Hepatitis: Allain JP

Reesink HW, Allain JP. · No affiliation provided · Vox Sang. · Pubmed #17105601 No free full text.

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Allain JP, Stramer SL, Carneiro-Proietti AB, Martins ML, Lopes da Silva SN, Ribeiro M, Proietti FA, Reesink HW. · Dept. of Haematology, University of Cambridge, Cambridge, UK. · Biologicals. · Pubmed #19231236 No free full text.

Abstract: A spectrum of blood-borne infectious agents is transmitted through transfusion of infected blood donated by apparently healthy and asymptomatic blood donors. The diversity of infectious agents includes hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency viruses (HIV-1/2), human T-cell lymphotropic viruses (HTLV-I/II), Cytomegalovirus (CMV), Parvovirus B19, West Nile Virus (WNV), Dengue virus, trypanosomiasis, malaria, and variant CJD. Several strategies are implemented to reduce the risk of transmitting these infectious agents by donor exclusion for clinical history of risk factors, screening for the serological markers of infections, and nucleic acid testing (NAT) by viral gene amplification for direct and sensitive detection of the known infectious agents. Consequently, transfusions are safer now than ever before and we have learnt how to mitigate risks of emerging infectious diseases such as West Nile, Chikungunya, and Dengue viruses.

Allain JP. · Department of Transfusion Medicine, Department of Hematology, University of Cambridge, UK. · J Clin Virol. · Pubmed #16831687 No free full text.

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Lee HH, Allain JP. · Department of Haematology, University of Cambridge, UK. · Vox Sang. · Pubmed #15209911 No free full text.

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Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK. · Vox Sang. · Pubmed #15023176 No free full text.

Abstract: Hepatitis B virus (HBV) presents a higher residual risk of transmission by transfusion than hepatitis C virus (HCV) or human immunodeficiency virus (HIV). While most infectious blood units are removed by screening for hepatitis B surface antigen (HBsAg), there is clear evidence that transmission by HBsAg-negative components occurs, in part, during the serologically negative window period, but more so during the late stages of infection. Donations negative for HBsAg, but positive for HBV DNA, with or without the presence of HBV antibodies, correspond to 'occult' HBV infection (OBI). The frequency of OBI depends on the relative sensitivity of both HBsAg and HBV DNA assays. It also depends on the prevalence of HBV infection in the population. OBI may follow recovery from infection, displaying antibody to hepatitis B surface antigen (anti-HBs) and persistent low-level viraemia, escape mutants undetected by the HBsAg assays, or healthy carriage with antibodies to hepatitis B e antigen (anti-HBe) and to hepatitis B core antigen (anti-HBc). Over time, in the latter situation, anti-HBe and, later, anti-HBc may become undetectable. The critical question is whether or not OBI is infectious by transfusion. All forms have been shown to be infectious in immunocompromised individuals, such as organ- or bone marrow-transplant recipients. In immunocompetent recipients, there is no evidence that anti-HBs-containing components (even at low titre) are infectious. Anti-HBc only, with HBV DNA, can be associated with infectivity, as can rare cases of HBV DNA without any serological HBV marker. If HBV nucleic acid amplification technology (NAT) is considered, the OBI viral load would usually be < 500 IU/ml, making testing of plasma pools unsuitable unless the sensitivity of NAT significantly increases by genome enrichment or test improvement.

Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge Blood Centre, Long Road, Cambridge CR2 2PT, UK. · Transfus Clin Biol. · Pubmed #14980545 No free full text.

