Blood donation screening for hepatitis B virus markers in the era of nucleic acid testing: are all tests of value?

Characterization of mutations in hepatitis B virus DNA isolated from Japanese HBsAg-positive blood donors in 2021 and 2022

Missense mutations in certain small envelope proteins diminish the efficacy of antibodies. Consequently, tracking the incidence and types of vaccine-escape mutations (VEMs) was crucial both before and after the introduction of universal hepatitis B vaccination in Japan in 2016. In this study, we isolated hepatitis B virus (HBV) DNA from 58 of 169 hepatitis B surface antigen (HBsAg)-positive blood samples from Japanese blood donors and determined the nucleotide sequence encoding the small envelope protein. DNA from six (10%) of the samples had VEMs, but no missense mutations, such as G145R, were detected. Complete HBV genome sequences were obtained from 29 of the 58 samples; the viral genotype was A1 in one (3%), A2 in three (10%), B1 in nine (31%), B2 in five (17%), B4 in one (3%), and C2 in 10 (34%) samples. Tenofovir-resistance mutations were detected in two (7%) samples. In addition, several core promoter mutations, such as 1762A>T and 1764G>A, and a precore nonsense mutation, 1986G>A, which are risk factors for HBV-related chronic liver disease, were detected. These findings provide a baseline for future research and highlight the importance of ongoing monitoring of VEMs and drug resistance mutations in HBV DNA from HBsAg-positive blood donors without HBV antibodies.

Evaluating the cost-effectiveness of low-level HBV DNA screening in occult hepatitis B infection donors: A study from Shandong Blood Center, China

OBJECTIVE

This study aimed to assess the efficacy of individual-donation nucleic acid testing (ID-NAT) in detecting occult hepatitis B virus infection (OBI) among anti-HBc positive blood donors, compared to minipool nucleic acid testing (MP-NAT).

METHODS

The present study analyzed data from the Shandong Blood Center in China during the period from January 2018 to June 2022, where HBsAg-negative blood donors were screened using the 6-sample minipool nucleic acid testing (6-sample MP NAT) method. NAT-positive samples underwent subsequent anti-HBc and anti-HBs testing. Approximately 5000 samples that passed the nucleic acid mixing test were randomly selected for anti-HBc testing, and over 100 anti-HBc positive samples underwent individual donor nucleic acid testing (ID-NAT). Any HBV DNA positive samples detected by ID-NAT were subsequently confirmed using alternative nucleic acid testing methods.

RESULTS

Among 220,445 HBsAg-negative blood donors, the positivity rate of HBV DNA detection using the 6-sample minipool nucleic acid testing (MP NAT) method was found to be 0.031% (69/220,445). Of the 67 HBV DNA positive samples, 55 (82.09%) and 25 (37.31%) were found to be positive for anti-HBc and anti-HBs, respectively, using the supplementary chemiluminescent microparticle immunoassay (CMIA). Among the 4797 HBsAg-negative/MP NAT-negative samples, 909 (18.95%) tested positive for anti-HBc. Further NAT testing was performed on 164 arbitrarily selected anti-HBc-positive/MP HBV DNA-negative samples, revealing a HBV DNA positivity rate of 1.22% (2/164).

CONCLUSION

Using individual donation nucleic acid testing can significantly increase the detection rate of occult hepatitis B virus infection in anti-HBc-positive blood donors, resulting in a detection rate of 0.22% (1.22 × 0.1895). This rate is 8.10 times higher than the detection rate achieved by mixed testing methods (0.031%) [calculated as (0.22 + 0.031)/0.031]. Therefore, it is recommended to perform single HBV DNA testing on anti-HBc-positive blood donors, discard plasma with weakly positive or negative anti-HBs but positive anti-HBc, or avoid transfusing anti-HBc-positive plasma to recipients with weakly positive or negative anti-HBs to prevent HBV infection.

Occult and active hepatitis B virus detection in donated blood in São Paulo, Brazil

BACKGROUND

The present study determined the HBV antigen, antibody, and DNA status in blood donations deemed to be HBV positive. Individuals with an occult HBV infection (OBI), defined as being positive for HBV DNA but negative for HBV surface antigen (HBsAg), as well as those with active infection (HBsAg-positive), were identified and characterized.

STUDY DESIGN AND METHODS

From a total pool if 198,363 blood donations, we evaluated in a cross-sectional study, 1106 samples that were positive in screening tests for antibody to HBV core antigen (HBcAb), HBsAg, and/or HBV DNA by nucleic acid testing (NAT-HBV). The presence of genetic variants in the HBV pol/S gene in individuals with an active HBV infection was also determined.

RESULTS

OBIs were detected in six of 976 samples (0.6%) that were positive only for HBcAb. The rate of HBV active infection was 0.024% (48/198,363) and there was a predominance of HBV sub-genotype A1 (62.2%, 28/45), followed by D3 (17.8%, 8/45). Mutations in the S gene were found in 57.8% (26/45) and immune escape mutations in 37.8% (17/45) of active HBV-infected donors. Among them, T123N, G145A, and D144G high-impact immune escape mutations were identified.

CONCLUSION

Highly sensitive molecular tests improve the capacity to detect OBIs. When NAT is performed in pooled samples, HBcAb test has value in the detection of donors with OBI and improves transfusion safety. Mutations in the S gene are frequent in HBsAg-positive blood, including those associated with diagnostic failure and vaccine escape mutations.

Performance characteristics of the high sensitivity Alinity i & ARCHITECT HBsAg Next Qualitative/Confirmatory assays

Despite improvement in vaccinations, Hepatitis B remains a major health concern due to the difficulty of prevention even in low endemic areas such as Europe. In this report we describe the performance characteristics of the new HBsAg Next Qualitative and HBsAg Next Confirmatory assays designed for blood screening and diagnostic purposes on the Alinity i and ARCHITECT fully automated systems. The new assays were evaluated in comparison to the ARCHITECT HBsAg Qualitative II and Confirmatory assays on seroconversion, analytical sensitivity, and mutant panels along with testing of over 400 clinical positive samples demonstrating excellent improvements in sensitivity. Additionally, specificity was shown to be improved with testing of over 6000 donors and 240 diagnostic specimens. Overall, the Alinity i & ARCHITECT HBsAg Next assays have taken a step forward in improving the detection of Hepatitis B virus.

