ABSTRACT
HCV genotypes have been documented in clinical practice. The aim of this study was to determine the replication priority of different HCV genotypes in a Chinese HCV positive cohort. Serum samples from 491 apparently healthy Chinese blood donors testing positive for HCV antibodies and naive to antiviral drug therapy were tested. Genotyping analysis showed that genotypes 1b and 2a were predominant and accounted for 77.6% of the HCV infections. Among the genotype groups, individuals infected with genotype 2a had an HCV RNA viral load (10(8) copies/mL) about 200-fold (lg, 2.3) greater than those infected with other genotypes (10(4)-10(5) copies/mL) indicating a replication priority of genotype 2a. However, there was no correlation between HCV genotype and antibody response suggesting that the amplification advantage of genotype 2a results from a favorable interaction with the host cellular environment. In conclusion, HCV genotypes 1b and 2a are the predominant genotypes in China and genotype 2a possesses a significant replication priority compared with the other genotypes. This suggests the existence of host cellular factors that may act as drug-targets for entirely clearing HCV infection in the future.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.