Measurements in international units of antibody to hepatitis B surface antigen(anti-HBs) after immunization with a yeast-derived, subtype adr hepatitis B vaccine are considerably different between chemiluminescent immunoassay (CLIA) and chemiluminescent enzyme immunoassay (CLEIA)

The worldwide consensus of the minimum protective anti-HBs level against HBV infection is 10 mIU/mL on assays standardized by the World Health Organization (WHO) reference preparations. To investigate whether this value could be applied to recipients of yeast-derived recombinant HB vaccine containing the major surface protein of subtype adr (Bimmugen, Astellas Pharmaceutical, Tokyo), we compared anti-HBs measurements between chemiluminescent immunoassay (CLIA) (Architect Ausab, Abbott Japan, Tokyo) and chemiluminescent enzyme immunoassay (CLEIA) (Lumipulse Forte, Fujirebio, Tokyo) in given serum samples obtained from the vaccinees. The vaccine and the two assay methods are currently in a wide use in Japan. The study included 300 medical students who completed a standard vaccination course (0, 1 and 6 months). Serum samples obtained 1 month or 13 months after completing the vaccination were simultaneously tested for anti-HBs by CLIA and CLEIA. In 147 samples with quantifiable values on both CLIA and CLEIA (10 to 1000 mIU/mL) the geometric mean titer on CLEIA (225.0 mIU/mL) was significantly higher than that on CLIA (94.5 mIU/mL) (p < 0.0001). Of 26 subjects with CLIA measurements below 10 mIU/mL, 15 samples (57.7%) showed CLEIA measurements more than 10 mIU/mL. Thus, in the subtype adr-vaccinees CLEIA demonstrated considerably high serum anti-HBs measurements compared to CLIA and discordance in determining critical anti-HBs level of 10 mIU/mL was observed in more than half the samples. This suggests that the minimum HBV-protective anti HBs titer of 10 mIU/mL is difficult to be introduced to Japan where subtype adr-HB vaccines or -HBV infection are prevalent, unless characteristics of assay methods are carefully evaluated.     

Distribution of anti-HBs levels in Korean adults

Exact titration of anti-HBs with mIU/mL unit is necessary in evaluating the success of HBV vaccination or in making a decision to increase the dose of HBV vaccination. Data of distribution of anti-HBs titers can contribute to cutting of public health costs by reducing unnecessary HBV booster doses. Moreover, anti-HBc is also an important marker for differentiation of vaccination-induced anti-HBs from infection-acquired anti-HBs. However, not much study about these subjects has been done in Korea. So we evaluated anti-HBs associated with anti-HBc and vaccination history. HBsAg and anti-HBs tests were done in 1,465 cases. The positive rates of HBsAg and anti-HBs were 4.5% and 74.6%, respectively. Anti-HBs positive rate was higher in the vaccinated group than that in the non-vaccinated group. The rates of anti-HBs positive cases with lower titers (10-< 100 mIU/mL) were 31.9%, while cases with higher titers (> or = 100 mIU/mL) were 68.1%. This suggested about 70% of anti-HBs-positive Korean adults (about 53% of the general adult population) have long-lasting immunity against HBV infection and may not require booster doses of HBV vaccination for a long time. Anti-HBs titers in the vaccine-induced anti-HBs group were higher than those in the infection-acquired anti-HBs group. No statistical differences were noted between male and female or among age groups. 25.7% of the HBsAg (-)/anti-HBs (-) group showed anti-HBc positive and HBV-DNA was detected in 11.1% among HBsAg (-)/anti-HBs (-)/anti-HBcAb (+) cases. Further study about post vaccination anti-HBs titer decay in Korean should be performed to help cut vaccination costs.     

Hepatitis B vaccine in infants from an endemic area: long-term anti-HBs persistence and revaccination

Persistence of anti-HBs in 156 Senegalese infants immunized with hepatitis B vaccine was studied for periods ranging from 2 to 6 years after booster dose administration. Six years after the booster dose, 90.4% of the infants had detectable anti-HBs antibodies, with 78.1% having titers higher than 10 mIU/ml. The geometric mean titer was 60 mIU/ml. Females showed higher anti-HBs values than males. In a group of 11 infants who received no booster dose, anti-HBs antibodies were detectable 7 years after the first dose. However, the geometric mean titer was lower (26 mIU/ml). Revaccination (56 infants) led to an increase of the geometric mean titer to 469 mIU/ml 2 months later. These results show that a booster injection every 5-6 years should provide adequate protective anti-HBs levels in infants.     