THE IMPACT OF POSITIVE ANTI-HBC MARKER ON PERMANENT DEFERRAL OF VOLUNTARY BLOOD DONORS IN EASTERN CROATIA AND ESTIMATION OF OCCULT HEPATITIS B VIRUS INFECTION RATE

Recently an increase has been reported in the number of HBV transmissions from anti-HBc positive blood donors that were repeatedly negative in HBsAg and nucleic acid testing using the most sensitive tests available. The aim of the study was to show the effect of anti-HBc antibody testing performed in 2006 on permanent deferral of voluntary blood donors (VBDs), and to estimate occult hepatitis B infection (OBI) rate in this population after the introduction of mandatory molecular testing in the 2013-2016 period. More than 30,000 blood donations collected during the 2005-2007 period and more than 14,000 VBDs having donated blood during the 2013-2016 period after the introduction of molecular testing from eastern Croatia were included in the study. Serologic testing was performed with HBsAg assay throughout the study period, and anti-HBc assay was only performed in 2006. As part of the confirmatory algorithm testing, all HBsAg positive and unclear results were tested with molecular tests. Anti-HBc prevalence among VBDs in 2006 was 1.5%, with a rate of 1:197, whereas HBsAg prevalence was stable from 2005 to 2007 (0.04%, 0.1% and 0.1%, respectively). The calculated OBI rate from 2013 to 2016 was 1:30,250. Ten of 161 (12.4%) VBDs had serologic anti-HBc-only pattern. Anti-HBc testing in 2006 resulted in statistically more deferrals of VBDs compared to 2005 and 2007, and to the rest of Republic of Croatia. The strategy of universal anti-HBc testing of VBDs in addition to the existing HBsAg and molecular screening could be an additional measure to prevent HBV transmission by blood and blood components.

Anti-HBc prevalence among Croatian blood donors in a 14-year period (2004-2017): Assessment of trends, risks and need for implementing routine testing

OBJECTIVES

The anti-HBc prevalence over a 14-years period (2004-2017), trends, infectivity, residual risk, and need for testing in blood donors (BD) of the Croatian Institute of Transfusion Medicine were assessed.

MATERIAL AND METHODS

Anti-HBc was tested in 19,969 BD serum samples collected in 2004 (N=7561), 2013 (N=7318) and 2017 (N=5090). All serums were initially screened for HBsAg, anti-HCV, HIV Ag/Ab, and anti-TP. 2013 and 2017 samples were also tested by ID-NAT.

RESULTS

Over a 14-years period, the anti-HBc prevalence significantly decreased among Croatian BD (5.24% in 2004, 2.56% in 2013, and 1.32% in 2017). Similarly, the prevalence of anti-HBc-only profiles decreased from 0.62% in 2004, 0.25% in 2013, and 0.21% in 2017. The 4-time decreasing trend was observed in all age groups of BD from 2017 but mostly among repeat donors (5.90% to 1.38%). First-time donors showed no significant difference in anti-HBc prevalence probably due to their younger age (<29 years) and HBV vaccine status. However, similar anti-HBs carriage rates (80.56%, 87.57%, and 82.09%) were reported in anti-HBc positive donors over the study period. HBsAg and HBV DNA were not detected. No OBI infection was found in the study despite an OBI frequency of 1:10,900 donations previously reported in Croatia. A HBV decreasing residual risks of 68, 88, and 12 per million donations were estimated for years 2004, 2013, and 2017, respectively.

CONCLUSION

Anti-HBc testing is an additional measure of preventing HBV infection by transfusion. Implementation of anti-HBc testing will result in the deferral of 1.3% BD and should be supported by cost-benefit analyses.

Anti-HBc screening - is it worth the effort? Results of a 10-year surveillance programme covering more than 30 million donations in Germany

BACKGROUND AND OBJECTIVES

Antibodies to hepatitis B core antigen (anti-HBc) testing were added to hepatitis surface antigen (HBsAg) screening in Germany in 2006 to prevent hepatitis B virus (HBV) transmissions by chronically infected donors. We report the results of a national surveillance of anti-HBc-reactive and HBsAg-negative donations and assess the resulting gain in blood safety and the donor loss.

MATERIALS AND METHODS

Donations were tested for anti-HBc, and if reactive, by sensitive individual donation nucleic acid testing (ID-NAT) and for antibodies to HBsAg (anti-HBs). Data from the national anti-HBc surveillance from 2006 to 2015 determined the proportion of anti-HBc-reactive donations stratified for donor type, sex, anti-HBs concentration and NAT-positivity. Donor loss due to anti-HBc-reactive results was quantified.

RESULTS

Of 31 562 556 donations screened, 70 671 were anti-HBc reactive but HBsAg negative (0.22%). The proportion of repeat donors with these test results decreased significantly from 0.25% in 2007 to 0.08% in 2015. In the entire study period, 82 HBV-NAT-positive donations were identified. Of these, 47 donations were only identified by ID-NAT. A total of 54 203 anti-HBc-reactive units were discarded either due to possible infectiousness (NAT positive or anti-HBs concentration <100 IU/l) or because no further testing was performed.

CONCLUSION

Anti-HBc screening has improved blood safety in Germany. HBV-NAT-positive donations were identified after ID-NAT was triggered by the initial reactive anti-HBc result. The observed loss of donations was sustainable for maintaining an adequate blood supply in Germany.

What Is Needed to Eliminate Hepatitis B Virus and Hepatitis C Virus as Global Health Threats

Hepatitis B virus (HBV) and hepatitis C virus (HCV) cause 1.3 million deaths annually. To prevent more than 7 million deaths by 2030, the World Health Organization set goals to eliminate HBV and HCV, defined as a 90% reduction in new infections and a 65% reduction in deaths, and prevent more than 7 million related deaths by 2030. Elimination of HBV and HCV is feasible because of characteristics of the viruses, reliable diagnostic tools, and available cost-effective or cost-saving interventions. Broad implementation of infant immunization against HBV, blood safety, and infection-control programs have greatly reduced the burden of HBV and HCV infections. To achieve elimination, priorities include implementation of HBV vaccine-based strategies to prevent perinatal transmission, safe injection practices and HCV treatment for persons who inject drugs, and testing and treatment for HBV- and HCV-infected persons. With sufficient capacity, HBV and HCV elimination programs can meet their goals.

