Frequency and load of hepatitis B virus DNA in first-time blood donors with antibodies to hepatitis B core antigen

Blood donation screening for hepatitis B virus core antibodies: The importance of confirmatory testing and initial implication for rare blood donor groups

BACKGROUND AND OBJECTIVES

Exclusion of blood donors with hepatitis B virus (HBV) core antibodies (anti-HBc) prevents transfusion-transmitted HBV infection but can lead to significant donor loss. As isolated anti-HBc positivity does not always indicate true past HBV infection, we have investigated the effectiveness of confirmatory anti-HBc testing and the representation of rare blood groups in anti-HBc-positive donors.

MATERIALS AND METHODS

Three hundred ninety-seven HBV surface antigen-negative and anti-HBc initially reactive blood donor samples were tested by five different anti-HBc assays.

RESULTS

Eighty percentage of samples reactive in Architect anti-HBc assay were positive by the Murex assay and anti-HBc neutralization. Eleven out of 397 samples showed discordant results in supplementary testing from the Murex confirmatory test result, and five remained undetermined following extensive serological testing. Thirty-eight percentage of anti-HBc-positive donors identified as minority ethnic groups compared with 11% representation in anti-HBc-negative donors (p < 0.0001); the frequency of the Ro blood group in anti-HBc-positive donors was 18 times higher in non-white ethnic groups.

CONCLUSION

Using two anti-HBc assays effectively enabled the identification of HBV-exposed and potentially infectious donors, their deferral and potential clinical follow-up. However, the exclusion of confirmed anti-HBc-positive donors will still impact the supply of rare blood such as Ro.

Challenge of hepatitis B testing following intravenous immunoglobulin therapy in patients with autoimmune skin diseases

Intravenous immunoglobulin (IVIg) contains pooled immunoglobulins from the plasma of healthy blood donors. All plasma samples are tested for HIV, hepatitis viruses (A, B, and C), and parvovirus B19. As part of this screening step, nucleic acid amplification technology (NAT) is used and allows the presence of specific antibodies targeting viral structures that are commonly used to test for infection status, such as anti-hepatitis B surface antigen (HBs) or anti-hepatitis B virus core (HBc) antibodies. For this reason, manufacturers point to the possibility of false-positive viral serological test results following IVIg treatment due to the passive transfer of antibodies. IVIg therapy is commonly used to manage patients with severe, treatment-refractory autoimmune skin diseases. The aim of this cohort study was to retrospectively quantify newly-discovered positive serological HBV test results after IVIg treatment in patients with autoimmune skin diseases. Between March 2018 and June 2021, 28 patients with autoimmune skin diseases received IVIg therapy, of whom 17 were longitudinally followed-up. None of the patients had evidence of active HBV infection prior to IVIg therapy. All patients (n = 17) had detectable anti-HBs antibodies and 12 patients had anti-HBc antibodies 4 weeks after commencing IVIg treatment. Passive antibody transfer seems the most likely interpretation. Nevertheless, complete serological hepatitis assessment should be performed to exclude a new infection. We recommend hepatitis screening before IVIg therapy to prevent diagnostic confusion which may arise due to passive antibody transfer.

Hepatitis B virus (HBV) serological patterns among the HBsAg negative hospital attendees screened for immunization

The Hepatitis B virus (HBV) is a highly infectious virus and is endemic in Uganda. It is one of the major etiological agents for liver diseases including liver cancer. In this work, we evaluated the prevalence of the HBV serological markers and the associated socio-demographic factors among hepatitis B surface antigen (HBsAg) seronegative persons screened during routine immunization against the virus in eastern Uganda. Data on the socio-demographic characteristics were collected using a structured questionnaire, while that on the serological markers were obtained from serum samples and evaluated by using the 5-panel HBV One Step Hepatitis B Virus Combo Test Device (Fastep^R, HBV-P43M). The following markers were evaluated by the panel: HBsAg, HBsAb, HBcAb, and HBeAb. Data were analyzed using SPSS (version 26), and multinomial logistic regression was used to elicit the adjusted odds ratio. All the analysis were performed at a 95% confidence limit, and a P value ≤ 0.05 was considered significant. The 424 participants included in this study were mainly female (62.3%), married (55.4%) and aged 30 years and above (54.2%). The seropositivity of the HBsAb, HBeAb, HBcAb marker prevalence rates was 48(11.3%), 73(17.2%) and 45(10.6%) respectively. The majority of the participants (327, 77.1%) did not present with any marker. Married paricipants were significantly associated with reduced HBsAb seropositvity rate, whereas young people aged 18–29 years were associated the with increased odds of HBsAb seropositivity (p < 0.05). Male participants were significantly associated with the HBeAb and HBcAb seropositivity (p < 0.05). Similarly, contact with an HBV infected person was significantly associated with HBeAb and HBcAb seropositivity (p < 0.05). Further still, blood transfusion was significantly associated with the increased risk of HBcAb seropositivity (P < 0.05). This study has revealed a prevalence of HBV serological markers among the HBsAg seronegative persons in this community and an increased risk of transmission of the virus in the community. Our findings have key consequences pertaining the interventions that are pertinent in the control and prevention of the spread of the virus among apparently health persons.

A Study of Prevalence of Occult Hepatitis B Virus Infection, Knowledge and Preventive Practices Against Hepatitis B Virus in Barbers Serving the Armed Forces

OBJECTIVE

Hepatitis B virus (HBV) infection is a major health problem in the world. Barbers deal with frequent abrasions/lacerations due to sharp equipment, making them a high-risk group. Determination of HBsAg positive status excludes most reservoirs of transmission in the population. However, Occult Hepatitis B continues to be a source of transmission. The aim of this study was to study the prevalence of occult HBV infection in barbers serving the armed forces clientele and evaluate their knowledge and preventive practices against HBV transmission.

METHODS

Seventy-nine HBsAg negative barbers were included in this study and interviewed for the status of immunisation and preventive practices. Anti-HBc total and HBV DNA levels were measured along with a complete haemogram, LFT, PT INR, ultrasound abdomen and Fibroscan of the liver.

RESULTS

The prevalence of occult Hepatitis B status was 3.79%. Among barbers who were anti-HBc total positive, 100% were found to have replicative HBV DNA status. All barbers (100%) were unaware of the existence and modes of HBV transmission and were never screened for HBV; 98.73% of barbers followed improper disinfection practices and were never immunised.

CONCLUSION

The prevalence of occult HBV infection in barbers, absence of immunisation, unawareness and improper disinfection practices are significantly at risk for transmission to the unaware clients. It is important to educate barbers, establish a universal disinfection procedure and implement a system of compulsory Hepatitis B vaccination before the commencement of their trade work.

