Use of bovine viral diarrhoea virus as an internal control for amplification of hepatitis C virus.

Background And Objectives: Screening for hepatitis C virus (HCV) by polymerase chain reaction (PCR) will be mandatory for screening blood and plasma donors in Europe and elsewhere. This study describes an internally controlled, highly sensitive PCR method designed for screening blood donations in pools.

Material And Methods: RNA extracted from bovine viral diarrhoea virus (BVDV) was used as an internal control to monitor the efficiency of extraction, reverse transcription and amplification steps in HCV PCR.

Transmission rates of hepatitis C virus by different batches of a contaminated anti-D immunoglobulin preparation.

Background And Objectives: The aim of this study was to determine the hepatitis C virus (HCV) infection rate of recipients of different batches of anti-D immunoglobulin associated with an outbreak of HCV infection which occurred in 1977 and its relationship to the polymerase chain reaction (PCR) status of the implicated batches. This study was undertaken to determine the predictive value of HCV genome detection and quantification for subsequent infection in recipients of an HCV-contaminated anti-D immunoglobulin product for intravenous use.

Materials And Methods: Sera from recipients of anti-D were tested by HCV enzyme immunoassay and if found positive were subsequently tested by recombinant immunoblot assay and HCV PCR in a national HCV anti-D screening programme set up in 1994.

Genetic heterogeneity of HIV type 1 subtypes in Kimpese, rural Democratic Republic of Congo.

A relatively low and stable seroprevalence of HIV-1 was previously reported among pregnant women attending for antenatal care between 1988 and 1993 in Kimpese, a rural town in the Democratic Republic of Congo (DRC, formerly Zaire). To characterize the HIV-1 subtypes circulating in this area, we have examined a 330-bp fragment of the p17 region of the gag gene of HIV-1 strains obtained from 70 patients (55 mothers, 15 children), of whom 61 were epidemiologically unlinked. Phylogenetic analyses revealed the existence of at least seven HIV-1 subtypes within the Kimpese region.

Spinal cord pathology and viral burden in homosexuals and drug users with AIDS.

Unless treated with effective antiretroviral therapy many AIDS patients develop a characteristic vacuolar myelopathy of the spinal cord associated with moderate clinical disability. Opinion is divided as to whether vacuolar myelopathy is causally linked to HIV myelitis. To investigate this further, spinal cord pathology was assessed in 41 drug users, 33 homosexual men and 16 other patients, all with AIDS.

Treatment with interferon-alpha2a alone or interferon-alpha2a plus ribavirin in patients with chronic hepatitis C previously treated with interferon-alpha2a. CONSTRUCT Group.

Background: Preliminary results from combination therapy with interferon-alpha and ribavirin (IFN/Rib) in patients with chronic hepatitis C have been promising, with up to 50% sustained hepatitis C virus (HCV) RNA response. The aim of this study was to investigate whether a sustained HCV RNA response could be obtained with combination therapy in patients who were non-responders or relapsers after IFN treatment.

Methods: In a multicenter study we randomized 53 HCV RNA-positive patients into 2 treatment groups.

Early acquisition of TT virus (TTV) in an area endemic for TTV infection.

TT virus (TTV) is widely distributed, with high frequencies of viremia in South America, Central Africa, and Papua New Guinea. The incidence and timing of infection in children born in a rural area of the Democratic Republic of Congo was investigated. TTV viremia was detected in 61 (58%) of 105 women attending an antenatal clinic and in 36 (54%) of 68 infants.

Variation of hepatitis C virus following serial transmission: multiple mechanisms of diversification of the hypervariable region and evidence for convergent genome evolution.

We have studied the evolution of hepatitis C virus (HCV) from a common source following serial transmission from contaminated batches of anti-D immunoglobulin. Six secondary recipients were each infected with virus from identifiable primary recipients of HCV-contaminated anti-D immunoglobulin. Phylogenetic analysis of virus E1/E2 gene sequences [including the hypervariable region (HVR)] and part of NS5B confirmed their common origin, but failed to reproduce the known epidemiological relationships between pairs of viruses, probably because of the frequent occurrence of convergent substitutions at both synonymous and nonsynonymous sites.

Infrequent detection of TT virus infection in intravenous drug users, prostitutes, and homosexual men.

TT virus (TTV), a recently discovered DNA virus, has been implicated as a cause of non-A to non-C posttransfusion hepatitis. The frequency of TTV in persons considered at high risk for sexual and parenteral infection was investigated (52 prostitutes, 81 homosexual men, 65 intravenous drug users) to assess its mode of transmission. TTV DNA was assayed by polymerase chain reaction using primers from conserved regions in the N22 clone.