Abstract: The detection of HBV DNA without HBsAg with or without the presence of HBV antibodies outside the acute phase window period defines occult HBV infection. This condition has been described in hepatocellular carcinoma (HCC), chronic hepatitis B, healthy HBV carriage and recovered infection, chronic hepatitis C and individuals without serological markers of HBV. The frequency of the diagnosis depends on the relative sensitivity of both HBsAg and HBV DNA assays. It also depends on the prevalence of HBV infection in the population. Occult HBV in blood donors has a wide range of potential origins within the natural history of the infection. It may originate from recovered infections with anti-HBs and persistent, low-level, viral replication, escape mutants undetected by the HBsAg assays or healthy chronic carriage. The last situation is mostly found with anti-HBc only. Over time, antibody markers may become undetectable leaving HBV DNA as the only marker of the infection. In all cases, the viral load is low, mostly below 10(4) IU/ml, often below 100 IU/ml. At these levels, nucleic acid testing (NAT) in pools is likely to be largely ineffective. Is occult HBV transmissible by transfusion? Carriers of anti-HBs or anti-HBc only were shown infectious in immunosuppressed organ or bone marrow transplant recipients. In immunocompetent recipients, there is no evidence that anti-HBs-containing components are infectious, even in low titre. Donations carrying anti-HBc only and HBV DNA can be infectious and this is a threat where anti-HBc is not screened. Anti-HBc screening identifies most occult HBV infection but not all. HBV NAT needs either extreme sensitivity or to be performed on individual donations to eliminate HBV DNA-containing units.

Allain JP. · Department of Haematology, Division of Transfusion Medicine, East Anglian Blood Center, Long Road, University of Cambridge, CB2 2PT, Cambridge, UK. <> · Transfus Clin Biol. · Pubmed #12668180 No free full text.

Abstract: The viral safety of the blood supply provided by serological tests alone decreased the residual risk of viral transmission to less than 1:250,000 for hepatitis C virus (HCV) and 1:1.3 M for HIV in the EU and the USA in 2000. This was further improved to 1:2-4 M by the introduction of nucleic acid testing (NAT) for HCV and HIV RNA that considerably reduced the risk of window period transmission. However, over the past 20 years, the successive introduction of up to 10 direct or surrogate viral markers enormously complicated the screening process and testing errors have become the main residual risk of viral transmission by transfusion. At over $ 2 M per QALY, the very low cost-effectiveness of NAT and some other tests overburdens limited funds that might be better used for other health care priorities. At the same time, haemovigilance programmes have shown that blood transfused to the wrong patient and a range of immunological consequences of transfusion caused two deaths per million transfusions and little is done to prevent them. There are means of limiting these serious hazards of transfusion that should become the priority in blood safety.

Allain JP, Thomas I, Sauleda S. · Division of Transfusion Medicine, Department of Haematology, East Anglia Blood Centre, Cambridge, UK. · Transfus Med. · Pubmed #12220257 No free full text.

Abstract: The development of new technologies leads to the discovery of new viruses. For each of these new infectious agents, relevance to transfusion, including transmissibility by transfusion, pathogenicity, prevalence in blood donors, persistence and the availability of screening assays needs to be assessed. Since 1995, one virus and a new family of viruses have been identified. GB virus-C/hepatitis G virus (GBV-C/HGV), a flavi virus with some homology with and epidemiological features of HCV, is not related to post-transfusion hepatitis but seems to positively interfere with human immunodeficiency virus replication. Human circoviruses include TT virus (TTV) and SEN-V. Both are highly variable, constituting a large family of distantly related viruses. They appear ubiquitous, infecting humans very early in life and are largely persistent. No clinical symptoms or pathogenicity is associated with TTV, but SEN-V might be associated with some non-A-E post-transfusion hepatitis. Parvovirus B19 has been known for many years, but its transmission to recipients of plasma derivatives despite viral inactivation raised the issue of screening plasma pools by nucleic acid testing. Most fractionators quantify B19 DNA in plasma pools to ensure a viral load of <10(4) IU mL-1.

Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK. · Blood Rev. · Pubmed #11124105 No free full text.

Abstract: The development of new technologies leads to the discovery of new viruses. For each of these new infectious agents relevance to transfusion needs to be assessed. The questions to be answered are transmissibility by transfusion, pathogenicity, prevalence in blood donors, persistence and the availability of screening assays. Since 1995, three new viruses have been identified and extensively studied. GB virus-C/hepatitis G virus (GBV-C/HGV), a relatively rare virus with some homology with and epidemiological features of HCV, was thought to be related to post-transfusion hepatitis but was proven to be unrelated to hepatitis and is still in search of a disease. Human herpes virus-8 (HHV-8) is a major factor in the pathogenesis of Kaposi's sarcoma and other tumours related to immunodeficiency. HHV-8 transmission by organ transplantation, but not by transfusion, has been demonstrated. The TT virus (TTV) is a ubiquitous virus infecting a very high proportion of humans in infancy. No clinical symptoms or pathogenicity is attached to TTV. To date, none of the emerging viruses have been proven relevant to transfusion.