A novel piperazine derivative that targets hepatitis B surface antigen effectively inhibits tenofovir resistant hepatitis B virus

Chronic hepatitis B virus (HBV) infection is a global problem. The loss of hepatitis B surface antigen (HBsAg) in serum is a therapeutic end point. Prolonged therapy with nucleoside/nucleotide analogues targeting the HBV-polymerase may lead to resistance and rarely results in the loss of HBsAg. Therefore, inhibitors targeting HBsAg may have potential therapeutic applications. Here, we used computational virtual screening, docking, and molecular dynamics simulations to identify potential small molecule inhibitors against HBsAg. After screening a million molecules from ZINC database, we identified small molecules with potential anti-HBV activity. Subsequently, cytotoxicity profiles and anti-HBV activities of these small molecules were tested using a widely used cell culture model for HBV. We identified a small molecule (ZINC20451377) which binds to HBsAg with high affinity, with a KD of 65.3 nM, as determined by Surface Plasmon Resonance spectroscopy. Notably, the small molecule inhibited HBsAg production and hepatitis B virion secretion (10 μM) at low micromolar concentrations and was also efficacious against a HBV quadruple mutant (CYEI mutant) resistant to tenofovir. We conclude that this small molecule exhibits strong anti-HBV properties and merits further testing.

Detection of hepatitis B virus infection in German blood donors 2008-2015

BACKGROUND AND OBJECTIVES

Assessment of HBV-NAT testing compared to HBsAg and anti-HBc screening in German blood establishments for the period 2008-2015.

MATERIALS AND METHODS

Blood donations screened for HBsAg and anti-HBc along with HBV-NAT were evaluated. Sensitivity of HBsAg and HBV-NAT tests was compared in 30 HBV seroconversion panels and with the viral load of the NAT-only cases. Residual risk for HBV in the WP was modelled.

RESULTS

A total of 45 270 111 donations were evaluated. There were 29 NAT-only cases in the HBsAg-negative HBV-WP, one by ID-NAT and 28 by MP-NAT. MP-NAT, on average, showed higher sensitivity than HBsAg testing: MP-NAT-LoD of 146 IU/ml vs. 362 IU/ml HBV DNA for positive HBsAg detection (range 135-1502 IU/ml), resulting in 3·1 days (range 2·0-4·8 days) earlier HBV detection. Viral loads of the NAT-only cases confirmed the sensitivity of the HBV tests in the seroconversion study. One HBsAg-negative case was due to a new HBsAg mutant combination. There was one HBsAg-reactive only case. In addition, HBV incidence in the HBV-WP included 41 HBsAg-/HBV-NAT-positives and three HBV transmission cases. The residual risk for HBsAg was estimated to be 1:1 619 419-1 268 474 compared to 1:2 793 365-2 134 702 for MP-NAT. Within chronic HBV (HBsAg-/anti-HBc-positive and MP-NAT-negative) 70% were ID-NAT positive at low viral load (median 20 IU/ml). Among anti-HBc-only, supplementary ID-NAT detected 23 occult HBV infections.

CONCLUSIONS

In the HBV-WP, MP-NAT provided a higher sensitivity than HBsAg testing, obtained a considerably higher yield and reduced the risk for HBV transmission. In later HBV stages, anti-HBc screening and HBV-ID-NAT intercepted potentially infectious donations.

Hepatitis B and C infection in patients undergoing biologic and targeted therapies for rheumatic diseases

Hepatitis B and C are common viral infections that affect more than 430 million population worldwide. In patients with rheumatic diseases, the prevalence of inactive/chronic hepatitis B infection ranges from 0.4% to 38% and that of past/resolved infection is much higher (7.3%-69%). The prevalence of hepatitis C infection in rheumatic disorders is less clear but probably lower than that of hepatitis B (1.7%-4%). With the increasing use of biologic and targeted disease-modifying antirheumatic drug therapies, reactivation of past and chronic hepatitis B and C infection is increasingly recognized, with presentation ranging from asymptomatic viremia to serious clinical hepatitis with liver failure. The concomitant use of effective antiviral therapies helps reduce the risk of hepatitis B reactivation and control of active hepatitis C infection. This article summarizes the prevalence and risk factors of hepatitis B and C reactivation in patients with rheumatic diseases undergoing biologic and targeted therapies, as well as the recommendations for screening, monitoring, and treatment of these infections.

Real Time Polymerase Chain Reaction for Hepatitis B Screening in Donor Corneas in the Central Eye Bank of Iran

PURPOSE

The aim of this study was to report the results of the use of real-time polymerase chain reaction (PCR) for the diagnosis of hepatitis B virus (HBV) infection in cornea donors at the Central Eye Bank of Iran.

METHODS

Between 2014 and 2016, all cornea donors that had negative screening serologic results for hepatitis B (HB) surface antigen, HB surface antibody (Ab), hepatitis C virus Ab, human immune deficiency virus Ab, human T-cell leukemia virus Ab, and syphilis, and positive serology for HB core Ab were subjected to real-time PCR with a detection limit of 400 IU/mL to identify HBV DNA. Positive results for HBV DNA were considered occult HBV infections in these donors.

RESULTS

Over the 3-year period, 122 out of 10448 cornea donors had negative screening serologic tests outside of HB core Ab. Of which, 90 cases were subjected to real-time PCR. Occult HBV was detected in 11 cases (12.2%), resulting in the rejection of the corresponding corneas. The remaining 79 cases (87.8%) had negative results for HBV DNA and the corresponding corneas were used for transplantation.

CONCLUSION

Implementation of PCR for the detection of occult HBV in cornea donors is necessary to not only increase the security level of cornea donation but also minimize the rejection rate of donors that have isolated HB core Ab reactivity.

Prevalence and characterization of occult hepatitis B infection among blood donors in central Saudi Arabia

OBJECTIVES

To evaluate the prevalence of occult hepatitis B viral infections (OBIs)  among blood donors considering the clinical and epidemiological importance of identifying OBIs.

METHODS

A cross-sectional study conducted at King Khalid University Hospital, Riyadh, Saudi Arabia between January 2011 and January 2012. Blood donors (n=8501) were screened for Hepatitis B virus surface antigen (HBsAg) and hepatitis B core antibodies (HBcAb). All HBsAg-negative and HBcAb-positive samples were tested further for hepatitis B surface antibodies (HBsAb), hepatitis B virus (HBV)-DNA, and HBV genotyping.  

RESULTS

Of the 8501 serum samples tested, 56 (0.7%) were positive and 8445 (99.3%) were negative for HBsAg. Among the HBsAg-negative samples, 198 (2.3%) were positive for HBcAb and these patients were suspected to have OBIs. Among the HBcAb-positive samples, 119 (60.1%) were positive while 79 (39.9%) were negative for HBsAb. Analysis of HBV-DNA for the suspected OBIs showed that 17 out of 198 samples (8.6%) yielded positive results, and all of them were HBsAb-negative. The viral load was low (less than 20-186 IU/mL) in all OBIs. Hepatitis B virus genotyping showed that 15 out of 17 samples (88.2%) were genotype D, and the other 2 samples (11.8%) were genotype E. 

CONCLUSION

The prevalence of OBIs among blood donors in Riyadh was 0.2%. Therefore, it is recommended that HBV molecular testing should be incorporated with serological assays for screening of blood donors.

Characterisation and follow-up study of occult hepatitis B virus infection in anti-HBc-positive qualified blood donors in southern China

BACKGROUND

Most major Chinese blood centres look for hepatitis B surface antigen (HBsAg) and perform nucleic acid testing to screen blood for hepatitis B virus infection. The search for antibodies to the core of hepatitis B virus (anti-HBc) has not been implemented because it would lead to a high rate of discarded blood units. The aim of this study was to evaluate the prevalence of occult HBV infection among anti-HBc-positive qualified blood donors in southern China.

