation between radioimmunoassay and enzyme immunoassay

The aims of the present study were to determine (i) the long-term immunogenicity and the decay rate of hepatitis B virus (HBV) surface antibody (anti-HBs) from universal hepatitis B vaccination at infancy for a healthy population in an area of hyperendemicity and (ii) whether the anti-HBs levels measured by enzyme immunoassay (EIA) were closely correlated with those assayed by radioimmunoassay (RIA) methods during long-term monitoring. A total of 1,337 apparently healthy children (696 boys and 641 girls) who were vaccinated against HBV at infancy and monitored for anti-HBs annually from 7 to 16 years of age entered the study. Serum samples were analyzed for anti-HBs by RIA at 7 to 15 years of age and were also analyzed by EIA at 13 to 16 years of age. Antibody titers were quantified in mIU/ml by EIA as well as by the ratio of the count in the sample to the count for a negative control (S/N) by RIA. In non-boosted children, the average decay of anti-HBs from 7 to 16 years of ages indicated that approximately 20% of the geometric mean titer decays per year. There was a good correlation between serum anti-HBs levels measured by the RIA and the EIA methods (r=0.91; P<0.0001). An equation for RIA to EIA level conversion was established: log EIA titer=-0.12+ (1.31 . log RIA S/N). The anti-HBs titers measured by EIA correlate well with the S/N assayed by RIA. The annual decay rate of the log anti-HBs level may help in planning booster immunizations for hypo-responders or individuals at risk in adolescence.     

The diagnosis of acute viral hepatitis A or B by microparticle enzyme immunoassay.

The traditional approach to the diagnosis of viral hepatitis has been to collect a serum sample and to test it for the presence of hepatitis B surface antigen (HBsAg), IgM to the core of HBV (anti-HBc IgM) and IgM to HAV (anti-HAV IgM) by solid phase radio- or enzyme immunoassays. Microparticle enzyme immunoassay technology (IMx-Abbott Laboratories) has been introduced as an automated carousel system for the detection of these markers. A side-by-side, blinded comparison of IMx to current IA was performed for HBsAg on 659 specimens submitted from March to July 1990, of which 72 (10.8%) were positive by AUSRIA (Abbott RIA for HBsAg) and 2 of these were discordant in IMx. Both were near the cutoff and by confirmatory testing one was positive and the other negative. Forty three percent (25/58) of frozen stored sera tested for anti-HBc IgM, by IMx, were positive by EIA (Corzyme M). One specimen near the cutoff was negative by EIA but weakly positive by IMx. Anti-HAV IgM was found in 21.8% (46/211) of sera with 100% correlation by IMx. Thus IMx had the following percent sensitivies and specificities: HBsAg; 98.6, 99.9; anti-HBc IgM; 100, 99.9; anti-HAV IgM; 100, 100. The test set-up times for the 3 markers in the IMx were similar to the RIA and EIA. The turnover time was 45 min for a full IMx carousel compared to: AUSRIA-short incubation (4 h), or long incubation (14 h); Corzyme M-short (4.75 h) or long (20 h); anti-HAV IgM (23 h).(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-Term Follow-Up of Hepatitis B Surface Antibody Levels in Subjects Receiving Universal Hepatitis B Vaccination in Infancy in an Area of Hyperendemicity: Correlation between Radioimmunoassay and Enzyme Immunoassay

The aims of the present study were to determine (i) the long-term immunogenicity and the decay rate of hepatitis B virus (HBV) surface antibody (anti-HBs) from universal hepatitis B vaccination at infancy for a healthy population in an area of hyperendemicity and (ii) whether the anti-HBs levels measured by enzyme immunoassay (EIA) were closely correlated with those assayed by radioimmunoassay (RIA) methods during long-term monitoring. A total of 1,337 apparently healthy children (696 boys and 641 girls) who were vaccinated against HBV at infancy and monitored for anti-HBs annually from 7 to 16 years of age entered the study. Serum samples were analyzed for anti-HBs by RIA at 7 to 15 years of age and were also analyzed by EIA at 13 to 16 years of age. Antibody titers were quantified in mIU/ml by EIA as well as by the ratio of the count in the sample to the count for a negative control (S/N) by RIA. In nonboosted children, the average decay of anti-HBs from 7 to 16 years of ages indicated that approximately 20% of the geometric mean titer decays per year. There was a good correlation between serum anti-HBs levels measured by the RIA and the EIA methods (r = 0.91; P < 0.0001). An equation for RIA to EIA level conversion was established: log EIA titer = −0.12 + (1.31 · log RIA S/N). The anti-HBs titers measured by EIA correlate well with the S/N assayed by RIA. The annual decay rate of the log anti-HBs level may help in planning booster immunizations for hyporesponders or individuals at risk in adolescence.     