Allain JP. · Division of Transfusion Medicine, University of Cambridge, Cambridge, UK. · Baillieres Best Pract Res Clin Haematol. · Pubmed #11102280 No free full text.

Abstract: The residual risk of transfusion-transmitted viral infection in developed countries is considered minimal or negligible. However, zero risk remains a strong political objective. Genomic screening for HCV, HIV and HBV represents a major advance, eliminating infectious blood donations collected during the pre-seroconversion window period, rare cases of immunosilent infections and, possibly, a large spectrum of viral variants. In Western countries, HCV RNA genomic screening started on pools of 16-400 plasma samples from individual donations. Pooling may produce false-positive and false-negative results. Individual donation testing is more suitable to blood screening but requires multiplexing, automation, and affordable cost. Because donations from individuals who are HBV DNA-negative/serologically positive, or those apparently recovered from HCV infection, may remain infectious, it is unlikely that HBsAg, anti-HCV, and anti-HIV will be discontinued when genomic screening is extended to all three viruses. HIV-1 p24 antigen may prove redundant with HIV RNA screening. Anti-HTLV-I and HTLV-II will remain more effective than genomic testing.

Allain JP. · Department of Haematology, University of Cambridge, UK. · Vox Sang. · Pubmed #10938961 No free full text.

Abstract: BACKGROUND AND OBJECTIVES: The development of new technologies leads to the discovery of new viruses. For each of these new infectious agents relevance to transfusion needs to be assessed. MATERIALS AND METHODS: The questions to be answered are transmissibility by transfusion, pathogenicity, prevalence in blood donors, persistence and the availability of screening assays. RESULTS: Since 1995, four new viruses have been identified and for three of them extensive studies have been carried out. GBV-C/HGV and TTV were both initially thought to be related to post-transfusion hepatitis but neither were proven to be in any way related to hepatitis and are still in search of a disease. HHV-8 is a major factor in the pathogenesis of Kaposi's sarcoma and other tumours related to immunodeficiency. HHV-8 transmission by organ transplantation but not by transfusion has been demonstrated. SEN-V has been claimed as a potential cause of non-A-E hepatitis but no data has been published. CONCLUSION: To date, none of the emerging viruses have been proven relevant to transfusion.

Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK. · Clin Lab Haematol. · Pubmed #10762297 links to  free full text

Abstract: The residual risk of post-transfusion human immunodeficiency virus (HIV) infection is low but slightly higher for hepatitis B virus (HBV) and hepatitis C virus (HCV), the main reason being viraemia during the window period preceding antibody or antigen detection by enzyme immunoassays. Immunosilent-infected individuals and carriers of distant viral variants also play an unquantifiable role. Multiple techniques, e.g. reverse transcription-polymerase chain reaction (RT-PCR), PCR, ligase-chain reaction, nucleic acid sequence-based amplification (NASBA) and transcription-mediated amplification (TMA) have been developed to amplify and detect viral genomes as single or multiplex assays. Equipment providing various degrees of automation has been adapted to these techniques. Applying nucleic acid amplification techniques (NAT) to blood screening, two main approaches have been advocated: plasma pool and single-donation testing. Pool testing presents the advantage of lower cost and readily available equipment although it is prone to false negative and positive reactions. The time required to identify infected donations is incompatible with blood component release, and may lead to product waste. Single-unit testing, although appealing, is not yet fully automated and potentially very costly unless a systematic multiplex approach is taken. Although technically feasible, NAT applied to the blood supply needs to be clinically evaluated and its cost efficiency assessed in the general public health context. However, pool NAT is currently implemented in continental Europe and the USA.

Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, National Blood Service Center, Long Road, Cambridge CB2 2PT, UK. · Vox Sang. · Pubmed #17348876 No free full text.

Abstract: The International Society of Blood Transfusion (ISBT) transfusion-transmitted infections (TTI) working party is proposing to undertake an international collaborative study aimed at understanding occult hepatitis B infection by molecular and immunological characterization, determining infectivity by transfusion and clinical relevance of this newly identified condition. This article provides information to the transfusion community and aims to recruit potential collaborators for the study. Further information can be obtained from the author or the ISBT TTI working group website (http://www.isbt-web.org).

Williamson LM, Llewelyn CA, Fisher NC, Allain JP, Bellamy MC, Baglin TP, Freeman J, Klinck JR, Ala FA, Smith N, Neuberger J, Wreghitt TG. · Division of Transfusion Medicine, University of Cambridge, UK. · Transfusion. · Pubmed #10604250 No free full text.

Abstract: BACKGROUND: Virus inactivation of pooled fresh-frozen plasma (FFP) by the solvent/detergent (SD) method results in a loss of approximately 20 percent of factor VIII. This study aimed to assess the efficacy of SD-treated plasma in correcting the coagulopathy associated with liver disease and liver transplantation. STUDY DESIGN AND METHODS: Forty-nine patients with coagulation deficits due to liver disease, who required FFP for invasive procedures or liver transplantation, were randomly assigned to receive either FFP or SD-treated plasma. Patients were assessed for side effects, correction of coagulopathy over 24 hours, and seroconversion for viral markers 6 to 18 months after treatment. RESULTS: In the liver disease group, equal correction of clotting factors and partial thromboplastin time was seen with FFP and SD-treated plasma, with a similar return to baseline values over 24 hours. There was greater correction of the International Normalised Ratio in patients receiving SD-treated plasma (p = 0.037), but this patient group had higher baseline values than recipients of FFP (p = 0.024). Liver transplant patients also showed equivalent correction of coagulopathy with the same dose of FFP and SD-treated plasma. The use of other blood components during transplantation was identical in the two treatment groups. No seroconversions were seen for HIV or hepatitis B or C virus. One patient who had received FFP seroconverted for human parvovirus B19. Apparent seroconversion for hepatitis A virus seen at 9 to 13 months in four other patients was probably due to detection of passively transferred antibodies, as later testing of these patients gave negative results. Minor side effects were rare in both groups. CONCLUSION: SD-treated plasma is an efficacious source of coagulation factors for patients with liver disease who are undergoing biopsy or transplantation. Assessment of seroconversion for viral markers in recipients of plasma-derived products and plasma components should include consideration of the possibility that passively transferred antibodies were detected.

Allain JP, Belkhiri D, Vermeulen M, Crookes R, Cable R, Amiri A, Reddy R, Bird A, Candotti D. · Department of Haematology, University of Cambridge, Cambridge, UK. · Hepatology. · Pubmed #19434719 No free full text.

Abstract: Since October 2005, all blood units collected in South Africa were screened individually for human immunodeficiency virus (HIV)-1, hepatitis B and C virus (HBV, HCV) genomes uncovering preseroconversion window period (WP) infections for each virus and occult HBV infections (OBIs) defined as persistent HBV DNA without detectable hepatitis B surface antigen (HBsAg). Samples identified as HBsAg-negative/DNA-positive were confirmed by combining real-time quantitative polymerase chain reaction, nested amplification, anti-HBc and anti-HBs. Amplified basic core promoter/precore, pre-S/S, and whole genome were sequenced, analyzed, and compared to 73 HBsAg+ strains. Genotype was determined by phylogenetic analysis. From 109 samples examined, 54 were classified as OBI, 14 as WP, 20 as false-positive, five as other classification, and 16 as undetermined due to lack of serological or follow-up data. OBI donors were predominantly males (67%), median age 31 years, black (54%), with normal alanine aminotransferase levels. Viral load ranged between unquantifiable and 518 IU/mL (median 5 IU/mL). Genotype A1 was more frequent (23 strains) than genotype D (seven strains). Genotype A1 strains were little mutated. In the major hydrophilic region, 56.5% strains were wild type or with few amino acid substitutions. Most important, all 13 full genome sequences presented 1 to 7 mutations known to or assumed to negatively impact viral replication. In particular, 6/13 sequences had a stop codon in the HBx gene translated into deletion of 117 or 19-25 C-terminus amino acids not found in 15 HBeAg+ HBsAg+ strains. One WP sequence with an HBx stop codon suggested infectivity. CONCLUSION: Genotype A1 OBIs are different from genotype A2 and D OBIs in that there is little evidence of immune pressure as a major factor involved in OBI genesis. Limited replication appears mostly related to genetic viral defects.

