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【Objective】 To investigate asymptomatic infection of hepatitis B virus(HBV) among hepatitis B vaccinated donors in Shenzhen, and analyze its serological and molecular characteristics. 【Methods】 The HBsAg ELISA positive blood samples of blood donors born after 1992 were collected. HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were further detected by Roche electrochemiluminescence immunoassay (ECL). BCP/PC and S regions were amplified by Nested-PCRs, HBV DNA quantification were adopted by qPCR simultaneously, and the sequences were also analyzed. 【Results】 A total of 46 632 blood samples of donors(31 612 males and 15 020 females) from December 2020 to January 2022 collected, and 99 samples with HBsAg ELISA positive were screened out. After tested by ECL, Nested-PCRs, and real-time fluorescence PCR, 61 were confirmed HBsAg positive, with the positive rate at 0.13% (61/46 632), including 49 males (0.16%, 49/31 612) and 12 females (0.08%, 12/15 020). The HBsAg positive rate of males was higher than that of females (P<0.05). 50 out of 61 sequences for S region were obtained. By phylogenetic analysis, there were 46 cases of type B (92%, 46/50, 38 males and 8 females), 4 cases of type C (8%, 4/50, 3 males and 1 female). The high frequency mutations observed in S region were N40S (8/46,17.39%), G44E (7/46,15.22%), Q129H/R(6/46,13.04%), Y161F/S(7/46, 15.22%), V179A(4/46,8.70%), S53L(2/4,50%), C69T(2/4,50%) and I126S/T(2/4,50%), including the immune escape mutations Q129R and T/I126A/N/S/T. 【Conclusion】 Hepatitis B vaccination can significantly reduce the positive rate of HBsAg and increase the safety of blood transfusion. The high frequency immune escape mutations have become a potential risk of blood safety, and need to be further explored.
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【Objective】 In an effort to prevent transfusion-transmitted hepatitis B infection, universal HBsAg screening, HBsAg+ MP nucleic acid test(NAT) for HBV and HBsAg + individual(ID) NAT were analyzed for cost-effectiveness. 【Methods】 On the basis of screening data and the documented parameter, the number of window period infections, chronic infections and occult infections was constructed, and cost-benefit analysis was conducted. 【Results】 Of 132 208 donations, the yield rate of ID NAT for HBsAg-/DNA+ (0.11%) was significantly higher than HBsAg+ MP NAT(0.058%). Furthermore, the predicted preventing transfusion transmitted HBV cases by ID NAT is 1.25 times as that by MP-6 NAT, so did the benefits. The cost-benefit of the three screening models were 1∶63.6、1∶28.6 and 1∶53.4. 【Conclusion】 Universal HBsAg in combination with ID HBV NAT screening was the most effective among all screening strategy. It is necessary to applied HBsAg and ID HBV NAT screening for the safety of blood transfusion.
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【Objective】 To investigate NAT non-reactive results implicated in HBsAg ELISA reactive voluntary blood donors in Shenzhen. 【Methods】 HBsAg ELISA+ but NAT-blood samples were collected, and HBsAg was further retested by TRFIA, Roche ECLIA and neutralization test. HBV DNA of individual donation was detected by commercial Roche MPX and Uultrio Elite, and virus nucleic acid was extracted via 2.5 mL. Molecular characterizations of HBsAg+ /NAT-samples were determined by quantitative polymerase chain reaction(qPCR) and nested PCR amplifification of the precore and core promoter regions and HBsAg(S) region. HBV serological markers were detected, and the samples with suspicious results were followed up and detected by multi-assay. 【Results】 Among 67 602 samples, 73(0.11%) HBsAg ELISA+ and NAT-blood samples were enrolled in the study. 15(20.5%, 15/73) were confirmed HBsAg+ by TRFIA, ECLI and five alternative DNA assays, and the other 2(2.7%, 2/73) were further identified as HBsAg+ by follow-up study. In 17 confirmed HBsAg+ samples, the viral loads ranged undetectable to 378 IU/mL, with the median of 10.1 IU/mL. Weak correlation was found between HBsAg and HBV DNA load(R2=0.394 4). 【Conclusion】 Some Hepatitis B virus infected blood samples may miss even with different HBsAg assays. Multi-assays with high sensitivity should be combined for blood screening to ensure blood safety..The inconsistent results should be followed up and further tested for hepatitis B serological markers to assist the confirmation.
