Post-transfusion Hepatitis Research Articles

A case of acute posttransfusion hepatitis C of which we can estimate the occurrence by nucleic acid amplification test and cure after therapy with interferon

A case of acute posttransfusion hepatitis C of which we can estimate the occurrence by nucleic acid amplification test and cure after therapy with interferon

Infection with hepatitis A and TT viruses and socioeconomic status in Rio de Janeiro, Brazil.

The prevalence of antibodies directed against the enterically transmitted hepatitis A virus (HAV) was measured in 2 groups of people living in Rio de Janeiro, Brazil. Of 1,056 health care workers (HCWs), 778 (73.7%) were anti-HAV positive. A high prevalence of anti-HAV antibodies (85.7%) was also found among 274 voluntary blood donors (BDs). TT virus (TTV) is a DNA virus that has been found in the sera of patients with post-transfusion hepatitis of unknown etiology. Occurrence of virus shedding suggests that the fecal-oral route may be an important mode of TTV transmission, particularly in the developing world. The presence of TTV DNA was analyzed by PCR in the sera of 191 HCWs and 151 BDs. TTV was detected in 65.4% of HCWs and 79.5% of BDs. In both groups, a family income of < US$400 per month and a level of education of < 11 y of schooling were found to be risk factors for HAV infection. Furthermore, a low family income was associated with TTV viremia in the HCW group. However, the presence of TTV DNA was associated with neither low level of education nor anti-HAV positivity.

IgM-class antibodies to TT virus (TTV) in patients with acute TTV infection

TT virus (TTV) is a human circovirus with a single-stranded, circular DNA genome of 3.8 kb. A method was developed to detect IgM antibodies to TTV as a serological marker for the diagnosis of acute TTV infection. IgM antibodies in test sera were captured by a monoclonal antibody against IgM/μ on a solid support followed by binding of IgM with TTV derived from fecal extract of a TTV carrier. The presence of IgM-specific TTV particles was determined by polymerase chain reaction (PCR) using nucleic acids extracted from the solid support. Anti-TTV IgM was detected in sera from two patients with non-A to G post-transfusion hepatitis, who were positive for TTV DNA during weeks 10–21 and 12–17, respectively, following transfusion. The anti-TTV IgM was detectable after alanine transaminase levels were elevated and TTV DNA was detectable in the patients. The duration of the anti-TTV IgM was short-lived compared with anti-TTV IgG. Anti-TTV IgM was not detected in sera from any of 36 healthy individuals, with no detectable anti-TTV IgG or TTV DNA in their serum. These results indicate that anti-TTV IgM antibodies would be a useful marker to detect acute TTV infection.

Genomic and molecular evolutionary analysis of a newly identified infectious agent (SEN virus) and its relationship to the TT virus family.

A new group of transmissible single-stranded (ss) DNA viruses (SENV) distantly related to the large TT virus (TTV) family was recently identified. Eight different SENV isolates have been found, some with an association with posttransfusion hepatitis. A phylogenetic analysis of near-complete open-reading frame 1, including conserved motifs and excluding recombinant regions, was performed. The analysis used TTV-like minivirus as an outgroup, to determine a root of the phylogenetic tree, and compared 8 SENV isolates, 6 prototype TTV isolates, and 7 TTV variants (including SANBAN, TUS01, PMV, and YONBAN). Four distinct clusters separated by a bootstrap value of 100% were observed. YONBAN isolates formed a distinct outer group, representing the earliest recognized phylogenetic divergence (group 1). Prototype TTV formed group 2, PMV formed group 3, and SENV, SANBAN, and TUS01 isolates formed group 4, the most recently evolved group. This taxonomic classification suggests that these circular ssDNA viruses probably evolved from a common ancestor virus.

Haemophilic patients with hepatitis C have higher viral load compared to other well-defined patient groups.