The value of screening blood donors for antibody to hepatitis B core antigen.

Rapid counter-immunoelectrophoresis (CIE) and radioimmunoassay (RIA) methods for detecting antibody to hepatitis B core antigen (anti-HBc) were used to screen nearly 8000 blood donors, including 919 prisoners. The prevalence of anti-HBc in prisoner donors (3.4%) was significantly higher than that in other donors (0.7%). The three HBsAg positive donors in the series were all anti-HBc positive and, of the other 73 anti-HBc positive donors, 62 had antibody to HBsAg (anti-HBs). Two panels of control sera, including 155 HBsAg positive samples, were tested by CIE for anti-HBc: 149 of the 155 were anti-HBc positive. Of the six negative samples, four were HBsAg positive only by RIA. One of the panels, containing 16 weakly HBsAg positive samples, was available for anti-HBc testing by RIA. Fifteen of the samples were positive and the other was slightly reactive. Donor sera that gave unconfirmable reactions in initial CIE tests were invariably negative when tested by RIA. The RIA was a more sensitive and specific test for anti-HBc than CIE. The ways in which anti-HBc screening could meet the needs of blood transfusion centres are discussed. We suggest that, in areas of low prevalence, it has a role as a rapid confirmatory test of HBV infection and as a means of identifying those potentially infectious donations in which HBsAg cannot be detected.     

Vaccination against hepatitis B virus at the Lyon Pasteur Institute. A seven-year evaluation]

Results of immunization against hepatitis B among Pasteur Institute staff members are reported. Prior to immunization, 439 subjects were tested for hepatitis B virus (HBV) markers, including HBs antigen, anti-HBs antibody, and anti-HBc antibody (Ausria, Ausab, Corab assays; Abbott). Forty-seven subjects tested positive for anti-HBs antibody. 317 subjects negative for all the HBs markers studied were given three intramuscular doses of Hevac B (Pasteur vaccins) at one-month intervals. Anti-HBs antibodies were assayed after the third injection with the following results: mean titer, 1,454 mIU/ml, standard deviation, 5,349 mIU/ml, and range, 4 to 41,100 mIU/ml. Anti-HBs titers above 10 mIU/ml were found in 879.4% of subjects. Non-responders and weak responders (anti-HBs titer under 10 mIU/ml) were given a fourth dose of vaccine. Ultimately, after the last (third of fourth) injection 97.6% of subjects had protective antibody titers. No case of HBV infection was seen during the seven-year follow-up period.     

Significance of isolated anti-HBc seropositivity by ELISA: implications and the role of radioimmunoassay.

Hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) are excellent markers for HBV infection and its immunity. The significance of isolated antibody to HBV core antigen (anti-HBc) seropositivity is not certain. To elucidate this, sera from 638 Chinese adult subjects, aged 18-52 years, seronegative for both HBsAg and anti-HBs, were tested for anti-HBc. Fifty-one (8%) were found to have an isolated anti-HBc seropositivity by ELISA, and all were negative for IgM-anti-HBc. The anti-HBc persisted in all subjects who attended follow-up for hepatitis B vaccination (n = 48) for a period of 8 months. These 48 subjects received 3 doses of hepatitis B vaccine (HB-VAX, 10 micrograms or 20 micrograms) at 0, 1, and 6 months: 72.9% developed a primary anti-HBs response (suggestive of a false-positive anti-HBc seropositivity), 4.2% developed an anamnestic or secondary anti-HBs response, and 22.9% did not develop an anti-HBs response. Increasing the cutoff point of the ELISA or reconfirmation with radioimmunoassay (RIA) reduced only a minor half of the false positives. This low specificity of anti-HBc ELISA/RIA, together with the high rate of anti-HBs response to hepatitis B vaccine, indicates that subjects with isolated anti-HBc seropositivity should be included in vaccination programs.     