MATERIALS AND METHODS

We tested anti-HBc-positive blood donations negative for HBsAg and HBV DNA by standard NAT from Shenzhen for the presence of HBV DNA by sensitive nested and quantitative polymerase chain reactions. Anti-HBs titres were quantified. HBV DNA-positive donors were traced and followed-up.

RESULTS

Of the 1,033 qualified donors, 47.4% (95% CI: 44.4 to 50.5%) carried anti-HBc as evidence of exposure to HBV. The rate of anti-HBc positivity increased steadily with age, ranging from 32.6% in the age group <30 years to 69.8% in the age group <50 years (p<0.001). Of the 1,033 donors, 777 (75.2%; 95% CI: 72.4 to 77.8%) carried anti-HBs (>10 IU/L). HBV DNA was detected in 14 donors who were anti-HBc-positive, HBsAg-negative and negative by routine NAT. Seven of those 14 specimens had an anti-HBs titre above 100 mIU/mL. The prevalence of OBI in anti-HBc-positive qualified blood donors was 2.86% (95% CI: 1.57 to 4.75%). Eight of the 14 OBI cases were genotype B and one was genotype C; 7/14 cases were followed-up, one case converted to anti-HBe. HBV DNA became undetectable in all follow-up samples.

DISCUSSION

A small proportion of anti-HBc-positive qualified donors carry HBV DNA after HBsAg and NAT screening. This finding suggests the possibility of HBV transmission from asymptomatic donors, especially in areas of high HBV prevalence. More sensitive NAT rather than anti-HBc testing should be considered to improve blood safety.

Occult Hepatitis B virus infection in previously screened, blood donors in Ile-Ife, Nigeria: implications for blood transfusion and stem cell transplantation

BACKGROUND

Hepatitis B virus (HBV) transmission through blood transfusion is reduced by screening for hepatitis B surface antigen (HBsAg). However this method cannot detect the presence of occult hepatitis B virus infection. This study sought to determine the prevalence of occult hepatitis B virus infection among blood donors in Ile-Ife, Nigeria. For the first time in Nigeria we employed an automated real-time PCR- method to investigate the prevalence of occult HBV in blood donors.

METHODS

Blood donors screened with HBsAg immunochromatographic rapid test kits at the blood transfusion units of two hospitals and found to be negative were recruited into the study. Questionnaires to elicit risk factors for HBV infection were administered and then 10 ml of blood was collected from each donor. Plasma samples obtained from these HBsAg negative blood donors were screened again for HBsAg using an enzyme-linked immunosorbent assay (ELISA) method, and those found negative were screened for the presence of total antibody to the HBV core antigen (anti-HBc) using ELISA method. Those positive to anti-HBc were then tested for HBV DNA, using an automated real-time PCR method.

RESULTS

Five hundred and seven blood donors found HBsAg negative by immunochromatographic rapid test kits at both blood transfusion units, were tested for HBsAg using ELISA and 5 (1 %) were HBsAg positive. The 502 found negative were tested for anti-HBc and 354 (70.5 %) were found positive implying previous exposure to HBV and 19 (5.4 %) of the 354 anti-HBc positive had HBV DNA signifying occult HBV infection. No risk factors were found to be associated with the presence of HBV DNA among those who tested positive.

CONCLUSION

Occult HBV infection exists in blood donors in Ile-Ife, Nigeria and the use of HBsAg alone for screening prospective donors will not eliminate the risk of HBV transmission in blood transfusion or stem cell transplantation.

Prevalence of antibody to Hepatitis B core antigen and Hepatitis B virus DNA in HBsAg negative healthy blood donors

Background

Hepatitis B virus is one of the most important blood born viruses. Although the sensitivity of screening tests has been considerably increased, transmission may still occur due to window period or occult hepatitis B infections (OBIs). This study was aimed at evaluating the prevalence of the anti-HBc and identifying the HBV DNA in HBsAg negative blood donors.

Methods

The Blood samples from 2031 HBsAg-negative blood donors were divided into three aliquots and tested for anti-HBc, anti-HBs and HBV DNA. Serologic screening including anti-HBc and anti-HBs was performed. As a confirmatory test, all positive results for anti-HBc were retested with another kit. Two positive results were considered for anti-HBc positivity. All HBsAg negative selected donations were tested by PCR assay on pooled specimens (five samples per pool), plasma samples found to be HBsAg negative but anti-HBc positive were selected for a single-unit specimen Real-Time assay.

Results

The study population had a mean age of 33.25 ± 10.09 years were mainly composed of males (94.8 %). The seroprevalance rate was 4.9 % for Anti-HBc and 31.9 % for HBsAb. The majority (58.6 %) of Anti-HBc positive cases were regular blood donors with 42–49 years being the largest age group (41.4 %). Neither individual NAT nor pooled NAT test detected any HBV DNA.

Conclusion

However, Screening of anti-HBc Ab is proposed as a method to identify previous contact with HBV, but there is controversy in literature data regarding the cost-benefit of exclusion of positive anti-HBc Ab in blood donors. Our data does not suggest HBc-Ab test as a screening tool in the study setting.

Prevalence of hepatitis B seromarkers and hepatitis C antibodies in blood donors in Basra, Iraq

BACKGROUND

Transfusion-caused hepatitis remains a major problem in Iraq. Therefore, testing for hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc) and antibodies to hepatitis C antigen (anti-HCV) is a very important preventative measure. The objective of this study was to establish the prevalence of hepatitis B and C virus seromarkers among blood donors as a foundation for safe blood transfusion in Iraq.

METHODS

A cross-sectional observational study was conducted in the blood banks in Basra, Iraq from 1 January to 31 December 2013. Blood samples were collected and were tested for HBsAg, anti-HBc and anti-HCV using standard laboratory techniques.

RESULTS

A total of 69 915 blood donors were enrolled for the study. A total of 1625 (2.3%) donors have shown serological evidence for hepatitis B virus infection; of those donors, 125 (0.2%) showed a positive test result for both anti-HBc and HBsAg while 1475 (2.1%) had positive anti-HBc results as the only positive test for HBV infection. There was no significant difference between males and females (p=0.28). The prevalence of anti-HCV was 0.1%.

CONCLUSIONS

This is the first large population study of its kind in Basra, Iraq. The prevalence of hepatitis B and C among blood donors is very low in Basra. Around 2% of blood donors had anti-HBc as the only serological evidence of HBV infection. Inclusion of anti-HBc in routine screening of blood donors in Iraq should be encouraged.

Are current screening protocols for chronic hepatitis B virus infection adequate?