Long-term anti-HBs antibody persistence and immune memory in children and adolescents who received routine childhood hepatitis B vaccination

This paper presents data from two studies that evaluated 5-y and 10-y persistence of antibodies against hepatitis B (HBV) surface antigen (anti-HBs) and immune response to an HBV vaccine challenge in children and adolescents who had received three doses of a HBV vaccine in infancy as part of routine clinical practice [NCT00519649/NCT00984139]. Anti-HBs antibody concentrations ≥ 10 mIU/ml persisted in 83.3% (95% confidence interval [CI]: 78.5–87.5) and 78.3% (95% CI: 73.1–83.0) of subjects aged 7–8 y and 12–13 y, respectively 5–10 y after infant vaccination. One month postchallenge dose, 98.2% (95% CI: 95.9–99.4) and 93.7% (95% CI: 90.2–96.2) of subjects in the two age groups, respectively had anti-HBs antibody concentrations ≥ 100 mIU/ml. Overall, 99.6% (95% CI: 98–100) and 97.2% (95% CI: 94.5–98.8) of subjects aged 7–8 y and 12–13 y mounted an anamnestic response to the HBV challenge dose, which was well-tolerated. Healthy children aged 7–8 y and adolescents aged 12–13 y received three doses of a monovalent pediatric HBV vaccine (10 μg of HBsAg) before 18 mo of age. Serum samples collected before and one month post-HBV vaccine challenge dose were tested for anti-HBs antibody concentrations. Safety assessments were made for the HBV vaccine challenge dose. A three-dose childhood HBV immunization regimen induced persistence of antibodies against HBV infection for 10 y, up to adolescence. This vaccination regimen also conferred long-term immune memory against HBV as evidenced by the strong anamnestic response to the HBV vaccine challenge, despite waning anti-HBs antibody levels.     

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.     

Application of a Newly Developed High-Sensitivity HBsAg Chemiluminescent Enzyme Immunoassay for Hepatitis B Patients with HBsAg Seroclearance

We modified and automated a highly sensitive chemiluminescent enzyme immunoassay (CLEIA) for surface antigen (HBsAg) detection using a combination of monoclonal antibodies, each for a specific epitope of HBsAg, and by improving an earlier conjugation technique. Of 471 hepatitis B virus (HBV) carriers seen in our hospital between 2009 and 2012, 26 were HBsAg seronegative as determined by the Abbott Architect assay. The Lumipulse HBsAg-HQ assay was used to recheck those 26 patients who demonstrated seroclearance by the Abbott Architect assay. The performance of the Lumipulse HBsAg-HQ assay was compared with that of a quantitative HBsAg detection system (Abbott Architect) and the Roche Cobas TaqMan HBV DNA assay (CTM) (lower limit of detection, 2.1 log copies/ml) using blood serum samples from patients who were determined to be HBsAg seronegative by the Abbott Architect assay. Ten patients had spontaneous HBsAg loss. Of 8 patients treated with nucleotide analogues (NAs), two were HBsAg seronegative after stopping lamivudine therapy and 6 were HBsAg seronegative during entecavir therapy. Eight acute hepatitis B (AH) patients became HBsAg seronegative. Of the 26 patients, 16 were HBsAg positive by the Lumipulse HBsAg-HQ assay but negative by the Abbott Architect assay. The differences between the two assays in terms of detectable HBsAg persisted over the long term in the spontaneous loss group (median, 10 months), the NA-treated group (2.5 months), and the AH group (0.5 months). In 9 patients, the Lumipulse HBsAg-HQ assay detected HBsAg when HBV DNA was negative by the CTM assay. HBsAg was also detected by the Lumipulse HBsAg-HQ assay in 4 patients with an anti-HBs concentration of >10 mIU/ml, 3 of whom had no HBsAg escape mutations. The automatic, highly sensitive HBsAg CLEIA Lumipulse HBsAg-HQ is a convenient and precise assay for HBV monitoring.     