Meldal BH, Moula NM, Barnes IH, Boukef K, Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge Blood Centre, Long Road, Cambridge CB2 0PT, UK. · J Gen Virol. · Pubmed #19339480 No free full text.

Abstract: Tunisia is a medium-level epidemic country for hepatitis B virus (HBV). This study characterizes, for the first time, full genome HBV strains from Tunisia. Viral load quantification and phylogenetic analyses of full genome or pre-S/S sequences were performed on 196 hepatitis B surface antigen (HBsAg)-positive plasma samples from Tunisian blood donors. The median viral load was 64.65 IU ml(-1) (range<5-7.7x10(8) IU ml(-1)) and 89% of samples had viral loads below 10,000 IU ml(-1). Fifty-nine strains formed a novel subgenotype D7, 41 strains clustered in subgenotype D1, seven strains in subgenotype A2 and one strain in genotype C. The novel subgenotype D7 was defined by maximum Bayesian posterior probability, a genetic divergence from other HBV/D subgenotypes by >4% and a stronger HBV/E signal in the X to core genes than subgenotype D1. In conclusion, HBV/D is dominant in asymptomatic Tunisian HBsAg carriers and a novel subgenotype, D7, was the most common subgenotype found in this population.

Allain JP, Opare-Sem O, Sarkodie F, Rahman R, Owusu-Ofori S. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge Blood Centre, Long Road, Cambridge, UK. · Transfusion. · Pubmed #19170991 No free full text.

Abstract: BACKGROUND: In sub-Saharan Africa, the viral marker burden in blood donor populations ranges between 10 and 30 percent. Deferred donors constitute a rare population of asymptomatic human immunodeficiency virus (HIV)- and hepatitis B virus (HBV)-infected individuals with high likelihood of long survival if cared for. Deferred donor care provides an opportunity for a public health impact on highly pathogenic infections. STUDY DESIGN AND METHODS: Between 2004 and 2007, all candidate donors deferred before donation for reactivity of anti-HIV, hepatitis C virus antibody (anti-HCV), and hepatitis B virus surface antigen (HBsAg) rapid tests were informed and referred to a donor care program consisting of test confirmation, information, counseling, and potential referral for follow-up and therapy. Dedicated trained nurses supervised the program including alanine aminotransferase (ALT) level testing to identify liver disease. RESULTS: In a 4-year period 51,100 donors were screened and 5778, 1578, and 227 candidate donors were deferred for reactivity to HBV, HIV, or HCV serologic markers, respectively. The rates of entry into the donor care program were 48, 14.3, and 22 percent of deferred donors, respectively. A total of 83 of 210 HBsAg-positive donors with elevated ALT levels were referred and 66 received antiviral treatment. A total of 89 of 516 confirmed anti-HIV-positive donors were referred to the hospital acquired immune deficiency syndrome clinic for follow-up. CONCLUSIONS: With little additional expense, the deferred donor care program identified asymptomatic infections with high odds of benefiting from monitoring and therapy. In the local circumstances, this public health-limited but definite impact was permitted by the rapid-test pre-donation screening, and this impact could be increased if more resources were available.