A chemiluminescent, microparticle-membrane capture immunoassay for the detection of antibody to hepatitis B core antigen

A chemiluminescent, microparticle-membrane capture immunoassay (CLIA/MMC) for the detection of antibody to hepatitis B core antigen (anti-HBc) is described. The assay utilizes recombinant hepatitis B core antigen coupled to carboxylated latex microparticles. Human polyclonal IgG anti-HBc labelled with acridinium competes with antibody in the sample for a limited number of binding sites on the solid phase. After a 40 min incubation at 40 degrees C, the reaction mixture is transferred to a glass fiber capture membrane and washed. A chemiluminescent signal is produced by addition of alkaline peroxide and is quantitated on a semi-automated reader as described. The CLIA/MMC assay was compared with standard EIA and RIA procedures (Corzyme and Corab, respectively, Abbott Laboratories, North Chicago, IL). Assay sensitivities were RIA greater than CLIA/MMC greater than EIA. A population of 200 normal blood donors showed nearly identical distributions with the CLIA/MMC and RIA (mean = 11% inhibition, SD = 13% for both), compared with the EIA (mean = 13% inhibition, SD = 15%). With a selected plasma population (n = 307), the CLIA/MMC immunoassay showed an excellent correlation (r = 0.94) with both the EIA and RIA procedures. Association of anti-HBc reactivity near assay cutoffs with antibody to hepatitis B surface antigen suggested relative specificity in the order RIA greater than CLIA/MMC greater than EIA. The CLIA/MMC procedure, which can be readily automated, provides a non-istopic alternative to current EIA testing with performance more nearly equivalent to RIA.     

Comparison of two testing methods to determine hepatitis B surface antibody response to hepatitis B vaccine among health-care workers

Because of variations in reported seroconversion rates and to compare enzyme-linked immunoassay (EIA) and radioimmunoassay (RIA) methods to assess hepatitis B vaccine response, hepatitis B surface antibody (anti-HBs) was tested in 116 of 174 high-risk hospital employees enrolled in a hepatitis B vaccine program. All individuals were vaccinated with three injections of Heptavax-B, 1.0 ml containing 20 micrograms of HBsAg intramuscularly in the deltoid. The same lot of appropriately stored vaccine was used. Of the 41 individuals tested within zero to six months postvaccination, 35 (85%) and 38 (93%) were positive by EIA and RIA, respectively. Of the 75 individuals tested 7-24 months postvaccination, 61 (81%) and 71 (95%) were positive by EIA and RIA, respectively. Results of EIA tests performed at two laboratories were similar. Of 109 individuals positive by RIA, 13 did not have protective antibody levels. In contrast, of 96 individuals positive by EIA, only one did not have a protective antibody level. RIA may be a more sensitive test for anti-HBs, but a positive EIA result correlates better with protective antibody levels.     

乙肝核心抗体阳性供肝在肝移植中的应用

背景：现已经证实使用anti-HBc(+)供肝会使移植后乙肝复发的风险,但anti-HBc(+)供肝的应用明显缓解了供肝的相对匮乏。 目的：分析应用anti-HBc(+)供肝移植后乙肝复发风险及有效的预防措施。 方法：应用计算机检PubMed数据库中1994-01/2009-12关于anti-HBc(+)供肝文章,在标题和摘要中以“Hepatitis B core antibody; donor;liver transplantation”为检索词进行检索。选择与anti-HBc供肝相关文章。初检得到109篇文献,根据纳入标准选择48篇文章进行综述。 结果与结论：HBsAg(+)患者接受anti-HBc(+)供肝移植术后乙肝复发率为11%,生存率为67%~100%,与HBsAg(+)受者接受anti-HBc(-)供肝相似。HBsAg(-)受者接受anti-HBc(+)供肝总体感染率为19%,其中未感染过乙肝受者移植术后乙肝感染率为48%,感染过乙肝受者后感染率为15%。未感染乙肝与感染过乙肝受者移植后采取有效预防措施后感染率分别为3%,12%。采用HBIG、拉米夫定、联合用药的移植后感染率分别为19%,2.6%,2.8%。提示,采用anti-HBc(+)供肝做为供体是安全的,尤其是用在HBsAg(+)、anti-HBc(+)、anti-HBs(+)受者。而HBsAg(-)受者移植后接受拉米夫定可以有效复发乙肝感染。     

Enzyme-linked immunosorbent assay for detection of immunoglobulin M antibody to hepatitis B core antigen.