国内外九种乙型肝炎基因工程疫苗的免疫效果研究

目的 比较各种乙型肝炎（以下简称乙肝）基因工程疫苗的人体免疫学特点及效果。方法 应用美国ＭＳＤ、Ａｍｇｅｎ公司、日本熊本、法国巴斯德、阿根廷莱茵美州公司五个国外厂家及北京、长春、深圳康泰三个国内厂家的酿酒酵母、哺乳动物细胞、牛痘毒重组、甲基营养型酵母４个表达系列、１２个批次的乙肝基因工程疫苗免疫７１５名６～１０岁小学生,使用放射免疫法（ＲＩＡ）、美国Ｂｂｂｏｔｔ试剂检测免后不同时间的抗－ＨＢｓ。结果 四个系列的乙肝基因工程疫苗免疫人体后安全有效;国产疫苗免后抗体高峰期出现在首针免后７个月;哺乳动物细胞疫苗的批间稳定性较好;酿酒酵母疫苗在峰值后的抗体水平下降幅度较小;含量１０μｇ／支的疫苗较５μｇ／支者显示出有持久的优势。甲基营养型酵母疫苗是国内首次观察;含量１０μｇ／支的疫苗较５μｇ／支者显示出有持久的优势。甲     

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.     

Antibody detection and kinetics of antibody production during early stages of immunization with hepatitis B virus vaccine

Antibodies to influenza virus and human immunodeficiency virus are detectable in B cells during the early stages of the immune response, prior to their occurrence in plasma. To investigate similar phenomena in a model of immunization against hepatitis B virus (HBV) infection, medical students in Ghana were screened for HBV markers, HBV surface (HBs) antigen (HBsAg), and HBV core antibodies (anti-HBc). Consenting volunteers, 24 of whom were seronegative (susceptible) and 2 of whom were positive for anti-HBc (prior infection), were vaccinated on day 0, day 40, and 6 months. Two sets of 10 blood samples, sequentially collected at intervals of 2 days following each immunization on days 0 and 40, were processed into B-cell lysates and plasma. Solid-phase HBsAg coated on microtiter plates for enzyme immunoassay or nitrocellulose membranes for dot blot assay was used to detect anti-HBs activity by an indirect antiglobulin assay. A commercially procured sandwich immunoassay was used, along with an enzyme-linked immunosorbent assay and a dot blot assay, for the detection of anti-HBs in B-cell lysates and plasma. Following the first injection of vaccine, a single sample of B-cell lysate collected between 5 and 21 days revealed anti-HBs in 18/21 subjects with no plasma antibodies detectable by sandwich immunoassay. After the booster dose was injected on day 40, a single sample of B-cell lysate collected between 44 and 49 days showed anti-HBs in 16/19 subjects, and this was accompanied by plasma antibodies in 8 subjects. In contrast, between 8 and 13 days, both subjects with prior HBV infection showed anti-HBs in B-cell lysates and plasma. Thus, primary immunization with the HBV vaccine appears to transiently elicit low-affinity anti-HBs in B-cell lysates into plasma.     

Immunogenicity of a yeast-recombinant hepatitis B vaccine in high-risk children

Horizontal transmission of hepatitis B virus (HBV) from illicit drug users to their contacts, including young children, can be prevented by active immunization against HBV. Yeast-recombinant hepatitis B vaccines are now available for this purpose, but their potential efficacy in such high-risk contacts has not yet been evaluated. Therefore we gave 20 mcg of a recombinant yeast-derived hepatitis B vaccine to 38 children who were at high risk for HBV infection because they had been institutionalized in a community for drug users in which 8.7% of the occupants are carriers. After third dose of vaccine (at 0, 1, and 6 months), all children had anti-HBs responses with titers of 10 mIU/ml or more, with 81% showing responses greater than 1,000 mIU/ml. At 12 months, the percentage of anti-HBs-positive children was 100%, and the percentage of children with anti-HBs higher than 1,000 mIU/ml was 56%. None of the children developed HBV infection during follow-up. Hence the recombinant vaccine was immunogenic, with percentages of seroconversion and anti-HBs titers comparable with those attained in other categories of high-risk children with plasma-derived vaccines.     