Chronic hepatitis B virus (HBV) infection screening usually includes only HBV surface antigen (HBsAg) testing; HBV core and surface antibody (anti-HBc, anti-HBs) assays, indicating resolved infection and immunity, are not routinely performed. Yet, serum HBV DNA is measurable in approximately 10% of HBsAg-negative/anti-HBc-positive cases, representing occult HBV infection (OBI). Patient blood samples from 2 Veterans Affairs medical center look-back investigations were screened for HBV infection using HBsAg enzyme immunoassays. Supplementary testing included anti-HBc and anti-HBs enzyme immunoassays. For anti-HBc-positive samples, HBV DNA testing was performed. Background OBI prevalence was further estimated at these 2 facilities based on HBV serology testing results from 1999-2012. Finally, a literature review was performed to determine OBI prevalence in the published literature. Of 1887 HBsAg-negative cohort patients, 98 (5.2%) were anti-HBc positive/anti-HBs negative; and 175 (9.3%), anti-HBc positive/anti-HBs positive. Six of 273 were HBV DNA positive, representing 0.3% of the total tested and 2.2% who were anti-HBc positive/anti-HBs negative or anti-HBc positive/anti-HBs positive. Among 32,229 general population veterans at these 2 sites who had any HBV testing, 4/108 (3.7%) were HBV DNA positive, none of whom were part of the cohort. In 129 publications with HBsAg-negative patients, 1817/1,209,426 (0.15%) had OBI. However, excluding blood bank studies with greater than 1000 patients, the OBI rate increased to 1800/17,893 (10%). OBI is not rare and has implications for transmission and disease detection. HBsAg testing alone is insufficient for detecting all chronic HBV infections. These findings may impact blood donation, patient HBV screening, follow-up protocols for patients assumed to have cleared the infection, and initiation of immunosuppression in patients with distant or undetected HBV.

Comparison of Two Test Strategies for Clarification of Reactive Results for Anti-HBc in Blood Donors

OBJECTIVE

Testing for antibodies against hepatitis B core antigen (anti-HBc) was introduced to detect blood donors suffering from occult hepatitis B infection. Confirmation of specification of reactive results in the anti-HBc screening assay is still a challenge for blood donation services.

METHODS

Two different test strategies for confirmation of specification of reactive anti-HBc tests, one performed in our institute and one suggested by the German authority (Paul-Ehrlich-Institut (PEI)), were compared. The first strategy is based on one supplemental anti-HBc test, the other requires two supplemental anti-HBc tests.

RESULTS

389 samples from 242 donors were considered. Both test strategies yielded concordant results in 117 reactive samples termed 'true-positive' or 'specificity confirmed', in 156 reactive samples termed 'false-positive' or 'specificity not confirmed', and in 99 negative samples. In 17 samples obtained from 11 donors, both test strategies gave discrepant results ('false-positive' but 'specificity confirmed'). In 10 of 11 donors, a real HBV infection was very unlikely, one remained unclear. 30 donors considered 'false-positive' became negative in all anti-HBc tests after follow-up testing and thus eligible for donor re-entry.

CONCLUSIONS

The test strategy suggested by the PEI yielded no additional information but induced an overestimation of HBV infections and unnecessary look-back procedures. Many anti-HBc-reactive donors can be regained after follow-up testing.

Hepatitis B virus reactivation associated with antirheumatic therapy: Risk and prophylaxis recommendations

Accompanying the increased use of biological and non-biological antirheumatic drugs, a greater number of cases of hepatitis B virus (HBV) reactivation have been reported in inactive hepatitis B surface antigen (HBsAg) carriers and also in HBsAg-negative patients who have resolved HBV infection. The prevalence of resolved infection varies in rheumatic disease patients, ranging from 7.3% to 66%. Through an electronic search of the PubMed database, we found that among 712 patients with resolved infection in 17 observational cohort studies, 12 experienced HBV reactivation (1.7%) during biological antirheumatic therapy. Reactivation rates were 2.4% for etanercept therapy, 0.6% for adalimumab, 0% for infliximab, 8.6% for tocilizumab, and 3.3% for rituximab. Regarding non-biological antirheumatic drugs, HBV reactivation was observed in 10 out of 327 patients with resolved infection from five cohort studies (3.2%). Most of these patients received steroids concomitantly. Outcomes were favorable in rheumatic disease patients. A number of recommendations have been established, but most of the supporting evidence was derived from the oncology and transplantation fields. Compared with patients in these fields, rheumatic disease patients continue treatment with multiple immunosuppressants for longer periods. Optimal frequency and duration of HBV-DNA monitoring and reliable markers for discontinuation of nucleoside analogues should be clarified for rheumatic disease patients with resolved HBV infection.

Hepatitis B virus can be inhibited by DNA methyltransferase 3a via specific zinc-finger-induced methylation of the X promoter

In this work we explored whether DNA methyltransferase 3a (Dnmt3a) targeted to the HBV X promoter (XP) causes epigenetic suppression of hepatitis B virus (HBV). The C-terminus of Dnmt3a (Dnmt3aC) was fused to a six-zinc-finger peptide specific to XP to form a fused DNA methyltransferase (XPDnmt3aC). The binding and methyl-modifying specificity of XPDnmt3aC were verified with an electrophoretic mobility shift assay and methylation-specific PCR, respectively. XP activity and HBV expression were clearly downregulated in HepG2 cells transfected with plasmid pXPDnmt3aC. The injection of XPDnmt3aC into HBV transgenic (TgHBV) mice also showed significant inhibition, leading to low serum HBV surface protein (HBsAg) levels and a reduced viral load. Thus, XPDnmt3aC specifically silenced HBV via site-selective DNA methylation delivered by zinc-finger peptides. This study establishes the foundation of an epigenetic way of controlling HBV-related diseases.

Enhanced hepatitis B virus (HBV) pre-genomic RNA levels and higher transcription efficiency of defective HBV genomes

Defective hepatitis B virus (dHBV) particles contain genomes corresponding to singly spliced HBV RNA. A limited number of studies show that dHBV is present in all chronically HBV-infected patients. Clinical studies have linked dHBV and dHBV gene products to high virus loads and liver damage. The replication characteristics of dHBV genomes remain poorly understood. We found that the splice donor/acceptor sites critical for the formation of dHBV genomes are conserved across HBV genotypes. We report a novel method to create dHBV constructs from corresponding wild-type (WT) HBV constructs. We assessed the transcriptional characteristics of the dHBV constructs with those of the corresponding WT construct using a cell culture model. Interestingly, dHBV constructs had higher pre-genomic RNA levels, transcription efficiency, HBV e antigen levels and intracellular HBV core antigen levels compared with the corresponding WT HBV constructs. Our findings highlight previously unrecognized fundamental molecular characteristics of dHBV genomes and their potential role in the pathogenesis of HBV infection.

Head-to-head comparison between two screening systems for HBsAG, anti-HBc, anti-HCV and HIV combination immunoassays in an international, multicentre evaluation study

BACKGROUND

Mandatory screening of blood donations for hepatitis B and hepatitis C viruses and human immunodeficiency viruses 1 and 2 requires assays with exceptional sensitivity and specificity. This study reports the results from a direct head-to-head comparison of the Elecsys HBsAG II, Elecsys Anti-HBc, Elecsys Anti-HCV II and Elecsys HIV combi PT immunoassays with the respective ABBOTT PRISM/Architect instrument immunoassays in a multicentre blood bank evaluation study.

STUDY DESIGN AND METHODS

Assay validation was performed in the blood screening laboratories of four blood bank centres in Austria, Germany, Spain and Thailand, where both first-time donor samples (approximately 6000 donors) and repeat donor samples (approximately 14,000 donors) were screened.

RESULTS

Of all screened donor samples, 93 (0.46%) were confirmed to be positive using assays from both manufacturers. The specificity of all immunoassays was >99.5% and was comparable between first-time and multiple-time donors. A direct comparison between the assays from Roche and ABBOTT according to Bland and Altman analysis demonstrated equivalent quality.