An ultra-sensitive Abbott ARCHITECT® assay for the detection of hepatitis B virus surface antigen (HBsAg)

BACKGROUND

Critical to the identification of HBV infection and the prevention of transfusion transmitted disease is the sensitive and accurate detection of Hepatitis B virus surface antigen (HBsAg). Improvements in HBsAg assay sensitivity approaching the performance of nucleic acid testing (NAT) are essential to further reduce the detection window for acute HBV infection in regions where NAT is not widely available.

OBJECTIVES AND STUDY DESIGN

An improved HBsAg assay on the fully-automated Abbott ARCHITECT^® platform was developed to improve sensitivity, mutant and genotype detection.

RESULTS

The analytical sensitivity of the improved prototype assay is 5.2 mIU/ml, which is 3.86- to 14.54-fold more sensitive than comparator assays based on the WHO International Reference Standard. The enhanced sensitivity was also demonstrated with 27 HBV seroconversion panels, detecting more panel members (191 of 364) vs. the ARCHITECT^® Qual I (144), Qual II (160) and PRISM^® (148) HBsAg assays. Further, the assay detected 7 of 12 HBV DNA positive/HBsAg negative samples, and detected all evaluated mutants and genotypes with higher sensitivity than the comparator assays. The improvement in sensitivity did not diminish assay specificity, attaining 100% (95% CI, 99.97-100%) on 10,633 blood donors.

CONCLUSIONS

An Abbott ARCHITECT^® HBsAg assay with clinical performance approaching that of mini-pool NAT (approximately 100 copies/ml was developed. The assay has superior HBsAg mutant and genotype detection and specificity, all of which are important for the diagnosis and management of HBV infection.

Occult Hepatitis Infection in Transfusion Medicine: Screening Policy and Assessment of Current Use of Anti-HBc Testing

HBV still represents a global risk factor in transfusion medicine. The residual risk of HBV is not limited to pre-seroconversion window period but it extends to donors with occult HBV infection (OBI) characterized by the presence of HBV DNA in liver and by the absence of the virus surface antigen. Each country developed an appropriate blood screening policy according to local HBV prevalence, yields of infectious units per different screening methods and cost-effectiveness. We underline the need of maintaining a high level of attention for OBI carrier identification in all blood banks worldwide where the screening procedures are generally based on a combination of both serological markers and nucleic acid amplification test. In this context, markers such as hepatitis B surface antibodies and hepatitis B core antibodies (anti-HBc) might be useful, although the use of this latter is highly debated and still controversial. Our aim is to give an overview on the relevant diagnostic approaches for the routine screening for HBV focusing on the feasibility of anti-HBc testing as precautionary measure in preventing OBI transmission worldwide. In our tailored algorithm, the loss of about 1% of 'anti-HBc only' donors, does not significantly affect the blood supply while improving recipient safety.

Prevalence of Serologic Hepatitis B Markers in Blood Donors From Puebla, Mexico: The Association of Relatively High Levels of Anti-Core Antibodies With the Detection of Surface Antigen and Genomic DNA

BACKGROUND

The hepatitis B virus (HBV) causes chronic hepatitis, hepatic cirrhosis, and hepatocellular carcinoma. Surface antigen (HBsAg) detection is a definitive test that can confirm HBV infection, while the presence of antibodies against the core protein (anti-HBc) suggests either a previous or ongoing infection or occult hepatitis B infection (OBI).

OBJECTIVES

The aim of the present study was to determine the prevalence of anti-HBc and HBsAg in blood donors. Further, the study aimed to estimate the anti-HBc level at which HBV DNA is detected in putative OBI cases, as well as to search for mutations in the "a" determinant associated with the non-detection of HBsAg in serum.

PATIENTS AND METHODS

We conducted a cross-sectional study from 2003-2009. The study included 120,552 blood donors from the state of Puebla, Mexico. Different commercial systems based on microparticles (enzymatic (MEIA) or chemiluminescent (CMIA)) were used to determine the HBsAg and anti-HBc levels. For the detection of HBV DNA, a nested polymerase chain reaction (nested PCR) was used and the genotypes were determined using Sanger sequencing.

RESULTS

Of the 120,552 blood donors, 1437 (1.19%, 95% CI: 1.12 - 1.26) were reactive to anti-HBc, while 82 (0.066%, 95% CI: 0.053 - 0.079) were reactive to HBsAg. Some 156 plasma samples collected in 2009 from anti-HBc-positive/HBsAg-negative blood donors were submitted for HBV DNA detection in a search for probable OBI. Viral DNA was detected in 27/156 (17.3%, 95% CI: 11.5 - 23.1). Our results show an association between HBV DNA or HBsAg and anti-HBc S/CO levels ≥ 4.0. All DNA samples were identified as genotype H and some "a" determinant mutations were identified, although none corresponded to mutations previously reported to hinder the detection of HBsAg by commercial immunoassays.

CONCLUSIONS

We observed that as the anti-HBc levels increase, there is a higher prevalence of the viral protein HBsAg in blood donors. Samples testing positive for HBV-DNA were seen to exhibit a ten-fold higher presence of anti-HBc S/CO ≥ 4 than those with S/CO ≥ 1 and < 4.0, which highlights the relevance of anti-HBc determination in blood donor samples.

Hepatitis B surface antibodies in medical students from a public university in Puebla, Mexico

Although preventable with vaccination, Hepatitis B virus (HBV) infection is a major health concern, with ∼400 million people at risk of developing the chronic form of the disease worldwide. The anti-HBV vaccine consists of a recombinant HBV surface antigen (HBsAg), which induces specific anti-HBs antibodies and confers 95% protection for >20 y. The aim of the present study was to analyze the response to HBV vaccination by measuring anti-HBs antibodies in serum samples from medical students of a public university in Puebla, Mexico. HBV infection markers HBsAg and anti-HBs, were also determined. A total of 201 students were included and vaccination coverage was found at 54%. Overall seropositivity for HBsAg, anti-HBc and anti-HBs determined by ELISA was 0.5%, 1.0% and 47%, respectively. Protective levels of anti-HBs >10 mIU/mL were found in 93.2% of subjects vaccinated with 2 or 3 doses and in 40% of those vaccinated with a single dose; while only 4.8% of unvaccinated subjects were anti-HBs positive. The response to the HBV vaccine was different in each participant, despite similar vaccination scheme. A history of blood transfusion/organ transplant or more than 2 sexual partners was significantly associated with anti-HBc positivity, OR = 399 (p = 0.010) and OR = 19.9 (p = 0.044), respectively. HBV immunization coverage was low in our sample compared with reports from countries with similar HBV prevalence, but anti-HBs in vaccinated individuals were in the expected range. It is important to promote HBV vaccination and awareness among medical students, due to their exposure risk.