Comparison of hepatitis C viral load between different patient populations has been hampered by the use of different technology in individual studies. We had the impression that haemophilic (HAEM) patients had a higher serum load of hepatitis C virus (HCV) compared to other HCV-infected patients. We therefore studied viral load and genotypes in active illicit drug users (IDU), HAEM patients and patients with post-transfusion hepatitis (PTH). The study comprises 225 HCV-RNA positive patients, 117 IDU, 60 HAEM patients and 48 PTH patients. All patients were anti-HIV negative. HCV-RNA was measured with a quantitative reverse transcription polymerase chain reaction (RT-PCR) method, HCV-genotypes were determined with genotype specific primers in RT-PCR in 221 patients. Four patients could not be genotyped with our assay and were excluded. Overall viral load was higher in genotypes 1 and 2 compared to genotype 3, median values of HCV-RNA were 1,400 x 10(3) geq ml(-1), 2,700 x 10(3) geq ml(-1) and 270 x 10(3) geq ml(-1), respectively. HAEM patients had significantly higher viral load for both genotypes 1 and 3 compared to the IDU and PTH patients. In a multiple linear regression model HCV-RNA viral load was independently associated with HAEM and genotype, but not to age, gender or disease duration. In conclusion, HAEM patients have higher viral load than IDU and PTH patients. The reason for this is unknown, but it may be due to host factors or mode of transmission with multiple inoculations.

Benefits and Complications of Regular Blood Transfusion in Patients with Beta‐Thalassaemia major

Abstract Early and regular blood transfusion therapy in patients with homozygous β‐thalassaemia decreases the complications of severe anaemia and prolongs survival. In the long term, however, the beneficial effects of transfusions are limited by the organ damage resulting from iron overload, a consequence of the body's limited capacity to excrete iron, and by the complications of infection with blood‐borne agents. Transfusion regimens for β‐thalassaemia have changed substantially during the past four decades. In current protocols, pre‐transfusion haemoglobin concentration should not exceed 95 g/l. This allows adequate control of anaemia, with a relatively low rate of iron accumulation. Although iron chelation therapy has successfully improved survival free from cardiac disease, thalassaemic patients continuously present new clinical challenges. In fact, the vast majority of them suffer from post‐transfusion chronic hepatitis C, which is expected to significantly contribute to morbidity in the forthcoming years. Furthermore, recent studies demonstrated that thalassaemics are at high risk of acquiring several blood‐borne viruses. The potential role of these multiple infections in inducing clinical disease is still uncertain, and needs to be thoroughly clarified in future surveys.

Hepatitis C lookback

Hepatitis C was responsible for the majority of cases of posttransfusion hepatitis before the introduction of a specific screening test for blood donors. Infected recipients may remain asymptomatic for many years, but cirrhosis and hepatocellular carcinoma may develop decades after infection. Lookback, or the identification of recipients of potentially contaminated blood, is now being conducted in many countries, including Holland, Denmark, the United Kingdom, Canada, New Zealand, and the United States. In targeted lookback, recipients of blood from donors subsequently found to be positive for hepatitis C are notified and advised to undergo testing. In general lookback, all patients who received blood before being tested for hepatitis C are advised to undergo testing. Difficulties with both forms of lookback illustrate the importance of vein-to-vein tracking of blood products, including the potential utility of a centralized registry of blood product recipients.

A model of the health and economic impact of posttransfusion hepatitis C: application to cost-effectiveness analysis of further expansion of HCV screening protocols