成人及新生儿乙肝疫苗免疫后15年内表面抗体水平的变化

目的描述和比较北京市15岁及以上人群(以下简称成人)及新生儿乙肝疫苗接种后的15年内抗体水平,为北京市乙肝疫苗接种策略提供参考。方法 2013年8月至2014年2月采用多阶段整群随机抽样方法在北京市1岁以上人群中抽取6 705人进行乙肝血清学流行病学调查,选择其中完成3针基因重组乙肝疫苗接种且没有进行加强免疫的成人和新生儿为研究对象,描述和比较成人和新生儿接种乙肝疫苗后15年抗-HBs阳性率和抗-HBs滴度变化。结果共纳入符合入组标准的新生儿和成人分别为463和129人。基于中国目前15~59岁人群自限性感染率估计为30%,成人接种后0~4、5~9和10~15年的抗-HBs阳性率仍可分别保持在58.6%、62.5%和48.4%,呈现平稳下降的趋势;对应的抗-HBs滴度中位数分别为288.8、120.6和62.6 m IU/m L。新生儿接种人群3个时间段的抗-HBs阳性率分别为83.3%、47.3%和43.5%;抗-HBs滴度中位数分别为71.8、8.9和6.7 m IU/m L;成人接种乙肝疫苗后5~15年的抗-HBs滴度及阳性率均高于新生儿。结论成人和新生儿接种乙肝疫苗15年内可获得良好的保护。     

Acute hepatitis B viral infection in a patient with anti-HBs.

We report a patient with antibody to hepatitis B surface antigen (anti-HBs) but no antibodies to other hepatitis B virus components, who developed acute symptomatic type B hepatitis. The possible explanations for this unusual serological pattern are 1) the antibody-positive status, which developed against only a subdeterminant of hepatitis B surface antigen (HBsAg), arose naturally or as the result of cross-reaction with a variety of antigens; and 2) seroconversion to anti-HBs occurred in response to surface antigen of a mutant strain of hepatitis B virus (HBV). This anti-HBs positivity, in the absence of antibody to hepatitis B core antigen, does not provide natural immunization against HBV infection, and so is not protective. Individuals who are positive to anti-HBs antibody alone which is not elicited by HBV vaccine, should be vaccinated against possible HBV infection.     

GM—CSF促进乙肝病毒基因疫苗诱导的抗体产生

将构建的编码乙肝病毒PreS2+S蛋白的真核表达质粒注射于C57BL/6小鼠胫前肌内,3d后,在同一部位注射rhGM-CSF。基因疫苗接种2周后,血清中可测到抗-HBs,两月后,抗体水平达到高峰,并保持高水平至少2月以上;肌内注射GM-CSF可提高血清抗-HBs水平,提示GM-CSF可作为基因疫苗的佐剂。     

Performance of the DiaSorin LIAISON anti-HBs II for the detection of hepatitis B surface antibodies: Comparison with the Abbott Architect anti-HBs assay

BackgroundDetection of hepatitis B virus (HBV) surface antibodies (anti-HBs) is required in order to evaluate the response to hepatitis B vaccination and to optimize post-exposure monitoring. The widespread use of vaccines has highlighted the need for accurate and consistent quantification, yielding comparable quantitative results.ObjectivesThis study assessed the adequacy of DiaSorin LIAISON^® anti-HBs II assay in detecting anti-HBs antibodies and determined the correlation with Abbott Architect anti-HBs quantification.Study designAnti-HBs levels were measured in parallel using Abbott and DiaSorin kits on WHO international standard dilutions and 350 routine samples pre-screened with Abbott Architect anti-HBs. Three different serological panels were tested: vaccinated subjects (n = 121); subjects with past HBV infection (n = 109); and subjects with no HBV infection marker (n = 69). Serial dilutions from nine high-titer anti-HBs samples were used to address linearity.ResultsAnti-HBs concentration measured on WHO standard dilutions indicated a good calibration of DiaSorin values against international units, while results for Abbott were below those expected. A strong impact of the dilution matrix used was observed when performing dilutions on high-titer samples. Despite difference in absolute quantification, the overall clinical agreement between the two assays was 96.9%, with strong correlation (r = 0.92) between concentrations and good linearity over the quantification range.ConclusionsThe DiaSorin LIAISON^® anti-HBs II assay shows excellent standardization to the WHO standard and good linearity. The assay is suitable for current clinical laboratory practice.     