Automated Triplex (HBV, HCV and HIV) NAT Assay Systems for Blood Screening in India

This review is confined to triplex nucleic acid testing (NAT) assays to be used on fully automated platform. Around the world, these assays are being used at various transfusion medicine centres or blood banks to screen blood units for HBV, HCV and HIV. These assay systems can screen up to 1000 blood units for HBV, HCV and HIV simultaneously in a day. This area has been dominated by mainly two manufacturers: M/s Gen-Probe-Novartis and M/s Roche Molecular Systems. The triplex NAT assay systems of both manufacturers are licensed by United States Food and Drug Administration. There is not much awareness about the technology and procedures used in these assays. The main objective of this review is to create awareness about the technology and procedure of these assays.

High Prevalence of Hepatitis B Virus Infection in Young Adults in Ternate, Eastern Indonesia

The incidence of hepatitis B virus (HBV) infection has been declining thanks to the universal hepatitis B infant immunization program. Nevertheless, young adults born before the program implementation might have acquired HBV in early childhood or remain susceptible to infection. This study aimed to evaluate hepatitis B epidemiology in asymptomatic young adult population in Ternate, eastern Indonesia. Serum samples of 376 subjects (aged 17-25, mean 19.82 ± 1.69 years; male/female 138/238) were screened for HBV parameters serologically (HBV surface antigen [HBsAg]; its antibody [anti-HBs]; anti-core antigen [anti-HBc]), and molecularly (HBV DNA). HBsAg, anti-HBc, anti-HBs, and HBV DNA prevalence were 15.7%, 36.2%, 24.2%, and 27.9%, respectively, with male predominance. Of all subjects, 13.0% were HBsAg negative with detectable HBV DNA (occult hepatitis B [OHB]), and 56.4% showed negativity for all seromarkers. This population showed high hepatitis B prevalence with substantial occurrence of OHB. However, a high percentage of the population were still susceptible and at risk of HBV infection. This study emphasizes the necessity to improve prevention strategies to screen and manage HBV carriers, including the adoption of catch-up or booster vaccination targeted to young adult populations. Investigations on the roles of host-virus interactions associated with OHB and its implications are warranted.

Molecular mechanisms underlying HBsAg negativity in occult HBV infection

Although genomic detection is considered the gold standard test on HBV infection identification, the HBsAg investigation is still the most frequent clinical laboratory request to diagnose HBV infection in activity. However, the non-detection of HBsAg in the bloodstream of chronic or acutely infected individuals has been a phenomenon often observed in clinical practice, despite the high sensitivity and specificity of screening assays standardized commercially and adopted in routine. The expansion of knowledge about the hepatitis B virus biology (replication/life cycle, genetic variability/mutability/heterogeneity), their biochemical and immunological properties (antigenicity and immunogenicity), in turn, has allowed to elucidate some mechanisms that may explain the occurrence of this phenomenon. Therefore, the negativity for HBsAg during the acute or chronic infection course may become a fragile or at least questionable result. This manuscript discusses some mechanisms that could explain the negativity for HBsAg in a serological profile of individuals with HBV infection in activity, or factors that could compromise its detection in the bloodstream during HBV infection.

The yield of universal antibody to hepatitis B core antigen donor screening in the Netherlands, a hepatitis B virus low-endemic country

BACKGROUND

In the Netherlands, universal antibody to hepatitis B core antigen (anti-HBc) donor screening was introduced in July 2011 to intercept potentially infectious donations slipping through hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA minipool screening (HBV DNA MP6).

STUDY DESIGN AND METHODS

The yield and donor loss were evaluated after the first 2 years of universal anti-HBc donor screening. A total of 382,173 donors were tested for anti-HBc and, if positive, for antibody to HBsAg (anti-HBs). Anti-HBc-reactive donors with anti-HBs of less than 200 IU/L were deferred, but repeat donors were allowed retesting after 6 months if anti-HBs was less than 10 IU/mL. Anti-HBc false positivity was estimated using the crude anti-HBc signal, family name-based ethnicity scoring, and donor follow-up.

RESULTS

Anti-HBc screening identified 13 confirmed or potential HBsAg- and HBV DNA MP6-negative recent HBV infections. In addition, 820 anti-HBc-reactive donors with low anti-HBs titers (<200 IU/mL), potentially harboring occult HBV infection (OBI), were identified and deferred. Overall, 1583 (0.41%) donors were deferred: 1178 (0.31%) during first-time anti-HBc screening, 361 (0.09%) anti-HBc seroconverters, and 44 (0.01%) donors with waning anti-HBs titers. Only 188 of 1583 (12%) deferred donors could be reentered upon retesting. Estimated anti-HBc false positivity was 16%, but varied greatly among anti-HBc-reactive donors with and without anti-HBs (8% vs. 62%).

CONCLUSION

Anti-HBc testing has improved the safety of the Dutch blood supply but its exact yield remains difficult to determine, due to the complexity of confirming anti-HBc reactivity and OBI. In a low-endemic country, donor loss associated with anti-HBc screening is sustainable, but adds to the already considerable list of donor exclusions.

Risk factors for retrovirus and hepatitis virus infections in accepted blood donors

BACKGROUND

Risk factor surveillance among infected blood donors provides information on the effectiveness of eligibility assessment and is critical for reducing risk of transfusion-transmitted infection.