An enzyme-linked immunosorbent assay for detection of specific immunoglobulin M (IgM) antibodies against the core antigen of the hepatitis B virus (anti-HBc IgM) is described. The interference of IgM rheumatoid factor was evaluated quantitatively. In the anti-HBc IgM test, the rheumatoid factor gave false-positive results when the concentration exceeded 20 IU/ml. The rheumatoid-positive sera were disclosed by a control and retested for anti-HBc IgM after absorption of rheumatoid factor with latex particles aggregated with human IgG. In five of seven selected patients with acute hepatitis B followed to biochemical and clinical recovery, anti-HBc IgM was present transiently until antibodies against hepatitis B surface antigen (anti-HBs) appeared. Two patients had persistent anti-HBc IgM during the follow-up period. Four patients with hepatitis B surface antigenemia and progression to chronic liver disease did not clear their anti-HBc IgM in the period of observation (11 to 24 months). Anti-HBc IgM could not be demonstrated in 223 of 225 Danish blood donors. The two donors found positive for anti-HBc IgM also had anti-HBs. Twenty patients with acute A or non-A non-B hepatitis were negative for anti-HBc IgM. The enzyme-linked immunosorbent assay for anti-HBc IgM described here has a high specificity and sensitivity. The diagnostic relevance needs further evaluation, including quantitation of anti-HBc IgM, but the results presented indicate that anti-HBc IgM may be helpful in differentiating between prior and recent or ongoing hepatitis B infection.     

Low-dose vaccination against hepatitis B in children: one-year follow-up

Six hundred forty-three children, negative for markers of hepatitis B virus (HBV) infections, were given three X 2-micrograms doses of Merck, Sharp and Dohme (MSD) plasma derived hepatitis B vaccine (H-B-Vax) at monthly intervals. Twelve months after the first dose of vaccine, antibody to hepatitis B surface antigen (anti-HBs) was detected in 89% of children by radioimmunoassay (RIA) and in 83% by enzyme immunoassay (EIA). Seroconversion rates and anti-HBs titres were significantly greater in 1-4-year-olds than in older children (p less than 0.01). Eighteen children with no anti-HBs or other markers of HBV at this time were given 10 micrograms of vaccine and tested one month later. Seventeen developed anti-HBs, 12 at levels consistent with an anamnestic response. Forty-nine HBV-marker-negative children seroconverted for antibody to hepatitis B core antigen (anti-HBc) in the 8-month period before or the 12-month period following vaccination. Forty-six of these children were positive for anti-HBs, and one has been confirmed as a chronic carrier of hepatitis B surface antigen (HBsAg). Three cases of clinical hepatitis B in children have been seen in the community since the vaccination programme began. Two of these were amongst the estimated 5% of children who were not vaccinated. The third was in a vaccinee and occurred 4 1/2 months after the last dose of vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)     

乙型肝炎病毒母婴阻断长期效果的随访研究

目的观察乙型肝炎病毒母婴阻断长期效果,探讨HBsAg阳性孕妇生产儿童发生慢性HBV感染的相关影响因素。方法随访和收集于2004--2006年在北京地坛医院出生的HBsAg阳性母亲所生,并在出生时进行200单位乙肝免疫球蛋白（HBIG）注射和经过乙肝疫苗10μg,0、1和6个月的完整免疫接种程序的儿童静脉血,采用Abbott微粒子化学发光法检测其HBsAg、抗-HBs抗体、抗-HBc抗体,分析母婴阻断和乙肝疫苗接种的长期效果及其影响因素。结果收集和调查306名儿童年龄3—6（4．84）岁,其母亲生产时HBeAg阳性198人,HBeAg阴性92人。10（3．27％）名儿童发生慢性HBV感染。除慢性HBV感染者外,其余296名儿童,20．27％抗-HBs〈10mlU／ml;44．26％抗-HBs≥10—100mlU／ml;27．03％抗-HBs≥100～1000mlU／ml和8．45％抗-HBs≥1000mlU／m,抗-HBs保护率为79．73％（236／296）。抗-HBc阳性率为7．43％（22／296）。10例感染儿童的母亲生产时HBeAg均为阳性,HBVDNA均在10。拷贝／ml以上,其中8例超过10^8拷贝／ml。结论在进行乙肝疫苗加HBIG注射的HBV母婴传播阻断措施下,HBV母婴阻断失败和慢性H13V感染发生在HBeAg阳性和高病毒载量产妇所生婴儿,在有效阻断后仍需进行抗HBs监测并加强免疫接种。