CONCLUSIONS

These results suggest that the Elecsys immunoassays for HBV, HCV and HIV infection, with a comparative sensitivity of 100% and a specificity exceeding the common technical specification threshold of >99.5%, meet the stringent performance criteria stipulated for blood donor screening for these infectious agents. Significant differences in the specificity between first-time and repeat donors were not detectable.

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.

Management of the HBV reactivation in isolated HBcAb positive patients affected with Non Hodgkin Lymphoma

BACKGROUND

Occult HBV infection (OBI) is defined by the persistence of HBV in the liver without serum HBsAg and HBVDNA. It represents a life-threatening event during immunosuppressive chemotherapies. An OBI occurs in approximately 18% of HBcAb + patients. International guidelines suggest surveillance for HBV markers in immunosuppressed patients. In Non-Hodgkin Lymphoma (NHL), the prevalence of OBI reactivation remains to be established.

METHODS

In order to determine the prevalence of occult HBV reactivation in a large cohort of patients during chemotherapy for NHL, we analysed 498 NHL patients in a centre of Southern Italy. We evaluated HBV markers, NHL type, treatment type and occurrence of HBV reactivation.

RESULTS

Forty % of patients were treated with monoclonal antibodies and 60.3% without. Ninety-six patients were HBcAb+, HBsAg-. HBV reactivation occurred in ten subjects of this subgroup. All of them were successfully treated with Lamivudine. None of the patients experienced liver-related death. The prevalence of OBI reactivation was of 10.42% in HBcAb + HBsAb- patients. This event occurred in 50% of patients treated with mild immunosuppressive therapies. Each reactivation was treated with Lamivudine.

DISCUSSION

This report suggests that a strict surveillance is important and cost-effective in HBcAb + HBsAg- NHL patients treated with mild immunosuppressive therapies, in order to detect an occult HBV reactivation.

Prevalence of HBc-Ab among HBs-Ag negative healthy blood donors in south of Iran

Background:

The risk of infection with transfusion-transmitted viruses, such as Hepatitis B virus (HBV), has been reduced markedly. However, a zero-risk blood supply remains a popular goal. Anti-hepatitis B core antigen (anti-HBc) is considered to be an effective marker for occult HBV infection, and it has served a significant role in improving blood safety. The purpose of this study was to determine the seroprevalence of anti-HBc antibodies among blood donors.

Methods:

During a period of six months in 2012, 1000 blood donors in Bandar Abbas were investigated for the presence of HBV infection markers. We used ELISA for the detection of HBsAg and chemiluminescence for the detection of HBsAb and anti-HBc antibodies.

Results:

The prevalence of positive anti-HBc among the 1000 donors was 8.3%. Almost 2.3% of the donors were reactive for anti-HBc and negative for HBsAg.

Conclusions:

The study showed that more than 2% of healthy blood donors in Bandar Abbas already have been exposed to HBV, although their HBsAg tests were negative. We suggest screening for anti-HBc to improve the safety of the blood supply.

Prevalence, risk factors, and impact of isolated antibody to hepatitis B core antigen and occult hepatitis B virus infection in HIV-1-infected pregnant women

BACKGROUND

Prevalence and risk factors for isolated antibody to hepatitis B core antigen (anti-HBc) and occult hepatitis B virus (HBV) infection are not well known in human immunodeficiency virus type 1 (HIV-1)-infected pregnant women. It is unclear if women with occult infections are at risk of transmitting HBV to their infants.

METHODS

HIV-1-infected and HBV surface antigen (HBsAg)-negative pregnant women were tested for antibody to HBsAg (anti-HBs) and anti-HBc using enzyme immunoassay. Women with isolated anti-HBc were assessed for occult HBV infection, defined as HBV DNA levels >15 IU/mL, using the Abbott RealTime HBV DNA assay. Infants born to women with isolated anti-HBc and detectable HBV DNA were tested at 4 months of age for HBV DNA. Logistic regression analysis was used to identify factors associated with isolated anti-HBc and occult HBV infection.

RESULTS

Among 1812 HIV-infected pregnant women, 1682 were HBsAg negative. Fourteen percent (95% confidence interval [CI], 12%-15%) of HBsAg-negative women had an isolated anti-HBc that was independently associated with low CD4 count, age >35 years, birth in northern Thailand, and positive anti-hepatitis C virus serology. Occult HBV infection was identified in 24% (95% CI, 18%-30%) of women with isolated anti-HBc, representing 2.6% (95% CI, 1.9%-3.5%) of HIV-1-infected pregnant women, and was inversely associated with HIV RNA levels. None of the women with isolated anti-HBc and occult HBV infection transmitted HBV to their infants.

CONCLUSIONS

HIV-1-infected pregnant women with isolated anti-HBc and occult HBV infection have very low HBV DNA levels and are thus at very low risk to transmit HBV to their infants.

Occult hepatitis B virus infection among Egyptian blood donors

AIM

To identify blood donors with occult hepatitis B virus (HBV) infection (OBI) to promote safe blood donation.

METHODS

Descriptive cross sectional study was conducted on 3167 blood donors negative for hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV Ab) and human immunodeficiency virus Ab. They were subjected to the detection of alanine aminotransferase (ALT) and aspartate transaminase (AST) and screening for anti-HBV core antibodies (total) by two different techniques; [Monoliza antibodies to hepatitis B core (Anti-HBc) Plus-Bio-Rad] and (ARC-HBc total-ABBOT). Positive samples were subjected to quantitative detection of antibodies to hepatitis B surface (anti-HBs) (ETI-AB-AUK-3, Dia Sorin-Italy). Serum anti-HBs titers > 10 IU/L was considered positive. Quantitative HBV DNA by real time polymerase chain reaction (PCR) (QIAGEN-Germany) with 3.8 IU/mL detection limit was estimated for blood units with negative serum anti-HBs and also for 32 whose anti-HBs serum titers were > 1000 IU/L. Also, 265 recipients were included, 34 of whom were followed up for 3-6 mo. Recipients were investigated for ALT and AST, HBV serological markers: HBsAg (ETI-MAK-4, Dia Sorin-Italy), anti-HBc, quantitative detection of anti-HBs and HBV-DNA.