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【Objective】 To investigate HBV infection with low level of HBsAg and nucleic acid testing(NAT) non-reactive results in blood donors, and analyze molecular characteristics. 【Methods】 Low level HBsAg but NAT-nonreactive samples were collected and tested for HBsAg by Abbott chemiluminescent microparticle immunoassay (CMIA)., HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were further detected by Roche electrochemiluminescence immunoassay(ECLI). BCP/PC and S regions were also amplified by Nested-PCRs and qPCR for HBV DNA quantity were adopted simultaneously. 【Results】 Of 100 363 donations, 60(0.054%) low level HBsAg and NAT-nonreactive blood samples were enrolled the study. In which, 54/60(90%) and 57/60(95%) were WanTai HBsAg ELISA and DiaSorin HBsAg ELISA reactive respectively. Of 33 cases genotyped, genotype B were 87.9%( 29/33), including adw2 96.6%(28/29) and adw1 3.4%(1/29), C was observed in 4(12.1%) with sero-type adrq+. Mutations in S gene of genotype B such as Q101R, Q129H, T131I, M133L/T, F134L, G145R, V168A, L175S and V177A were observed as notable mutations, which can affect HBsAg diagnosis. A high frequency mutation C1799G(87.5%, 21/24)were detected in BCP/PC and would reduce the replication of virus. The median viral load measured by qPCR was 49.6(0~628)IU/mL. 【Conclusion】 A small part of donations with low-level HBsAg and NAT-nonreactive can not be deferred by one isolated ELISA screening assay. It is necessary to apply more sensitive and specific HBsAg assays and NAT in blood screening, and improve the ability to detected mutants.
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OBJECTIVE To investigate and analyze the kinetics of serological marks and virus load of the follow-up blood donors. METHODS The quantitation of HBV DNA of 6 HBsAg negative and DNA positive blood donors was detected by Roche PCR Monitor,and the donors were genotyped and traced by serological tests. RESULTS(Three of 6 follow-up) donor samples were seroconverted after more than 40 days follow-up study.The viral loads were with range of(35-1.8)?10~4 copies/ml,1 of 6 donors had acute infection,the peak load was(1.8?10~4 copies/ml),3 of 6 were with lower level HBV carrier with fluctuating viral load ranged 100-500 copies/ml.One donor had decreasing viral load,when HBsAg converted to positive,virus wasn′t detected.The last one had fluctuating virus load below(100 copies/ml),intermittently falling below the threshold of the assay. CONCLUSIONS It is necessary to implement HBV DNA detection for blood screening,and further strengthen the safety of blood transfusion.
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Objective To establish the entirely automatic method of nucleic acid amplification testing (NAT) for blood screening and to study the feasibility of NAT.Methods Using entirely automated extraction method to extract nucleic acid , amplified and detected by Roche COBAS AMPLICOR system,evaluating the sensitivity and efficacy.Results The 95% limits of HBV DNA, HCV RNA/HIV-1 RNA tests by automation system were 38.9,16.4IU/ml and 20.4 copies/ml,95% Confidence Intervals were [21,323], [10.5,342] and [12,300] respectively.8 of 16 512 donations were PCR for HBV DNA positive,the DNA positive rate was 0.048%.7/8 donations were Anti-HBc positive,The last one was also converted positive.No positive HCV RNA and HIV RNA was detected. 3/6 following up samples seroconverted.Conclusions The entirely automatic system can be applied in blood screening.
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Objective To establish fully automated sample pooling, nucleic acid extraction, amplification and detection method for HBV DNA testing, and investigate the seroconversion and genotype in HBV DNA positive donors. Methods Individual donor plasma samples serologically negative for HBV were pooled by STAR2000 sampling processor with a size of 24. Nucleic acid were automatically extracted by MPLC simultaneously, amplified and detected by Roche COBAS AMPLICOR system. The sensitivity of detection was determined by international standard. HBV DNA positive donors were genotyped and followed up by serological tests. Results The 95% detection limit for this automated HBV DNA testing system was 38.9IU/ml,with 95% confidence interval (21323),eight out of 16512 specimens were PCR positive for HBV DNA,with a positive rate of 0.049%. Three of the 8 DNA positive donors were genotype C,2 genotype B, 1 genotype D,and the other 2 uncertain。Six of the eight HBV DNA positive donors were followed up, and three of them seroconverted。 Conclusion Fully automated HBV DNA detection method can be applied in blood screening,and will further increase the safety of blood supply.
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Objective To perform NAT testing on samples negative for HBsAg, anti-HCV and anti-HIV by ELISA, and to learn how many infected blood samples could be missed by ELISA tests.Methods Pooling the donor samples by STAR2000 sampling processor and extracting nucleic acid automatically, HBV DNA, HCV RNA and HIV-1 RNA were amplified and detected by Roche COBAS AmpliScreen TM HBV、HCV V2.0 和HIV-1 V1.5 systems. Samples of 8 donors with negative HBsAg but positive HBV DNA were tested by COBAS HBV MONITOR TM for quantitative determinations. HBsAg confirmation tests were done every 2 weeks by ABBOTT Murex HBsAg V3.Results A total of 16320 ELISA negative donor samples were tested and 8 samples were HBV DNA positive. The missing rate was 0.49‰. No HCV RNA and HIV-1 RNA were detected. Those 8 donor samples, negative for HBsAg but positive for HBV DNA,were all positive for HBcAb by ABBOTT,and 3 of them were positive for HbeAb Low serum HBV DNA loads, in the range of 102~103 copies/ml, were found in the 8 donor samples. HBsAg confirmations were performed and one donor became HBsAg positive after 18 weeks.Conclusion The results show that there is 0.49‰ missing rate of HBV with HBsAg screening by ELISA. HBcAb screening or NAT may be warranted in blood donor screening to limit HBV transmission through blood transfusion.The reason for missing HBV positive samples by ELISA could be occult HBV infection.