Lin YH, Wang Y, Loua A, Day GJ, Qiu Y, Nadala EC, Allain JP, Lee HH. · Diagnostics for the Real World (Europe) Ltd., Cambridge Science Park, Cambridge, United Kingdom. · J Clin Microbiol. · Pubmed #18701669 links to  free full text

Abstract: A new rapid immunochromatographic assay based on the signal amplification system (SAS) has been developed by Diagnostics for the Real World (Europe) Ltd. for the detection of hepatitis B virus surface antigen (HBsAg) in plasma or serum specimens. The SAS format features enhanced sensitivity as a result of an increased binding valence of the detector molecules. We have now evaluated the performance of the new HBsAg rapid test (DRW-HBsAg) in comparison with a well-established commercial rapid test (Determine HBsAg; previously from Abbott Laboratories; now from Inverness Medical Innovations) and with a CE-marked enzyme immunoassay (EIA) (Hepanostika HBsAg Ultra; BioMérieux) as the gold standard. Testing of serially diluted in-house HBsAg-positive samples, the World Health Organization standard, and sensitivity and reference panels yielded an analytical sensitivity for the DRW test of 0.2 to 0.8 IU/ml across HBsAg serotypes. Evaluation with eight commercially available seroconversion panels showed that the DRW-HBsAg test detected HBsAg an average of 6.1 days (range, 3 to 8 days) earlier than the Determine assay (P = 0.0078). Test sensitivity was also examined with two low-titer HBsAg EIA-positive panels in Beijing, China. Whereas 100% of these samples were detected by the DRW-HBsAg test, only 15.0% (P < 0.0001) and 87.3% (P < 0.0001), respectively, were detected by the Determine HBsAg test. The performance of the DRW-HBsAg test was further evaluated with samples determined to be HBsAg positive or negative by the EIA in Conakry, Guinea, and Beijing, China. No significant difference in sensitivity between the DRW and Determine tests was apparent with the HBsAg EIA-reactive samples from Guinea (96.7% versus 94.4%, respectively) or China (99.46 versus 98.92%, respectively). The specificity of the Determine HBsAg test was slightly higher than that of DRW-HBsAg test (100 versus 99.2%, respectively) with samples from EIA-negative blood donors in China. In conclusion, the new DRW HBsAg rapid test is more sensitive than the Determine HBsAg test and is suitable for diagnostic and blood screening in resource-limited settings.

Chuang WC, Allain JP. · Department of Haematology, Division of Transfusion Medicine, Cambridge Blood Centre, University of Cambridge, Long Road, Cambridge CB2 2PT, UK. · J Gen Virol. · Pubmed #18632960 links to  free full text

Abstract: To date, all studies regarding hepatitis C virus (HCV) F protein have been based on expression in vitro/in vivo of recombinant protein or monoclonal antibodies derived from genotype 1a or 1b sequences, but not from other genotypes. The objective of this study was to prepare a putative genotype 2 recombinant F protein and evaluate its reactivity in plasma from individuals with chronic HCV infection or who had recovered from infection. One genotype 2 strain was selected for F protein (F-2) and core expression in bacterial culture. An ELISA was developed and applied to samples from patients with chronic infection or recovered infection of various genotypes. The anti-F-2 response in 117 samples showed a significantly higher reactivity in chronic than in recovered HCV-infected blood donors (P<0.001), but no difference was found among genotypes. However, the correlation between anti-F and anti-core was more significant in genotypes 1 and 2 than in genotype 3. Anti-F-2 titres were also significantly higher in chronic than in recovered individuals (P<0.0001). Antibody titres to recombinant genotype 2 core protein or to genotype 1 multiple proteins used in commercial anti-HCV assays paralleled the anti-F-2 end-point antibody titre. This study thus demonstrated the antigenicity of genotype 2 HCV F protein, although the exact location of the natural frameshift position remains unknown. The difference in anti-F-2 response between chronic and recovered infection, the cross-reactivity irrespective of genotype and the correlation of antibody response with structural and non-structural antigens suggest that the immune response to F protein is an integral part of the natural HCV infection.

Candotti D, Grabarczyk P, Ghiazza P, Roig R, Casamitjana N, Iudicone P, Schmidt M, Bird A, Crookes R, Brojer E, Miceli M, Amiri A, Li C, Allain JP. · National Health Service Blood and Transplant, Cambridge Blood Centre, Cambridge, UK. · J Hepatol. · Pubmed #18602718 No free full text.