RESULTS

525/3167 (16.6%) of blood units were positive for total anti-HBc, 64% of those were anti-HBs positive. Confirmation by ARCHITECT anti-HBc assay were carried out for 498/525 anti-HBc positive samples, where 451 (90.6%) confirmed positive. Reactivity for anti-HBc was considered confirmed only if two positive results were obtained for each sample, giving an overall prevalence of 451/3167 (14.2%) for total anti-HBc. HBV DNA was quantified by real time PCR in 52/303 (17.2%) of anti-HBc positive blood donors (viral load range: 5 to 3.5 x 10(5) IU/mL) with a median of 200 IU/mL (mean: 1.8 x 10(4) ± 5.1 x 10(4) IU/mL). Anti-HBc was the only marker in 68.6% of donors. Univariate and multivariate logistic analysis for identifying risk factors associated with anti-HBc and HBV-DNA positivity among blood donors showed that age above thirty and marriage were the most significant risk factors for prediction of anti-HBc positivity with AOR 1.8 (1.4-2.4) and 1.4 (1.0-1.9) respectively. Other risk factors as gender, history of blood transfusion, diabetes mellitus, frequent injections, tattooing, previous surgery, hospitalization, Bilharziasis or positive family history of HBV or HCV infections were not found to be associated with positive anti-HBc antibodies. Among anti-HBc positive blood donors, age below thirty was the most significant risk factor for prediction of HBV-DNA positivity with AOR 3.8 (1.8-7.9). According to HBV-DNA concentration, positive samples were divided in two groups; group one with HBV-DNA ≥ 200 IU/mL (n = 27) and group two with HBV-DNA < 200 IU/mL (n = 26). No significant difference was detected between both groups as regards mean age, gender, liver enzymes or HBV markers. Serological profiles of all followed up blood recipients showed that, all were negative for the studied HBV markers. Also, HBV DNA was not detected among studied recipients, none developed post-transfusion hepatitis (PTH) and the clinical outcome was good.

CONCLUSION

OBI is prevalent among blood donors. Nucleic acid amplification/HBV anti core screening should be considered for high risk recipients to eliminate risk of unsafe blood donation.

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.

Trends in prevalence, incidence, and residual risk of major transfusion-transmissible viral infections in United Arab Emirates blood donors: impact of individual-donation nucleic acid testing, 2004 through 2009

BACKGROUND

United Arab Emirates (UAE) has a heterogeneous population consisting of more than 160 nationalities and 85% of the population being non-UAE. In 2007, Dubai Blood Donation Centre (DBDC), the major local supplier of blood in the UAE, introduced six-minipool nucleic acid test (NAT) for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV), which in 2008 upgraded to individual-donation (ID)-NAT. The aim of this study was to analyze the efficacy of the donor screening program in the UAE and evaluate the impact of NAT on the yield and residual risk of transfusion-transmissible viral infections (TTVIs).

STUDY DESIGN AND METHODS

A total of 169,781 blood donations collected at DBDC between 2004 and 2009 were screened for TTVIs. During the period 2008 through 2009, a total of 59,283 donations were tested with both ID-NAT and serologic assays. The incidence, prevalence, and residual risk for each viral agent were estimated and analyzed.

RESULTS

The individual prevalences of HBV, HCV, and HIV per 100,000 donation were 234.4, 110, and 4, respectively. Calculated residual risk per million donations for HBV was decreased from 1.41 in pre-NAT period to 0.92 in post-NAT period. These figures were decreased for HCV and HIV from 1.73 and 0.39 to 0 and 0.32, respectively.

CONCLUSION

Incidence rates and estimated residual risk indicate that the current risk of TTVIs attributable to blood donation is relatively low in the UAE. The study recommends the parallel use of both serology and ID-NAT TTVIs screening in blood donations and suggests the exclusion of antibody to hepatitis B core antigen-positive donations as this can eliminate the potential infectivity of these units with marginal effects on the blood stock in UAE.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Molecular characterization of hepatitis B virus strains circulating in Belgian patients co-infected with HIV and HBV: overt and occult infection

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) have similar transmission routes, implying that patients infected with HIV are at particular risk for HBV infection. Patients who are co-infected with HIV and HBV progress more rapidly to end-stage liver disease and different HBV genotypes may have a distinct impact on disease progression. One hundred ninety-one anti-HBc-positive sera from Belgian patients co-infected with HIV and HBV were collected during 1998-2008. Full-length HBV genomes as well as large S or partial S genes were amplified and their molecular evolutionary history was analyzed. Clinically, 30 (65.8%) patients were categorized as "overt infection" and 16 (34.7%) cases were categorized as "occult infection." Five distinct HBV genotypes comprising A (69.6%), E (19.6%), followed by D, C, and G were detected. HBV genotype A was observed in all clinical groups and in patients with varying ethnical background. HBV genotype E could be detected in African patients who were mostly infected by heterosexual contacts. Several clinically important mutations at the HBs major hydrophilic region were detected in the new isolates but with no significant difference between occult and overt infection. The high prevalence of HBV genotype A in overt and occult cases, and in particular the detection of certain HBV subgenotypes in patients co-infected with HIV and HBV that carry diagnostic escape mutations, may provide useful information for national guidelines for prophylaxis and treatment.

Hepatitis B core antibody testing in Indian blood donors: A double-edged sword!

BACKGROUND

Until lately, anti-HBc antibodies were considered an effective marker for occult Hepatitis B virus (HBV) infection and have served their role in improving blood safety. But, with the development of advanced tests for HBV DNA detection, the role of anti-HBc in this regard stands uncertain.

MATERIALS AND METHODS

Anti-HBc and HBsAg ELISA and ID-NAT tests were run in parallel on donor blood samples between April 1, 2006 and December 31, 2010 at the Department of Transfusion Medicine, Indraprastha Apollo Hospitals, New Delhi. A positive ID-NAT was followed by Discriminatory NAT assay.

RESULTS

A total of 94 247 samples were tested with a total core positivity rate of 10.22%. We identified nearly 9.17% of donors who were reactive for anti-HBc and negative for HBsAg and HBV DNA. These are the donors who are potentially non-infectious and may be returned to the donor pool.

CONCLUSION

Although anti HBc testing has a definite role in improving blood safety, centers that have incorporated NAT testing may not derive any additional benefit by performing anti-HBc testing, especially in resource-limited countries like ours.

Prevention of post-transfusion hepatitis by screening of antibody to hepatitis B core antigen in healthy blood donors

Background

Transfusion-associated hepatitis B viral infection continues to be a major problem in India even after adoption of mandatory screening for HBsAg by ELISA method. The high incidence of TAHBV is reported in patients receiving multiple transfusions.

Objective

To study the seroprevalence of hepatitis B core antibody among healthy voluntary blood donors

Subjects and Methods

The study was conducted in the department of Transfusion Medicine of a tertiary care referral hospital. A total of 12,232 volunteers after passing through the stringent criteria were selected for blood donation. Donor samples were tested for all mandatory transfusion transmissible infections and anti HBc IgM (Monolisa HBc IgM PLUS:BIO-RAD, France). Reactive results were confirmed by repeat testing in duplicate. Donor data was analyzed using SPSS software and Chi-square test was used to calculate the significance of difference between the groups.

Results

A total of 12,232 healthy voluntary blood donors were recruited. Majority (93.4%) were males. Median age of donor population was 26 years (range: 18–60 years). Eighty six (0.7%) were positive for HBsAg, which comes under “low prevalence (<2%) zone” as per WHO. On screening for HBcAg Ig M, 15 (0.1%) were found to be positive and none were HBsAg reactive. There was no significance of difference in the mean age between reactive and non-reactive donors.

Conclusion

Evaluating the usefulness of anti-HBc screening is critical. Anti HBcAg IgM screening may be included in routine screening of donors as it is an indicator of occult HBV during window period. The cost and the unnecessary wastage of the blood units when they are positive for anti HBsAg along with the core antibody need to be studied.