STUDY DESIGN AND METHODS

American Red Cross, Blood Systems, Inc., New York Blood Center, and OneBlood participated in a case-control study from 2010 to 2013. Donors with serologic and nucleic acid testing (NAT) or NAT-only confirmed human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), or serology-confirmed human T-lymphotropic virus (HTLV) infections (cases) and donors with false-positive results (controls) were interviewed for putative behavioral and demographic risks. Frequencies and adjusted odds ratios (AORs) from multivariable logistic regression analyses for each exposure in cases compared to controls are reported.

RESULTS

In the study, 196 HIV, 292 HBV, 316 HCV, and 198 HTLV cases, and 1587 controls were interviewed. For HIV, sex with an HIV+ person (AOR, 132; 95% confidence interval [CI], 27-650) and male-male sex (AOR, 62; 95% CI, 27-140) were primary risk factors. For HBV, first-time donor status (AOR, 16; 95% CI, 10-27), sex with an injection drug user (IDU; AOR, 11; 95% CI, 5-28), and black race (AOR, 11; 95% CI, 6-19) were primary. For HCV, IDU (AOR, 42; 95% CI, 13-136), first time (AOR, 18; 95% CI, 10-30), and a family member with hepatitis (AOR, 15; 95% CI, 6-40) were primary. For HTLV, sex with an IDU (AOR, 22; 95% CI, 10-48), 55 years old or more (AOR, 21; 95% CI, 8-52], and first time (AOR, 15; 95% CI, 9-24) were primary.

CONCLUSIONS

Despite education efforts and risk screening, individuals with deferrable risks still donate; they may fail to understand or ignore or do not believe they have risk. Recipients have potential transfusion-transmitted infection risk because of nondisclosure by donors.

Mini review: current molecular methods for the detection and quantification of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus type 1

The detection of acute human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection is vital for controlling the spread of HIV, HBV, and HCV to uninfected individuals. Considering that these viruses have high replication rates and are undetectable by serological markers, early detection upon transmission is crucial. Various nucleic acid assays have been developed for diagnostics and therapeutic monitoring of infections. In the past decade, rapid and sensitive molecular techniques such as PCR have revolutionized the detection of a variety of infectious viruses, including HIV, HCV, and HBV. Here, we describe two of the most commonly used licensed methods for the detection and quantification of HIV, HCV, and HBV: the cobas TaqScreen MPX (PCR) test and the Tigris System. We used transcription-mediated amplification to review and compare the development and efficiency of these technologies.

Hepatitis B transmission by cell and tissue allografts: How safe is safe enough?

More than 2 million human tissue transplants (bone, tendon, cartilage, skin, cornea, amniotic membrane, stem cells, heart valve, blood vessel, etc.), are performed worldwide every year. Cells and tissues are shared between countries which have different regulations and laboratory equipment and represent a risk of hepatitis B virus (HBV) transmission that has become a global safety concern. While the risk of transfusion-transmitted HBV infection from blood donations has been estimated, the rate of HBV transmission from donors to recipients of allografts is unknown and varies between different tissues. There are various important ways of reducing the transmission risk, but donor screening and donor testing are still the main factors for preventing HBV transmission. HBV detection is included in the routine screening tests for cell and tissue donors. The standard test for preventing transplant-transmitted hepatitis B is the hepatitis B surface antigen. The implementation of methods involving nucleic acid amplification and the new generation of reactives to detect viral antibodies or antigens with an immunoassay, has increased the sensitivity and the specificity of the screening tests. The objective of our research was to review the literature and critically analyse the different steps for avoiding HBV transmission in cell and tissue donors, focusing on the screening tests performed.

Prevalence of hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus and hepatitis E virus as causes of acute viral hepatitis in North India: a hospital based study

CONTEXT

Acute viral hepatitis (AVH) is a major public health problem and is an important cause of morbidity and mortality.

AIM

The aim of the present study is to determine the prevalence of hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and hepatitis E virus (HEV) as causes of AVH in a tertiary care hospital of North India.

SETTINGS AND DESIGN

Blood samples and clinical information was collected from cases of AVH referred to the Grade I viral diagnostic laboratory over a 1-year period.

SUBJECTS AND METHODS

Samples were tested for hepatitis B surface antigen, anti-HCV total antibodies, anti-HAV immunoglobulin M (IgM) and anti-HEV IgM by the enzyme-linked immunosorbent assay. PCR for nucleic acid detection of HBV and HCV was also carried out. Those positive for HBV infection were tested for anti-HDV antibodies.

STATISTICAL ANALYSIS USED

Fisher's exact test was used and a P < 0.05 was considered to be statistically significant.

RESULTS

Of the 267 viral hepatitis cases, 62 (23.22%) patients presented as acute hepatic failure. HAV (26.96%) was identified as the most common cause of acute hepatitis followed by HEV (17.97%), HBV (16.10%) and HCV (11.98%). Co-infections with more than one virus were present in 34 cases; HAV-HEV co-infection being the most common. HEV was the most important cause of acute hepatic failure followed by co-infection with HAV and HEV. An indication towards epidemiological shift of HAV infection from children to adults with a rise in HAV prevalence was seen.

CONCLUSIONS

To the best of our knowledge, this is the first report indicating epidemiological shift of HAV in Uttar Pradesh.

Predicting the presence of hepatitis B virus surface antigen in Chinese patients by pathology data mining

Hepatitis B virus (HBV) is a pathogen of worldwide health significance, associated with liver disease. A vaccine is available, yet HBV prevalence remains a concern, particularly in developing countries. Pathology laboratories have a primary role in the diagnosis and monitoring of HBV infection, through hepatitis B surface antigen (HBsAg) immunoassay and associated tests. Analysis of HBsAg immunoassay and associated pathology data from 821 Chinese patients applied 10-fold cross-validation to establish classification decision trees (CDTs), with CDT results used subsequently to develop a logistic regression model. The robustness of logistic regression model was confirmed by the Hosmer-Lemeshow test, Pseudo-R(2) and an area under receiver operating characteristic curve (AUROC) result that showed the logistic regression model was capable of accurately discriminating the HBsAg positive from HBsAg negative patients at 95% accuracy. Overall CDT sensitivity and specificity was 94.7% (± 5.0%) and 89.5% (± 5.7%), respectively, close to the sensitivity and specificity of the immunoassay, providing an alternative to predict HBsAg status. Both the CDT and logistic regression modeling demonstrated the importance of the routine pathology variables alanine aminotransferase (ALT), serum albumin (ALB), and alkaline phosphatase (ALP) to accurately predict HBsAg status in a Chinese patient cohort. The study demonstrates that CDTs and a linked logistic regression model applied to routine pathology data were an effective supplement to HBsAg immunoassay, and a possible replacement method where immunoassays are not requested or not easily available for the laboratory diagnosis of HBV infection.