Cost-effectiveness analyses are needed to decide the value of further expansion of the screening protocols for HCV in blood donors. However, such analyses are hampered by imperfect knowledge of the health and economic repercussions of posttransfusion hepatitis C (PTHC). A Monte Carlo simulation of a Markov model representing the outcomes of patients transfused with HCV-infective blood was used to estimate the health and economic impact of PTHC and to calculate the cost-effectiveness ratio of various HCV screening methods. Median survival for hypothetical patients with PTHC and for controls without hepatitis was 11.25 and 11.75 years, respectively. Overall, 12.3 percent of patients receiving HCV-infective blood will develop chronic hepatitis, 9.3 percent will progress to liver failure, and 9. 25 percent will eventually die of liver disease after a median time of 20.75 years (range, 6-70). Ninety-one percent of the infected blood recipients had no reduction in life expectancy due to PTHC, and the average loss per patient was 0.754 years. The present value of the lifetime health costs incurred by patients with PTHC is $6330 per case. HCV antibody testing increases the patients' life expectancy by 20.4 hours per blood collection tested, and it results in net savings by decreasing the number of patients that will require treatment for liver disease in the future. Adding HCV NAT increases the patients' life expectancy by 0.08 hours per blood collection tested, at a cost-effectiveness ratio of $1,829,611 per QALY gained. PTHC has low health benefits because of the advanced age of many blood recipients. Testing donors for HCV antibodies results in net savings for the health care system, despite low health benefits. Adding HCV NAT would produce little additional gain at a very high cost.

Full-length GB virus C (Hepatitis G virus) RNA transcripts are infectious in primary CD4-positive T cells.

GB virus C (GBV-C or hepatitis G virus) is a recently described flavivirus which frequently leads to chronic viremia in humans. Although GBV-C is associated with acute posttransfusion hepatitis, it is not clear if the virus is pathogenic for humans. We constructed a full-length cDNA from the plasma of a person with chronic GBV-C viremia. Peripheral blood mononuclear cells (PBMCs) transfected with full-length RNA transcripts from this GBV-C clone resulted in viral replication. This was demonstrated by serial passage of virus from cell culture supernatants, detection of increasing concentrations of positive- and negative-sense GBV-C RNA over time, and the detection of the GBV-C E2 antigen by confocal microscopy. In addition, two types of GBV-C particles were identified in cell lysates; these particles had buoyant densities of 1.06 and 1.12 to 1.17 g/ml in sucrose gradients. PBMCs sorted for expression of CD4 contained 100-fold-more GBV-C RNA than CD4-negative cells. Taken together, these data demonstrate that RNA transcripts from GBV-C full-length cDNA are infectious in primary CD4-positive T cells. In contrast, RNA transcripts from an infectious hepatitis C virus clone did not replicate in the same cell culture system. Infectious RNA transcripts from GBV-C cDNA should prove useful for studying viral replication and may allow identification of differences between GBV-C and hepatitis C virus cultivation in vitro.

Retrospective Analysis of Blood Transfusion Recipients: Evidence for Post–Transfusion Hepatitis E

Background and Objectives: Of 200 volunteer blood donors we had screened earlier for hepatitis E virus (HEV) RNA, using reverse–transcription polymerase chain reaction, 3 were positive, raising the possibility of transfusion–associated hepatitis E in areas endemic for this virus. This retrospective study was to reassess the extent of post–transfusion hepatitis E among transfusion recipients, investigated in 1982. Materials and Methods: We re–evaluated 56 recipients followed biweekly for 3 months after transfusion. The controls were 51 normal, healthy persons who gave blood at a 2–month interval, as well as 412 blood donors from whom blood was taken once in 1982. Results: Of the 56 transfusion recipients, 19 were positive for IgG antibodies against HEV (anti–HEV) in the pretransfusion sample. Two of the 37 IgG anti–HEV–negative recipients seroconverted to IgM and IgG anti–HEV 5 and 4 weeks after transfusion, 1 with raised serum alanine aminotransferase levels. None showed symptoms of hepatitis. Attempts to detect HEV RNA in transfused blood, from aliquot units stored at –20°C for over 17 years, were not successful. Of the controls, 17 out of 51 were IgG anti–HEV positive in the initial sample itself. None of the 34 IgG anti–HEV–negative controls seroconverted during the 2–month follow–up. Of the blood donors, 154 out of 412 were IgG anti–HEV positive. None of the 412 donors had circulating IgM anti–HEV antibodies. A significantly higher (p<0.03) proportion of susceptible transfusion recipients were IgM anti–HEV positive as compared with susceptible blood donors. Conclusion: The results suggest that, in countries where HEV is endemic, the transmission of hepatitis E may be associated with blood transfusion.