Abstract: BACKGROUND/AIMS: Nucleic acid testing (NAT) for hepatitis B virus (HBV) DNA in blood donations identified occult HBV infection (OBI) as a potential threat to blood safety. METHODS: A collaborative study was undertaken to explore the molecular basis of OBIs prevalent in Europe in relation to clinical and serological data. RESULTS: Ninety-one percent of 77 donor samples of European origin HBV DNA positive but HBV surface antigen (HBsAg) negative were confirmed. Viral load ranged between unquantifiable and 5640 IU/mL (median 25 IU/mL). Fifty-two strains were genotyped (14 HBV(A2) and 38 HBV(D)). Compared to HBsAg+ samples, genotype D was significantly more frequent than genotype A2 in OBIs from Poland or Italy (P<0.04). Amino acid substitutions were concentrated in the immunologically active parts of the Pre-S/S proteins (P<0.0001) affecting both cellular CD8 T-cell epitopes and B-cell neutralizing Major Hydrophilic Region epitopes. Substitutions were more frequent in OBIs than in HBsAg+ strains of both genotype D (P<0.001) and A2 (P<0.01), in OBIs of genotype D than A2 in the 'a' region (P<0.001) but not cellular epitopes, and in anti-HBs+ than anti-HBs- OBIs (P<0.001). CONCLUSIONS: Results support the hypothesis that humoral and cellular immune pressure on the HBV envelope proteins are major mechanisms generating OBI.

Compston LI, Sarkobie F, Li C, Candotti D, Opare-Sem O, Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK. · J Virol Methods. · Pubmed #18479760 No free full text.

Abstract: In common with latent viruses such as herpesviruses, parvovirus B19, HBV and GBV-C are contained successfully by the immune response and persist in the host. When immune control breaks down, reactivation of both latent and persistent viruses occurs. Two multiplex assays were developed (B19, HBV, HHV-8), (EBV, CMV, VZV) for blood screening, and tested on blood donor samples from Ghana to determine baseline prevalence of viraemia in immunocompetent persons. Single-virus real-time quantitative PCR (qPCR) assays were optimised for viral load determination of positive initial screening. The qPCR method utilised was absolute quantification with external standards. Multiplex and single-virus qPCR assays had similar sensitivity, except for the B19 assay in which sensitivity was 100-fold lower. Assays were optimised for reproducibility and repeatability, with R(2) of 0.9 being obtained for most assays. With the exception of B19 and CMV, assays had 100% detection limit ranging between 10(1) and 10(2) copies, IU or arbitrary units under single-virus and multiplex assay conditions. The prevalence of viraemia was 1.6% HBV (0.8% DNA+/HBsAg-, 0.8% DNA+/HBsAg+), 0.8% parvovirus B19, and 3.3% GBV-C viraemia in the plasma fraction. The prevalence of four herpesviruses was 1.0% HHV-8, 0.85% CMV, and 8.3% EBV, and no detectable VZV viraemia.

Wendel S, Levi JE, Biagini S, Candotti D, Allain JP. · Blood Bank, Hospital Sirio Libanês, São Paulo, Brazil. · Transfusion. · Pubmed #18466175 No free full text.

Abstract: BACKGROUND: Transfusion-transmitted hepatitis B virus (HBV) infection in recipients with drug-related immunodeficiency is rarely described in endemic areas. Hepatitis B surface antigen (HBsAg)-negative infectious donor blood can be identified by sensitive nucleic acid testing (NAT). Two immunodeficient patients who received blood components from a single seronegative blood donor subsequently found to contain HBV DNA are described. MATERIALS AND METHODS: Multiple samples from the implicated donor and the two recipients were tested for HBV serologic and molecular markers. HBV genome fragments were amplified, sequenced, and phylogenetically analyzed. RESULTS: The implicated donation had low-level HBV DNA due to the donor being in the window period before the donor's seroconversion. Recipient 1 had been vaccinated to HBV and carried anti-HBs but remained negative for all other HBV markers until she developed acute hepatitis B (viral load 2.7 x 10(8) IU/mL and alanine aminotransferase [ALT] level 1744 IU/L) 13 months after transfusion of red cells. Identical HBV sequences from both donor and recipient provided evidence of transfusion-related infection. Recipient 2, who received platelets from the same donation while receiving major chemotherapy, remained uninfected. CONCLUSIONS: In unusual circumstances, HBV incubation time can be considerably prolonged. Both active and passive neutralizing antibodies to HBV likely delayed, but did not prevent, acute infection when the immune system was impaired. HBV NAT may have interdicted the infectious unit, although the donation viral load could not be quantified and odds of detection calculated.