A Bayesian meta-analysis on prevalence of hepatitis B virus infection among Chinese volunteer blood donors

BACKGROUND

Although transfusion-transmitted infection of hepatitis B virus (HBV) threatens the blood safety of China, the nationwide circumstance of HBV infection among blood donors is still unclear.

OBJECTIVES

To comprehensively estimate the prevalence of HBsAg positive and HBV occult infection (OBI) among Chinese volunteer blood donors through bayesian meta-analysis.

METHODS

We performed an electronic search in Pub-Med, Web of Knowledge, Medline, Wanfang Data and CNKI, complemented by a hand search of relevant reference lists. Two authors independently extracted data from the eligible studies. Then two bayesian random-effect meta-analyses were performed, followed by bayesian meta-regressions.

RESULTS

5957412 and 571227 donors were identified in HBsAg group and OBI group, respectively. The pooled prevalence of HBsAg group and OBI group among donors is 1.085% (95% credible interval [CI] 0.859%~1.398%) and 0.094% (95% CI 0.0578%~0.1655%). For HBsAg group, subgroup analysis shows the more developed area has a lower prevalence than the less developed area; meta-regression indicates there is a significant decreasing trend in HBsAg positive prevalence with sampling year (beta = -0.1202, 95% -0.2081~-0.0312).

CONCLUSION

Blood safety against HBV infection in China is suffering serious threats and the government should take effective measures to improve this situation.

The presence of hepatitis B core antibody is associated with more advanced liver disease in alcoholic patients with cirrhosis

BACKGROUND

Liver disease is more severe in patients with chronic hepatitis B virus (HBV) infections and alcohol-induced liver injury. Whether the same is true for alcoholic patients with cirrhosis who have recovered from previous HBV infections remains to be determined.

OBJECTIVES

To document the extent of liver disease in alcoholic patients with cirrhosis who test negative for hepatitis B surface antigen (HBsAg) and test positive for antibody to hepatitis B core antigen (anti-HBc).

METHODS

Two hundred fifty-four alcoholic patients with cirrhosis were divided into anti-HBc-positive (N = 171) and anti-HBc-negative (N = 83) cohorts. Demographic, clinical, and biochemical features were retrospectively analyzed. Prognostic scores and the prevalence of patients at high risk for short-term mortality were calculated. Logistic regression was used to identify factors associated with an increased risk for short-term mortality.

RESULTS

Jaundice was more common in the anti-HBc-positive cohort (32.2% vs. 18.1%, p = 0.02). This cohort also had higher serum bilirubin (70.9 vs. 50.4 μM/L, p = 0.03), prothrombin times (15.6 vs. 14.4 s, p = 0.01), MELD scores (8.5 vs. 4.6, p = 0.01), i-MELD scores (28.6 vs. 24.7, p = 0.03), MDF scores (14.2 vs. 6.8, p = 0.02) and ABIC scores (7.2 vs. 6.6, p = 0.01). In addition, anti-HBC-positive patients were more often at high risk for short-term mortality (40.4% vs. 26.5%, p = 0.03). Multivariate analysis identified anti-HBc-positive status (OR: 1.84; 95% CI: 1.10-3.36) and alcohol intake ≥150 g/day (OR: 2.01; 95% CI: 1.10-3.66) as independent risk factors for high risk of mortality.

CONCLUSION

The anti-HBc-positive state is associated with more advanced liver disease in alcoholic patients with cirrhosis. A prospective study including HBV-DNA testing and liver biopsies should be considered to validate and further elucidate these findings.

Decreased antigenicity profiles of immune-escaped and drug-resistant hepatitis B surface antigen (HBsAg) double mutants

BACKGROUND

Selective pressure from either the immune response or the use of nucleoside analogs in antiviral therapy could be driving the emergence of HBV mutants. Because of the overlap of the open reading frame (ORF) S for the HBsAg and ORF P for viral polymerase, rtM204I and rtM204V mutations in the polymerase would produce sI195M and sW196S in the HBsAg. The combined effects of immune-escaped mutations (sT118M, sG145K, sG145R) and drug-resistant mutations (rtM204I, rtM204V) on the antigenicity profiles of HBsAg has not been widely explored.

METHODS

To determine the combined effects of immune-escaped and drug-resistant mutants on the antigenicity profiles of HBsAg, recombinant plasmids encoding HBsAg double mutants were constructed using site-directed mutagenesis. The supernatant from each plasmid transfection was analyzed for HBsAg in the western-blotting and five of the most commonly used commercial ELISA kits in China.

RESULTS

Western-blotting assay showed the successful expression of each HBsAg mutant. All five ELISA kits manifested similar avidity, which were demonstrated by the slope of the curves, for the sT118M mutant, and sT118M-rtM204I (sT118M-sI195M) and sT118M-rtM204V (sT118M-sW196S) double mutants, suggesting that drug-resistant YMDD mutants caused negligible losses in the antigenicity of immune-escaped sT118M HBsAg. In contrast, the presence of the rtM204I (sI195M) mutation, but not rtM204V (sW196S) in combination with the sG145K mutation significantly reduced the avidity of sG145K HBsAg. The rtM204I (sI195M) mutation also decreased the antigenicity profiles for sG145R HBsAg.

CONCLUSIONS

Drug-resistant mutations rtM204I (sI195M) and rtM204V (sW196S) caused significant reduction in antigenicity for the immune-escaped HBsAg mutants sG145K and sG145R, which may hamper HBV diagnosis and disease control from HBV blood-transfusion transmissions in China. The development of ELISA kits with a greater sensitivity for drug-resistant and immune-escaped HBsAg warrants further consideration.

Comparative analysis of triplex nucleic acid test assays in United States blood donors

BACKGROUND

This study assessed the clinical sensitivity of three fully automated, human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) triplex nucleic acid test (NAT) assays by individual donation (ID-NAT) and at operational minipool (MP-NAT) sizes used worldwide.