Detection of hepatitis B virus DNA in blood units with anti-HBc as the only positive serological marker.

Serum samples from 10,629 blood donors were screened for hepatitis B virus (HBV) serological markers (HBsAg, anti-HBs, anti-HBc, anti-HBc IgM), anti-HCV, anti-HIV1/2 and ALT. Seventy five (0.7%) blood donors were found HBsAg-positive, 1,543 (14.5%) were carrying both anti-HBc and anti-HBs. whereas 507 (4.8%) samples were positive only for anti-HBc. Among the group of 507 anti-HBc positive samples, 303 were obtained from regular volunteer blood donors who were studied in two separate time intervals of at least 6 months' duration, and 204 were from first-time blood donors. The possibility of post-transfusion hepatitis B after donation of these 507 blood units was studied by determining the presence of HBV DNA as a marker of viral replication and infectivity. HBV DNA was detected by two methods (i) a chemiluminescent molecular hybridization assay, (ii) polymerase chain reaction (PCR) followed by DNA enzyme immunoassay (DEIA). Six out of 507 samples exhibited HBV DNA results in the gray zone of the hybridization assay, but were confirmed as negative by PCR DEIA. The other 501 samples were HBV DNA-negative by both methods, although 36 of them had increased ALT levels. No cases of post-transfusion hepatitis B were reported during the year in which these 501 blood units were provided. These results show that blood units which were positive only for anti-HBc, with normal ALT and were HBV DNA-negative may be considered not infectious for hepatitis B. Gray zone results of HBV DNA using hybridization quantitative assay must be confirmed as positive or negative by a more sensitive method such as PCR. Blood units which are anti-HBc-positive, with increased ALT levels and are HBV DNA-negative, which appear to not be related to HBV replication and infectivity, may be not safe for donation because of the potential existence of other as yet unknown, hepatotropic viruses.

Impact of TT virus infection in acute and chronic, viral- and non viral-related liver diseases

Background/Aims: The prevalence and pathogenicity of TT virus, recently identified in patients with non A-non G post-transfusional hepatitis, are questioned. Methods: We investigated the impact of this new viral infection in a large series of patients with non A-non G, cryptogenic, non-viral and viral-related, acute and chronic liver diseases ( n=577) and blood donors ( n=300). TTV DNA was detected in serum by heminested polymerase chain reaction. Phylogenetic analysis was performed in 13 isolates. Results: TTV DNA was detected in 6/25 and 15/127 patients with cryptogenic non A-non G acute and chronic liver disease, respectively. TTV DNA positive subjects with post-transfusional acute hepatitis scored negative before transfusion. TTV prevalence was increased in patients with cryptogenic non A-non G acute and chronic liver disease compared to blood donors (6/300; p<0;0.001) and non-viral-related chronic liver diseases (6/137; p<0;0.05). TTV/HBV coinfection was frequently identified (35/147), but this was not the case for HCV-infected subjects (4/77). Transaminase activity or liver histological score was not significantly increased among TTV positive, HBV infected or non A-non G patients. The HBV infection and Mediterranean origin were the risk factors associated with TTV infection. The majority of analysed sequences clustered in genotype 1 (8=1b; 3=1a). Two isolates showed homology to genotype 2. Conclusions: These results support the view that TTV is a widely spread infectious agent with a weak pathogenicity. It raises the possibility, however, that TTV might be implicated in a few cases of acute and chronic non A-non G hepatitis. TTV-DNA-analysed sequences are related to genotypes 1 and 2 described in Europe.

Optimal blood donation screening annotation.

Optimal blood donation screening annotation.

Molecular analysis of HCV type 1 to 5 envelope gene: application to investigations of posttransfusion transmission of HCV.