Hepatitis B core IgM antibody (anti-HBcIgM) among hepatitis B surface antigen (HBsAg) negative blood donors in Nigeria

BACKGROUND

Transfusion associated Hepatitis B virus (TAHBV) continues to be a major problem despite mandatory screening for Hepatitis B surface Antigen (HBsAg). Presence of HBsAg is the common method for detecting hepatitis B infection. Unfortunately, this marker is not detected during the window period of the infection. Nigeria being a developing country cannot afford DNA testing of all collected units of blood which serve as the only possibility of achieving zero risk of transfusion associated HBV. Five different serological makers of hepatitis B virus (HBV) infection were therefore assessed to evaluate the reliability of using HBsAg marker alone in diagnosis of HBV infection among blood donors and to detect the serological evidence of the infection at the window period. This will preclude the possibility of transmitting hepatitis B through transfusion of Hepatitis B surface antigen (HBsAg) negative blood in Nigeria.

METHODS

Between July and August 2009, 92 blood donors were enrolled for the study. The prevalence of 5 different markers of Hepatitis B virus infection was detected using Enzyme Linked Immunosorbent Assay (ELISA). Demographic factors were assessed during the study.

RESULTS

HBsAg and its antibody (anti-HBs) was detected in 18 (19.6%) and 14(15.2%) of the 92 blood donors respectively. Anti-HBc IgM was found in 12(13.0%) of the 92 blood donors while Hepatitis B envelope antigen (HBeAg) and its antibody (anti-HBe) were detected in 4(8.9%) and 12(26.7%) respectively from 45 donors sampled. HBeAg is a marker of high infectivity and appears after HBsAg. At least one serological marker was detected in 30(32.6%) of the blood donors. Five (5.4%) of the 92 donors had anti-HBc IgM as the only serological evidence of hepatitis B virus infection.

CONCLUSIONS

The result of this study shows that five donors have anti-HBcIgM as the only serological evidence of HBV infection. Inclusion of anti-HBcIgM in routine screening of blood donors in Nigeria should be encouraged. This is the first study to assess anti-HBcIgM in the country.

The Role of anti-HBc IgM in Screening of Blood Donors

BACKGROUND

Transfusion transmitted hepatitis B has always been a dreaded disease, with incidence of increased transmission through donated blood. The screening test for hepatitis B infection is detection of HBsAg that does not rule out the risk of transmission of hepatitis B as the donor may be in the 'window period'. During this period, detection of the antibody to the hepatitis B core antigen (anti-HBc) IgM type serves as a useful serological marker. The aim of this study was to screen blood donors for anti-HBc type IgM and anti - HBc Ag total for detection and to find their incidence amongst blood donors.

METHODS

2552 voluntary blood donors were screened by the ELISA method for HBsAg and anti - HBc IgM and other mandatory screening markers. 704 of the test blood samples were also screened for anti-HBc total.

RESULT

Of the 2552 donor, 47 (1.84 %) cases were HBsAg positive. A total of 11 (0.43 %) blood units were reactive for HBcAg IgM and of these, 10 (0.39 %) were HBsAg negative and reactive for anti-HBcAg IgM. Of the 704 samples tested for anti - HBcAg total, 112 (15.9%) samples were reactive.

CONCLUSION

Screening of blood for anti-HBc total is practical in the western world as the incidence of HBsAg and anti-HBc is low in these countries and these positive blood units for anti - HBcAg total can be discarded. This may not be practical in India as the incidence of anti- HBcAg total is high in our population. It is recommended that all blood units should be tested for anti - HBc IgM for infectivity status of the blood donors in the window period and to discard blood if positive.

Reducing the risk of hepatitis B virus transfusion-transmitted infection

Before 1970, approximately 6% of multi-transfused recipients acquired a transfusion-transmitted Hepatitis B virus (HBV) infection. The safety improvements since then have been tremendous. From a level of a few infections per 1000 donations, the risk today, depending on the screening algorithm and additional measurements performed, has decreased to around 1:500,000 to 1:1,000,000, an improvement greater than 1000-fold compared to 50 years ago. This enormous gain in safety has been achieved through many factors, including development of increasingly more sensitive Hepatitis B antigen (HBsAg) assays; the adoption in some countries of hepatitis B core antibody (anti-HBc) screening; an improved donor selection procedure; HBV vaccination programs; and finally the introduction of HBV nucleic acid testing (NAT). Because there is a tendency in transfusion medicine to add one safety measure on top of another to approach the ultimate goal of zero risks, costs become increasingly a matter of debate. It is obvious that any new measure in addition to existing methods or measures will have very poor cost effectiveness. Therefore each country needs to perform its own calculation based on the country’s own epidemiology, resources, political and public awareness of the risks, in order to choose the correct and most cost-efficient measures. Ideally, each country would make decisions regarding implementation of additional blood safety measures in the context of both the perceived benefit and the allocation of overall health care resources.

An overview of occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI), alternatively defined as occult hepatitis B (OHB), is a challenging clinical entity. It is recognized by two main characteristics: absence of HBsAg, and low viral replication. The previous two decades have witnessed a remarkable progress in our understanding of OBI and its clinical implications. Appropriate diagnostic techniques must be adopted. Sensitive HBV DNA amplification assay is the gold standard assay for detection of OBI. Viral as well as host factors are implicated in the pathogenesis of OBI. However, published data reporting the infectivity of OBI by transfusion are limited. Several aspects including OBI transmission, infectivity and its relation to the development of chronic liver diseases and hepatocellular carcinoma have to be resolved. The aim of the present review is to highlight recent data on OBI with a focus on its virological diagnosis and clinical outcome.

Prevalence of occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI) is characterized by the persistence of HBV DNA in the liver tissue in individuals negative for the HBV surface antigen. The prevalence of OBI is quite variable depending on the level of endemic disease in different parts of the world, the different assays utilized in the studies, and the different populations studied. Many studies have been carried out on OBI prevalence in different areas of the world and categories of individuals. The studies show that OBI prevalence seems to be higher among subjects at high risk for HBV infection and with liver disease than among individuals at low risk of infection and without liver disease.

Trends in prevalence of hepatitis B virus infection among Albanian blood donors, 1999-2009

BACKGROUND

Hepatitis B virus (HBV) was among the first virus known to be transmitted by blood and blood productions. The objective of this study is to determine the trend of hepatitis B virus in blood donors.

MATERIALS AND METHODS

In this study 79274 blood donors were retrospectively evaluated for HBsAg. The donors were selected using personal questionnaire, physical examination and testing blood before donation. Blood banks records are used as source of information. The blood donors samples were analyzed for the presence of hepatitis B surface antigen (HBsAg) by commercial available kits ELISA method, third generation (from Abbott laboratory, Germany). A sample was considered as HBsAg positive when found twice repeatedly reactive. Reactive samples were not confirmed with addition tests.

RESULTS

In the evaluation data, we found out that from 79274 of the total healthy blood donors, 15983 were voluntary donors, 52876 were family replacement donors and 10424 commercial blood donors. The prevalence of HBsAg in blood donors was 7.9%. It was increased steadily from 5.9% in 1999 to 9.1% in 2006 and decreased in 7.9% in 2009. According to blood donors status the HBsAg prevalence was 10.5% in commercial blood donors, 8.1% in voluntary donors and 8.6% in family replacement donors. The prevalence of anti-HBc in blood donors was 59.1%.