STUDY DESIGN AND METHODS

MPX, Ultrio, and Ultrio Plus were used to test 2222 pedigreed, marker-positive samples with varying viral loads, each from a unique US blood donor. NAT-positive, seronegative yield samples (16 HBV, 156 HCV, and 23 HIV) were tested in replicates of three; undiluted; and in 1:6, 1:8, and 1:16 dilutions (MP6, MP8, and MP16), simulating various MP sizes. Seropositive samples (1276 HBV, 488 HCV, and 263 HIV) were tested by ID-NAT in singlet.

RESULTS

MPX-MP6 and Ultrio Plus-MP16 had equivalent HCV sensitivity. Although Ultrio Plus-MP16 for HIV trended toward lesser sensitivity, this was not corroborated in a large substudy of low-viral-load samples in which Ultrio Plus-MP8/MP16 showed 100% reactivity. MPX-ID and Ultrio Plus-ID HBV clinical sensitivity were identical, but MPX-MP6 was significantly more sensitive than Ultrio Plus-MP16; the differential yield projected to one HBV NAT yield per 4.72 million US donations. Ultrio Plus HBV sensitivity did not increase at MP8 versus MP16. Ultrio Plus versus Ultrio sensitivity was significantly increased in HBV-infected donors with early acute, late acute or chronic, and occult infections. No difference in sensitivity was noted for any virus for MPX-MP6 versus Ultrio Plus-ID.

CONCLUSIONS

Our data support US donation screening with MPX-MP6 or Ultrio Plus-MP16 since the HBV DNA detection of Ultrio Plus was significantly enhanced (vs. Ultrio) without compromising HIV or HCV RNA detection.

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus

BACKGROUND

We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion-transmitted risk at three large Brazilian blood centers.

STUDY DESIGN AND METHODS

Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HCV. HBV and HCV prevalence rates were calculated for all first-time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors.

RESULTS

There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti-HBc reactivity was 289 per 100,000 donations and of anti-HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77-7.03) per 100,000 person-years, and residual risk of HCV window-phase infections was estimated at 5.0 per million units transfused.

CONCLUSION

Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.

Hepatitis B virus infection among first-time blood donors in Italy: prevalence and correlates between serological patterns and occult infection

BACKGROUND

A prospective, 1-year study was performed among Italian first-time, volunteer blood donors, who account for 12% of all donations, in order to assess the frequency and serological patterns of hepatitis B virus infection and the presence of occult infection.

MATERIALS AND METHODS

Consecutive donors (n=31,190) from 21 blood transfusion centres, from age classes not subjected to universal HBV vaccination, were tested for HBsAg and anti-HBc by commercial immunoassays. Other HBV serological markers were searched for and qualitative and quantitative assessments of HBV-DNA were made in HBsAg and/or anti-HBc-positive individuals.

RESULTS

Of the 31,190 donors studied, 100 (0.32%) were positive for both HBsAg and anti-HBc, 2 for HBsAg (0.01%) alone, and 2,593 (8.3%) for anti-HBc. Of these last, 86.7% were also positive for anti-HBs (with or without anti-HBe), 2.9% were positive for anti-HBe without anti-HBs and 10.4% had no other HBV markers (anti-HBc alone). A general north-south increasing gradient of HBV prevalence was observed. Circulating HBV-DNA was found in 96.8% of HBsAg-positive subjects as compared to 0.55% (12/2,186) of anti-HBc-positive/HBsAg-negative subjects, with higher frequencies among anti-HBs-negative than among anti-HBs-positive ones (1.68% vs. 0.37%; p <0.01) and among the 57 cases positive for both anti-HBc and anti-HBe (7%). HBV-DNA levels were significantly higher in HBsAg-positive subjects than in HBsAg-negative ones (median: 456 IU/mL vs. 38 IU/mL).

CONCLUSIONS

The prevalence of HBV infection among Italian first-time blood donors is much lower than in the past. The presence of occult infections in this group was confirmed (frequency: 1 in 2,599), supporting the hypothesis of long-term persistence of HBV infection after clearance of HBsAg. HBsAg and nucleic acid amplification testing for blood screening and vaccination against HBV are crucial in order to further reduce the risk of transfusion-transmitted HBV towards zero.

T-Cell Response to Hepatitis B Core Antigen: Identification of Prior Exposure to and Confirmatory Testing for Screening for Anti-HBc

Background. During routine donor screening in the blood bank, it is not uncommon to find isolated reactivity for anti-HBc in the absence of detectable HBV DNA in a first donation but absence of reactivity to anti-HBc in subsequent donations, suggesting a false-positive result for anti-HBc. Study Design and Methods. The blood donor population was screened between January 2010 and October 2011. We selected 2,126 donations positive only for anti-HBc from a total of 125,068 donations. During the process, OBI donors were identified, and their HBcAg-specific T-cell response was analyzed and compared to donors with chronic (HBsAg positive) and recovered (anti-HBc only) infection. We analyzed correlations between signal levels (Co/s) in the competitive assay for anti-HBc and HBV DNA detection. Results. In the 21-month study period, 21 blood donors with anti-HBc alone were identified as OBI (1 in each 5955 donors). The relevant finding was the observation that anti-HBc only subjects with Co/s ≥ 0.1 did not have either HBcAg-specific T-cells or detectable HBV DNA and OBI subjects presented with Co/s ≤ 0.1 and HBcAg T-cell response. In the subset of 21 OBI subjects, 9 donors remained positive for HBcAg T-cell response after four collections. In all 9 samples, we observed HBV DNA fluctuation. Conclusion. Our data suggest that HBcAg-specific T-cell response could be used to confirm anti-HBc serological status, distinguishing previous exposure to Hepatitis B virus from anti-HBc false-positive results.

Residual risk of transfusion-transmitted hepatitis B virus (HBV) infection caused by blood components derived from donors with occult HBV infection in Japan

BACKGROUND

Nucleic acid amplification testing (NAT) for hepatitis B virus (HBV) during blood screening has helped to prevent transfusion-transmitted HBV infection (TT-HBV) in Japan. Nevertheless, 4 to 13 TT-HBV infections arise annually.