Until 1990, HCV infection was common in transfused patients, resulting in more than 200,000 cases of posttransfusion hepatitis C in France alone. A molecular method that permits the investigation of posttransfusion hepatitis C infections is presented. Viral sequences in the envelope region of HCV were obtained for 12 pairs of blood recipients and their respective blood donors. The HCV strains studied belonged to types 1 (subtypes 1a and 1b), 2, 3, 4, and 5. Genetic distances and mutation rates were determined, and sequences were submitted to phylogenetic analysis along with sequences retrieved from nucleotide databases. Pairwise distances in the donor-recipient pairs were found to be less than 0.05 mutation per site, which corresponds to a mutation rate ranging from 0.6 x 10(-3) to 2.1 x 10(-3) per site per year. Sequences obtained from the 12 donor-recipient pairs clustered in 12 monophyletic nests. The genetic analysis of the envelope region of HCV can be used for the forensic evaluation of virus transmission. It permits the refutation of a link between blood transfusion and HCV transmission, rather than proof of the existence of such a link.

PCR testing for HCV in anti-HCV negative blood donors involved in the so called HCV +ve post-transfusion hepatitis

Although it is infrequent, post-transfusion HCV infection may occur if the donors blood is collected in the window period between exposure and anti-HCV detectability by ELISA testing. Study design: In these last years, despite of routine application of anti-HCV testing, our blood transfusion center has been involved in 53 cases of alleged post-transfusion HCV hepatitis and look-back programs were set up with the goal of finding out the donors possibly involved in viral transmission. Most of these patients were hematological cases with multiple transfusions given because of aplastic anemia (3 cases), leukemia with or without bone marrow transplantation (5/4 cases) but necessitating long-term platelet support, leukemia and solid cancer patients undergoing autologous PBSC transplantation (3/4 cases) and TTP (2 cases). Only 32 patients were of the simple medical or surgical type, 9 transfused because of cardiac or vascular surgery, 8 because of spine surgery, 5 for different diseases and 5 for different types of cancer surgery. Donor’s infectivity was determined by ELISA anti-HCV testing, by recombinant immunoblotting assay, and by nucleic acid testing. Results and conclusion: No donors out of 267 traced of a total of 359 involved was found with anti-HCV seroconversion, or positive on PCR testing. This suggests that the responsibility for HCV transmission can only hypothetically be related to blood or blood components and that other transmission routes should be found out.

TTV - a virus searching for a disease.

TTV is a new virus which was identified in the serum of a patient with non-A-G post-transfusion hepatitis in Japan. The original workers aimed to account for the small number of post transfusion hepatitis cases found in their clinical practice. Subsequent work has attempted to determine the properties and unravel the natural history of the new agent. The original study applied representational difference analysis to detect foreign DNA sequences which were present only during the acute phase of illness. Subsequent studies have used PCR to study the agent in serum liver and faeces. This review summarises the published data from clinical and epidemiological studies in different countries. The inclusion of the virus in the parvovirus family seems premature because its size is unknown, its reported density is too light and its sequence lacks the characteristic long terminal repeats. The agent can be found in 1-40% of health blood donors in different countries and also in faeces. TTV is ubiquitous but its taxonomic identity and disease load remain to be determined.

Incidence and clinical presentation of posttransfusion TT virus infection in prospectively followed transfusion recipients: emphasis on its relevance to hepatitis.

A novel transfusion-transmissible human DNA virus, TT virus (TTV), has been discovered recently. An attempt was made to determine the incidence and clinical outcome of TTV infection in recipients of blood transfusion. Serial serum samples collected as part of a prospective study of posttransfusion hepatitis were examined for TTV DNA by a nested PCR assay. Among 150 adults undergoing cardiac surgery, posttransfusion specimens from 59 individuals were positive for TTV DNA. Pretransfusion sera were found to be positive in 13 of these individuals. Therefore, 46 (33.6%) of the 137 previously uninfected patients developed new TTV viremia after transfusion. Among the 46 patients, 3 were coinfected with HCV, 5 were coinfected with HGV, and 38 were infected with TTV alone. No apparent symptoms or signs were noted in the 38 patients infected by TTV alone or the 5 infected with HGV plus TTV. The average peak serum ALT activity was 31 IU per L, with persistently normal levels in 34 of the 38 patients with TTV infection alone. In 8 other patients who subsequently developed well-documented non-A-G hepatitis, 3 were positive for TTV (3/8 vs. 46/137, p = 0.8). In 12 patients followed for more than 1 year, TTV viremia persisted in every case. In this population, TTV is transmitted by transfusion to approximately 30 percent of patients who undergo cardiac surgery. Most of the infections appear to become persistent. Despite the high prevalence rate, TTV does not appear to cause hepatitis on its own.