Detection of Chlamydia trachomatis in genital swabs: comparison of commercial and in house amplification methods with culture.

Aims: To evaluate the sensitivity of the Roche Cobas, Roche Amplicor plate kit, ligase chain reaction (LCR), and an in house polymerase chain reaction (PCR) by titration of purified elementary bodies (EB) and also to test 245 urethral and endocervical specimens for Chlamydia trachomatis by the four assays as well as conventional culture.

Study Design: EB titrations were run in duplicate in each commercial assay and six times in the in house PCR. Clinical samples were aliquoted and tested by each assay and were considered positive if C trachomatis was detected by two or more separate tests or if the sample was either culture or immunofluorescence positive.

Detection of GB virus C RNA by GBV-C LCx and two PCR assays with primers from the 5' non-coding and NS5B region.

The objective of this study was to compare the sensitivity of three different reverse transcriptase-polymerase chain reaction (RT-PCR) based tests, for detection of GB virus C (GBV-C) RNA. One commercial and two 'in house' RT-PCR assays were employed in the testing of serum samples from 114 chronic hepatitis C infected individuals. A part of the 5' non-coding region (5'NCR) of the GBV-C genome was amplified by the GBV-C LCx assay (Abbott) and one of the 'in house' RT-PCR tests.

Serological Genotyping Using Synthetic Peptides Derived from the NS4 Region.

The RNA genome of hepatitis C virus (HCV) displays extensive sequence variation, and consequently, the virus is classified into six major genotypes. The severity of disease and response to antiviral treatment are thought to be influenced by both viral and host-related factors, including age of aquisition, duration of infection, circulating virus load, and the genotype of infecting virus Many investigators have reported that infections with HCV type 1 are associated with an increase in the likelihood of progression to hepatocellular carcinoma (1-3), and with nonresponsiveness to interferon therapy when compared to genotypes 2 or 3 (reviewed in refs. 4,5) This discovery emphasizes the need for genotyping methods in current clinical practice, in providing a predictor of the outcome of treatment, and perhaps helping to target appropriate treatment to the most relevant patient groups.

Determination of HCV Genotypes by RFLP.

Several different methods have been developed for the typing of HCV variants: direct sequence analysis, slot-blot hybridization analysis of reverse transcriptase-polymerase chain reaction (RT-PCR) products using cDNA probes specific to each HCV genotype and PCR amplification using type-specific primers that are designed to match only virus sequences of a defined HCV type and will fail to amplify sequences of other types. An alternative method is the nonselective amplification of virus cDNA using conserved primers followed by restriction fragment length polymorphisms (RFLP) The coding regions of the HCV genome are highly variable, so reliable amplification of different HCV genotypes with the same set of primers is difficult. For this reason, typing methods based on analysis of amplified DNA are more reliable if carried out in the highly conserved 5' noncoding region (5' NCR).

Hepatitis C virus : types, subtypes, and beyond.

Non-A, non-B hepatitis was recognized as a frequent consequence of blood transfusion for many years before the agent responsible, hepatitis C virus (HCV), was first cloned and sequenced in 1989 Very quickly it became apparent that viruses from different parts of the world were distinct, and after a frenzy of sequence analysis, a general picture has now emerged (1). Virus sequences can be divided into major types (identified by numbers) with nucleotide identities of <70% over complete genome sequences. Each type can be subdivided into subtypes (identified by letters) with identities of between 70 and 80%.

HIV encephalitis, proviral load and dementia in drug users and homosexuals with AIDS. Effect of neocortical involvement.

In this consecutive autopsy study, the pathological evidence of HIV encephalitis, which included the presence of giant cells and/or HIV p24 immunopositivity, was found more frequently in drug users (25 of 45; 56%) than in homosexual men (6 of 35; 17%) with AIDS (P < 0.01). Productive infection, as shown by HIV p24 positivity, was found in frontal lobe white matter in 29 of the 31 HIV encephalitis cases, but was also present in grey matter in 50% of the HIV encephalitis cases.

Prevalence, incidence, and clinical characteristics of hepatitis G virus/GB virus C infection in Scottish blood donors.

The prevalence, incidence, clinical features, and natural history of hepatitis G virus (HGV) or GB virus C (GBV-C) were investigated in a non-remunerated blood donor population to determine its clinical significance and its impact on blood safety. Of 1020 regular blood donors, 23 (2.25%) were positive for plasma HGV/GBV-C RNA.

Transfusion virology: progress and challenges.