STUDY DESIGN AND METHODS

The Japanese Red Cross (JRC) analyzed repository samples of donated blood for TT-HBV that was suspected through hemovigilance. Blood donations implicated in TT-HBV infections were categorized as either window period (WP) or occult HBV infection (OBI) related. In addition, we analyzed blood from 4742 donors with low antibody to hepatitis B core antigen (anti-HBc) and antibody to hepatitis B surface antigen (anti-HBs) titers using individual-donation NAT (ID-NAT) to investigate the relationship between anti-HBc titer and proportion of viremic donors.

RESULTS

Introduction of a more sensitive NAT method for screening minipools of 20 donations increased the OBI detection rate from 3.9 to 15.2 per million, while also the confirmed OBI transmission rate increased from 0.67 to 1.49 per million. By contrast the WP transmission rate decreased from 0.92 to 0.46 per million. Testing repository samples of donations missed by minipools of 20 donations NAT showed that 75 and 85% of TT-HBV that arose from WP and OBI donations, respectively, would have been interdicted by ID-NAT. The ID-NAT trial revealed that 1.94% of donations with low anti-HBc and anti-HBs titers were viremic and that anti-HBc titers and the frequency of viremia did not correlate.

CONCLUSIONS

The JRC has elected to achieve maximal safety by discarding all units with low anti-HBc and anti-HBs titers that account for 1.3% of the total donations.

A comparison of human immunodeficiency virus, hepatitis C virus, hepatitis B virus, and human T-lymphotropic virus marker rates for directed versus volunteer blood donations to the American Red Cross during 2005 to 2010

BACKGROUND

At most US blood centers, patients may still opt to choose specific donors to give blood for their anticipated transfusion needs. However, there is little evidence of improved safety with directed donation when compared to volunteer donation.

STUDY DESIGN AND METHODS

The percentage of directed donations made to the American Red Cross (ARC) from 1995 to 2010 was determined. Infectious disease marker rates for human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), and human T-lymphotropic virus (HTLV) were calculated for volunteer and directed donations made from 2005 to 2010. Odds ratios (ORs) were calculated to compare marker-positive rates of directed donations to volunteer donations.

RESULTS

The percentage of donations from directed donors declined from 1.6% in 1995 to 0.12% in 2010. From 2005 to 2010, the ARC collected 38,894,782 volunteer and 69,869 directed donations. Rates of HIV, HCV, HBV, and HTLV for volunteer donations were 2.9, 32.2, 12.4, and 2.5 per 100,000 donations, respectively; for directed, the rates were 7.2, 93.0, 40.1, and 18.6 per 100,000. After demographics and first-time or repeat status were adjusted for, corresponding ORs of viral marker positivity in directed versus volunteer donations were not significant for HIV, HBV, or HTLV and significant for HCV (OR, 0.7; 95% confidence interval, 0.50-0.90).

CONCLUSIONS

Directed donations have declined by 92% at the ARC since 1995, but have higher viral marker rates than volunteer donations. The difference can be explained in part by the effects of first-time or repeat status of the donors. Patients considering directed donation should be appropriately counseled about the potential risks.

First WHO International Reference Panel containing hepatitis B virus genotypes A-G for assays of the viral DNA

BACKGROUND

WHO International Standards (IS) are provided for the calibration and validation of diagnostic and screening assays, e.g. for hepatitis B virus (HBV). HBV forms numerous subgenotypes and the current IS for HBV DNA reflects subgenotype A2.

OBJECTIVE

A reference panel with the most prevalent subgenotypes should facilitate evaluation of genotype-specific detection efficiencies.

STUDY DESIGN

215 HBV positive plasma samples collected worldwide were characterized for HBV markers and sequenced. Fifteen subgenotype A1, A2, B2, B4, C2, D1, D3, E, F2 and G samples were selected for the panel. The lyophilized samples were tested in parallel with the IS in an international collaborative study with 16 laboratories using 13 different nucleic acid amplification techniques (NATs).

RESULTS

Eight of 13 NAT had a HBV DNA detection efficiency which was independent of the genotype and consistent with the IS, while with five assays, certain deviations were noted, particularly with genotype F which was under quantitated or even missed by three assays. The panel was accepted by the WHO as the "1st WHO International Reference Panel for HBV Genotypes for HBV NAT-Based Assays".

CONCLUSIONS

The evaluation of HBV DNA assays should include many different genotypes. The WHO Reference Panel is universally available for manufacturers of HBV DNA assays, diagnostic laboratories and control authorities to facilitate standardized validation of HBV genotype specific detection efficiency of both diagnostic (quantitative and qualitative) and screening NAT assays.

Hepatitis B surface antigen variants in voluntary blood donors in Nanjing, China

Background

Hepatitis B virus (HBV) is still one of the serious infectious risks for the blood transfusion safety in China. One plausible reason is the emergence of the variants in the major antigenic alpha determinant within the major hydrophilic region (MHR) of hepatitis B surface antigen (HBsAg), which have been assumed to evade the immune surveillance and pose a challenge to the disease diagnosis. It is well documented that some commercial ELISA kits could detect the wild-type but not the mutant viruses. The high prevalence of HBV in China also impaired the application of nucleic acid testing (NAT) in the improvement of blood security. Molecular epidemiological study of HBsAg variations in China is still limited. This study was designed to identify the prevalence of mutations in the HBsAg in voluntary blood donors in Nanjing, China.

Methods

A total of 20,326 blood units were enrolled in this study, 39 donors were positive for HBV S gene in the nested-PCR. Mutations in the major hydrophilic region (MHR; aa 99-169) were identified by direct sequencing of S region.

Results

Among of 20,326 blood units in the Red Cross Transfusion Center of Nanjing from October 2008 to April 2009, 296 samples (1.46%, 296/20,326) were HBsAg positive in the 2 successive rounds of the ELISA test. In these HBsAg positive units, HBV S gene could be successfully amplified from 39 donors (13.18%, 39/296) in the nested-PCR. Sequence analysis revealed that 32 strains (82.1%, 32/39) belong to genotype B, 7 strains (17.9%, 7/39) to genotype C. Besides well known G145R, widely dispersed variations in the MHR of S region, were observed in 20 samples of all the strains sequenced.

Conclusions

HBV/B and HBV/C are dominant in Nanjing, China. The mutations in the MHR of HBsAg associated with disease diagnosis are common.