Public health challenges in hepatitis C virus infection.

The discovery a decade ago of the hepatitis C virus (HCV) led to control of post-transfusion hepatitis in many countries, but raised a number of further questions about the transmission and epidemiological distribution of the newly discovered virus. In some countries, the diagnosis of HCV infection has been designated as a notifiable condition, with doctors (or laboratories, or both) required to send case reports to public health authorities. Such case reports of HCV diagnosis are inevitably biased towards people with symptomatic presentations or a known history of exposure, or those who undergo screening for other purposes, such as blood transfusion. Another approach has been the use of serological prevalence surveys either making use of blood that had been taken or tested for other purposes or recruiting specific population groups for the explicit purpose of measuring HCV prevalence. A limited number of surveys have either attempted to obtain true random samples of geographically defined populations, or recruited subjects, such as pregnant women, who may be considered to be broadly representative of the wider population. Injecting drug use is clearly the main mode of HCV transmission in countries that have established comprehensive blood screening, and it remains a major public health challenge. Although mother-to-child transmission is known to occur with a frequency of about 7% there is no proven means of prevention and very little is known about the long-term consequences of maternally transmitted infection. The conclusion from a number of somewhat conflicting studies is probably that HCV infection should not be viewed as a sexually transmissible infection from the perspective of population health strategies. However, people with HCV infection and their sexual partners should minimize the extent of blood contact that may occur through sexual activity.

Indirect evidence of TTV replication in bone marrow cells, but not in hepatocytes, of a subacute hepatitis/aplastic anemia patient

The presence of a new DNA virus (TTV) has been reported in sera from patients with posttransfusion hepatitis of unknown etiology. The precise replication site of TTV, however, has not been established. In this study, the presence of TTV in liver autopsy material, and in bone marrow biopsy and autopsy samples taken from a subacute hepatitis/aplastic anemia patient was determined by PCR and Southern blot analyses. Liver cells were found to contain only TTV DNA and not mRNA. Bone marrow material, especially that taken at biopsy, contained high levels of TTV DNA. It is suggested that the TTV replication site was in the bone marrow rather than in the liver, and that TTV infection was the cause of this patient's aplastic anemia. The precise etiological association of TTV with hepatitis remains to be established. J. Med. Virol. 61:165–170, 2000. © 2000 Wiley-Liss, Inc.

Prevalence and risk factor analysis of TTV infection in prostitutes.

TTV, a DNA virus, has been isolated from patients with non-A to non-E post-transfusion hepatitis. In the past it was assumed that TTV was transmitted parenterally. It is unclear whether sexual contact leads to transmission of this virus. In this study, two sets of TTV-specific polymerase chain reaction primers were used to detect serum TTV DNA in 140 prostitutes and 136 controls. The prevalence of TTV DNA in prostitutes was significantly higher than in the control group (46/140 [32.9%] vs. 29/136 [21.3%]; P = 0.043). There was no significant difference in the prevalence of positive antibody to hepatitis A virus (anti-HAV) in either group (87.8% for prostitutes, 85.3% for controls). No particular risk factor was significantly associated with positive TTV DNA in prostitutes. In summary, TTV is highly prevalent in prostitutes. Transmission of TTV via sexual contact is not as efficient as transmission of hepatitis C and D viruses and GB virus-C hepatitis G virus. The high prevalence of TTV in controls indicates that there are diverse routes of transmission of this virus.