Discoveries of new human viruses and new technologies for their detection have made, and will continue to make, major contributions to the safety of blood transfusion. This article discusses the practical issues involved in the implementation of additional serological screening tests for viruses such as human T-lymphotropic virus, and reviews current information on the prevalence and pathogenicity of more recently discovered viruses, such as hepatitis G virus (HGV) or GB virus-C (GBV-C) and human herpes virus 8, a potential aetiological agent of Kaposi's sarcoma. Progress in the technology behind nucleic acid amplification techniques, such as the polymerase chain reaction (PCR), makes direct detection of viruses such as human immunodeficiency virus and hepatitis C virus possible.

Detection in chimpanzees of a novel flavivirus related to GB virus-C/hepatitis G virus.

Infection with hepatitis G virus (HGV) or GB virus-C (GBV-C) is widely distributed in human populations. Viruses related to GBV-C/HGV have been recovered from several New World primate species, including tamarins, owl monkeys and marmosets. To understand more about the relationship between GB viruses and their hosts, we used primers from the 5' non-coding (5'NC), non-structural 3 (NS3) and NS5 regions in nested polymerase chain reactions to screen for related viruses infecting non-captive chimpanzees (Pan troglodytes, troglodytes and verus subspecies).

Detection of a novel DNA virus (TTV) in blood donors and blood products.

Background: A newly discovered DNA virus, transfusion-transmitted virus (TTV), has been implicated as a cause of post-transfusion hepatitis. We investigated the frequency of TTV viraemia in UK blood donors, and the extent to which TTV contaminates blood products such as factor VIII and IX clotting factors. We also investigated the possible aetiological role of TTV in cryptogenic fulminant hepatic failure (FHF).

Sexual transmission of GB virus C/hepatitis G virus.

Although it is established that infection with GB virus C (GBV-C) or hepatitis G virus (HGV) can be transmitted parenterally, the prevalence of GBV-C/HGV viremia in the general population (2-5%) is relatively high compared with other parenterally borne viruses such as hepatitis C virus. To investigate the possibility of sexual transmission of GBV-C/HGV, we determined the frequency of viremia by the polymerase chain reaction and serological reactivity to the E2 protein by ELISA in samples collected from individuals at risk for sexually transmitted diseases attending a city genitourinary medicine clinic. GBV-C/HGV viremia was detected in 27 of 87 male homosexuals (31%) and 9 of 50 prostitutes (18%), frequencies significantly greater than those in matched controls (2/63) and local blood donors (2.

Clinical significance of intrahepatic hepatitis C virus levels in patients with chronic HCV infection.

Background: The clinical significance of a single assessment of circulating hepatitis C virus (HCV) RNA and its relation to the level of intrahepatic HCV RNA remains unclear.

Aims: To investigate the relation between intrahepatic HCV levels and clinicopathological characteristics of chronic HCV infection.

Patients: Ninety eight consecutive patients with chronic HCV infection were studied; none had received alpha interferon therapy.

Long-term evolution of the hypervariable region of hepatitis C virus in a common-source-infected cohort.

The long-term evolution of the hepatitis C virus hypervariable region (HVR) and flanking regions of the E1 and E2 envelope proteins have been studied in a cohort of women infected from a common source of anti-D immunoglobulin. Whereas virus sequences in the infectious source were relatively homogeneous, distinct HVR variants were observed in each anti-D recipient, indicating that this region can evolve in multiple directions from the same point. Where HVR variants with dissimilar sequences were present in a single individual, the frequency of synonymous substitution in the flanking regions suggested that the lineages diverged more than a decade previously.

High prevalence of hepatitis G virus infection in multiply transfused children with thalassaemia.

We investigated the prevalence of hepatitis G virus (HGV) RNA in relation to the frequency of blood transfusions in thalassaemic children and in volunteer blood donors in Thailand. Furthermore, we studied the frequency of coinfection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) as well as a possible relationship to the alanine aminotransferase (ALT) status of the blood samples, taken at random from thalassaemic children who have received multiple blood transfusions and from volunteer blood donors. The results show detectable HGV-RNA in 32.

Low level or absent in vivo replication of hepatitis C virus and hepatitis G virus/GB virus C in peripheral blood mononuclear cells.

To investigate which subsets of peripheral blood mononuclear cells (PBMCs) are susceptible to infection with hepatitis C virus (HCV) and hepatitis G virus (HGV) or GB virus C (GBV-C), a PCR-based assay using tagged primers in the core region (HCV) and NS3 region (HGV/GBV-C) for the specific detection of negative strand (replicating) viral RNA sequences was developed. In liver biopsy samples both positive and negative strands of HCV RNA were detected, at levels ranging from 3 to 11 x 10(6) RNA copies per 10(6) cells and 3.7-4.