CONCLUSION

The prevalence of HBsAg was lower in voluntary non remunerate blood donors than commercial donors and family replacement blood donors. In FDs the prevalence was higher than VDs but lower than CDs. So, it is important to encourage the voluntary blood donors to become regularly blood donors.

Efficacy of individual nucleic acid amplification testing in reducing the risk of transfusion-transmitted hepatitis B virus infection in Switzerland, a low-endemic region

BACKGROUND

The risk of transfusion-transmitted hepatitis B virus (HBV) in Switzerland by testing blood donors for hepatitis B surface antigen (HBsAg) alone has been historically estimated at 1:160,000 transfusions. The Swiss health authorities decided not to introduce mandatory antibody to hepatitis B core antigen (anti-HBc) testing but to evaluate the investigation of HBV nucleic acid testing (NAT).

STUDY DESIGN AND METHODS

Between June 2007 and February 2009, a total of 306,000 donations were screened routinely for HBsAg and HBV DNA by triplex individual-donation (ID)-NAT (Ultrio assay on Tigris system, Gen-Probe/Novartis Diagnostics). ID-NAT repeatedly reactive donors were further characterized for HBV serologic markers and viral load by quantitative polymerase chain reaction. The relative sensitivity of screening for HBsAg, anti-HBc, and HBV DNA was assessed. The residual HBV transmission risk of NAT with or without anti-HBc and HBsAg was retrospectively estimated in a mathematical model.

RESULTS

From the 306,000 blood donations, 31 were repeatedly Ultrio test reactive and confirmed HBV infected, of which 24 (77%) and 27 (87%) were HBsAg and anti-HBc positive, respectively. Seven HBV-NAT yields were identified (1:44,000), two pre-HBsAg window period (WP) donations (1:153,000) and five occult HBV infections (1:61,000). Introduction of ID-NAT reduced the risk of HBV WP transmission in repeat donors from 1:95,000 to 1:296,000.

CONCLUSIONS

Triplex NAT screening reduced the HBV WP transmission risk approximately threefold. NAT alone was more efficacious than the combined use of HBsAg and anti-HBc. The data from this study led to the decision to introduce sensitive HBV-NAT screening in Switzerland. Our findings may be useful in designing more efficient and cost-effective HBV screening strategies in low-prevalence countries.

Factors associated with isolated anti-hepatitis B core antibody in HIV-positive patients: impact of compromised immunity

In regions that are hyperendemic for chronic hepatitis B virus (HBV) infection, prevalence of and risk factors associated with isolated anti-hepatitis B core antibody (anti-HBc) in HIV-positive patients are less well described. HIV-positive patients who were tested for hepatitis B surface antigen (HBsAg), anti-hepatitis B surface antibody (anti-HBs) and anti-HBc at designated hospitals for HIV care in Taiwan were included for analysis. HBV DNA was detected by real-time polymerase chain reaction in patients with and without isolated anti-HBc. Of 2351 HIV-positive patients, 450 (19.1%) were HBsAg positive, 411 (17.5%) were anti-HBc positive alone and 963 (41.0%) for both anti-HBs and anti-HBc. Compared with patients who were positive for both anti-HBs and anti-HBc, patients with isolated anti-HBc were older, less likely to have anti-hepatitis C virus antibody (anti-HCV), had lower CD4 lymphocyte counts and higher plasma HIV RNA loads. Older age (adjusted odds ratio, 1.029; 95% confidence interval, 1.015-1.043) and CD4 <100 cells/microL (adjusted odds ratio, 1.524; 95% confidence interval, 1.025-2.265) were independently associated with isolated anti-HBc by logistic regression, while presence of anti-HCV and injecting drug use were not. HBV DNA was detectable in 8.3% of 277 patients with isolated anti-HBc and 14.3% of 56 patients with both anti-HBs and anti-HBc (P = 0.160). In a country hyperendemic for HBV infection, HIV-positive patients at older age and with CD4 <100 cells/microL were more likely to have isolated anti-HBc, suggesting that compromised immunity plays a role in the presence of this marker.

Analysis of sample-to-cutoff ratios on chemiluminescent immunoassays used for blood donor screening highlights the need for serologic confirmatory testing

BACKGROUND

High sample-to-cutoff (s/co) ratios on hepatitis C virus antibody (anti-HCV) screening immunoassays (IAs) are indicative of confirmed-positive results and, according to some reports, can be used to determine anti-HCV status without the need for confirmatory testing. The purpose of this study was to determine whether s/co ratios on hepatitis B surface antigen (HBsAg), antibody to human immunodeficiency virus Types 1 and 2 (anti-HIV-1/2), anti-HCV, and antibody to human T-lymphotropic virus Types I and II (anti-HTLV-I/II) chemiluminescent immunoassays (ChLIAs) can be used to discriminate between biologic false-reactive (BFR) and confirmed-positive results.

STUDY DESIGN AND METHODS

In a blood donor population the s/co ratio distributions for BFR and confirmed-positive results were compared for the Abbott PRISM HBsAg, HIV O Plus, HCV, and HTLV-I/II ChLIAs to determine the extent of overlap between the two distributions for each assay.

RESULTS

The s/co ratio distributions for BFR and confirmed results overlapped in the range of 10.00 to 60.00, 1.00 to 6.00, 3.00 to 15.00, and 1.00 to 100.00 for the PRISM HIV O Plus, HCV, HTLV-I/II, and HBsAg assays, respectively.

CONCLUSION

Although high s/co ratios were predictive of confirmed-positive results in all four assays, a number of confirmed-positive samples gave low values while some biologic false-positive samples showed high values. As the s/co ratio distributions for BFR and confirmed-positive results overlapped for all four PRISM assays, this study highlights the importance of serologic confirmatory testing and the need for caution when using screening IA results to assign a final donor status.

Transfusion-transmitted hepatitis B virus infection

Hepatitis B virus (HBV) remains a major risk of transfusion-transmitted infection due to the pre-seroconversion window period (WP), infection with immunovariant viruses, and with occult carriage of HBV infection (OBI). Reduction of HBV residual risk depends upon developing more sensitive HBV surface antigen (HBsAg) tests, adopting anti-HBc screening when appropriate, and implementing HBV nucleic acid testing (NAT), either in minipools or more efficiently in individual samples. HBV NAT combines the ability to significantly reduce the window period and to detect occult HBV carriage substantiating decades of clinical observation that HBsAg-negative/anti-HBc-positive blood could transmit HBV. Clinical observations suggest limited transmission rate of occult HBV compared to WP. Low transmission rate might be related to low viral load observed in OBIs or to the presence of mutants associated with occult carriage. OBIs carrying detectable anti-HBs ( approximately 50%) are essentially not infectious by transfusion. However, recent data suggest that the neutralizing capacity of low anti-HBs may be inefficient when overcome by exposure to high viral load. Anti-HBc blood units without detectable anti-HBs appear moderately infectious except in immunocompromised recipients. Immunodeficient elderly and patients receiving immunosuppressive treatments may be susceptible to infection with lower infectious dose even in the presence of anti-HBs. The immune status of blood recipients should be taken into consideration when investigating "post-transfusion" HBV infection. Pre-transfusion testing and post-transfusion long-term follow-up of recipients, and molecular analysis of the virus infecting both donor and recipient are critical to definitively incriminate transfusion in the transmission of HBV.