Levicnik-Stezinar S, Rahne-Potokar U, Candotti D, Lelie N, Allain JP. · Blood Transfusion Center of Slovenia, Ljubljana, Slovenia. · J Hepatol. · Pubmed #18436328 No free full text.

Abstract: BACKGROUND/AIMS: Occult hepatitis B infection (OBI) in blood donations is not considered infectious when anti-HBs is present. METHODS: Four months after transfusion of eight blood components during coronary arterial bypass surgery, a 59-year-old patient developed acute hepatitis B. A second 71-year-old patient transfused with a red cell concentrate (RCC) from one of these donations had early HBV infection 7 months post-transfusion. Samples were tested for HBV serological markers and HBV DNA was quantified and sequenced. RESULTS: One implicated donation contained anti-HBc, anti-HBs (12 IU/L) and 180 IU/ml of HBV DNA. Previous and subsequent samples contained 3-10 times lower viral load and slightly variable anti-HBs. Two previous donations did not cause HBV infection. Recipients of the FFP and RCC from the index donation were both HBV infected and carried genotype D strains with sequences identical to the donor strain. CONCLUSIONS: Despite anti-HBs, an OBI carrier transmitted HBV to two immunocompetent transfusion recipients.

Reesink HW, Engelfriet CP, Henn G, Mayr WR, Delage G, Bernier F, Krusius T, Assal A, Gallian P, Corbi C, Morel P, David B, De Micco P, Murokawa H, Yugi H, Hino S, Tadokoro K, Flesland O, Brojer E, Letowska M, Olim G, Nascimento F, Gonçalves H, Castro L, Morais M, Stezinar SL, Alvarez M, Sauleda S, González R, Niederhauser C, Stolz M, Allain JP, Owusu-Ofori S, Eglin R, Stramer S, Busch M, Strong DM, Epstein J, Biswas R. · Sanquin Consulting Services, Amsterdam, The Netherlands. · Vox Sang. · Pubmed #18205672 No free full text.

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Zahn A, Li C, Danso K, Candotti D, Owusu-Ofori S, Temple J, Allain JP. · Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge, UK. · J Gen Virol. · Pubmed #18198371 links to  free full text

Abstract: Occult hepatitis B virus (HBV) infection (OBI), defined as the presence of HBV DNA without detectable HBV surface antigen (HBsAg), is frequent in west Africa, where genotype E is prevalent. The prevalence of OBI in 804 blood donors and 1368 pregnant women was 1.7 and 1.5%, respectively. Nine of 32 OBI carriers were evaluated with HBV serology, viral load and complete HBV genome sequence of two to five clones. All samples except one were anti-HBV core antigen-positive and three contained antibodies against HBsAg (anti-HBs). All strains were of genotype E and formed quasispecies with 0.20-1.28% intra-sample sequence variation. Few uncommon mutations (absent in 23 genotype E reference sequences) were found across the entire genome. Two mutations in the core region encoded truncated or abnormal capsid protein, potentially affecting viral production, but were probably rescued by non-mutated variants, as found in one clone. No evidence of escape mutants was found in anti-HBs-carrying samples, as the 'a' region was consistently wild type. OBI carriers constitute approximately 10% of all HBV DNA-viraemic adult Ghanaians. OBI carriers appear as a disparate group, with a very low viral load in common, but multiple origins reflecting decades of natural evolution in an area essentially devoid of human intervention.