Seroprevalence of Hepatitis-B infection amongst Taiwanese university students 18 years following the commencement of a national Hepatitis-B vaccination program

In Taiwan, the nation-wide Hepatitis-B virus (HB) vaccination program was first launched in July 1984 and was directed to those infants born to hepatitis B surface antigen (HBsAg) carrier mothers in Taiwan. From July 1986 onwards, all infants born in Taiwan were immunized against HB. This study examined the HB-infection status amongst students at a Taiwanese university 18 years subsequent to the implementation of universal HB vaccination. A total of 1,969 new university entrants in 2005 were grouped into 1 of 3 distinct birth cohorts according to their HB-vaccination schedule (cohort-1 students born prior to July 1, 1984; cohort-3 students born subsequent to June 30, 1986) and were examined for their serum HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) status. Immunity arising from vaccination was defined as an anti-HBs level 10 mIU/ml. We observed a trend toward a decreasing anti-HBc-positive rate and a decreasing HBsAg carrier rate from, respectively, 26.5 and 8.7% for cohort-1 to 4.7 and 1.7% for cohort-3 students. The prevalence of students featuring seronegativity for all three HB markers increased from 12.3% for cohort-1 to 48.8% for cohort-3 individuals. Amongst the 1,695 subjects revealing seronegativity for HBsAg and anti-HBc, their anti-HBs level was analyzed according to their birth year. The prevalence of students featuring a non-protective anti-HBs level increased from 11.9% for birth-year 1984 individuals to 48.2% for birth-year 1987 students. The introduction of HB vaccine has effectively reduced the transmission of HBV infection in Taiwan, 18 years subsequent to the commencement of the universal HB-vaccination program. A "waning-off" effect of anti-HBs seropositivity acquired from the HB vaccination program has also been observed.     

Multicenter trial on the efficacy of HBIG and vaccine in preventing perinatal hepatitis B. Final report

In an attempt to interrupt perinatal transmission of hepatitis B, 92 infants born to HBsAg carrier mothers (49 to HBeAg-positive mothers, 30 to anti-HBe-positive with abnormally elevated ALT levels, and 13 to HBeAg/anti-HBe-negative mothers) received 0.5 ml/kg BW of HBIG at birth and at 1 month of age. Three IM injections of hepatitis B vaccine were given at 3, 4, and 9 months of life. All babies who were given the three doses of vaccine developed an active anti-HBs response: of these, 53 (62.3%) had antibody titers higher than 1,000 mIU/ml, 29 (34.2%) had levels between 100 and 1,000 mIU/ml, and the other three (3.5%) were below 100 mIU/ml. At the end of the 2-year follow-up, these three poor responders became anti-HBs negative, whereas the others still had antibody. All but three babies were protected by HBIG plus vaccine treatment. Two chronic HBV infections occurred within 6 months of life presumably because the babies were already infected when prophylaxis started. The third baby became an HBsAg carrier at 9 months of age in spite of a previous response to the vaccine. Simultaneous presence of HBsAg of y specificity and anti-HBs (anti-a) was still detectable at 24 months of age. The vaccine was well tolerated. Passive plus active immunization is an effective procedure for preventing perinatally transmitted HBV infection.     

Use of highly sensitive methods of detecting hepatitis B virus markers for studying epidemic foci of hepatitis B

Passive hemagglutination test (PHA) was found to detect HBsAg in the population living outside the hepatitis B virus foci 1.5-fold as frequently as counter immunoelectroosmophoresis technique, and anti-HBs by enzyme immunoassay 14-fold as frequently. As compared with normal population, the contacts in foci had 4-fold higher levels of HBsAg carrier state and twice as high rates of detection of anti-HBs. The total index of HBV infection in foci was 27.7%. The above materials considerably extend the concepts of HBV epidemiology. The regularity of the results obtained indicate the specificity and high sensitivity of PHA and EIA tests and suggests that they be used on a wider scale.     

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.     

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。     

A sensitive chemiluminescent enzyme immunoassay for carbofuran residue in vegetable,fruit and environmental samples

Using the direct competitive chemiluminescent enzyme immunoassay (CLEIA), a rapid, highly selective and sensitive method for carbofuran determination was developed. Several physicochemical parameters such as chemiluminescent sensitiser, assay buffer, blocking substance and working concentration were optimised. Under the optimum conditions, the CLEIA method for carbofuran determination was generated successfully. The detection sensitivity of the IC₅₀ value was 4.2 ng/mL at a practical working concentration ranging from 0.4 to 50 ng/mL, and the limit of detection (LOD) for carbofuran was 0.5 ng/mL. Recoveries of carbofuran spiked into vegetable, fruit and environmental samples were determined by CLEIA after sample matrix effect testing. Finally, the confirmation test between CLEIA and LC-MS/MS was finished. The results showed that CLEIA method had higher sensitivity than enzyme-linked immunosorbent assay method, and the LOD of a variety of samples reached the carbofuran's maximum residue limit value laid down by Codex Alimentarius Commission.