Sexual transmission of GB virus C/hepatitis G virus

Human Pegivirus Type 1: A Common Human Virus That Is Beneficial in Immune-Mediated Disease?

Two groups identified a novel human flavivirus in the mid-1990s. One group named the virus hepatitis G virus (HGV) and the other named it GB Virus type C (GBV-C). Sequence analyses found these two isolates to be the same virus, and subsequent studies found that the virus does not cause hepatitis despite sharing genome organization with hepatitis C virus. Although HGV/GBV-C infection is common and may cause persistent infection in humans, the virus does not appear to directly cause any other known disease state. Thus, the virus was renamed “human pegivirus 1” (HPgV-1) for “persistent G” virus. HPgV-1 is found primarily in lymphocytes and not hepatocytes, and several studies found HPgV-1 infection associated with prolonged survival in people living with HIV. Co-infection of human lymphocytes with HPgV-1 and HIV inhibits HIV replication. Although three viral proteins directly inhibit HIV replication in vitro, the major effects of HPgV-1 leading to reduced HIV-related mortality appear to result from a global reduction in immune activation. HPgV-1 specifically interferes with T cell receptor signaling (TCR) by reducing proximal activation of the lymphocyte specific Src kinase LCK. Although TCR signaling is reduced, T cell activation is not abolished and with sufficient stimulus, T cell functions are enabled. Consequently, HPgV-1 is not associated with immune suppression. The HPgV-1 immunomodulatory effects are associated with beneficial outcomes in other diseases including Ebola virus infection and possibly graft-versus-host-disease following stem cell transplantation. Better understanding of HPgV-1 immune escape and mechanisms of inflammation may identify novel therapies for immune-based diseases.

Review of human pegivirus: Prevalence, transmission, pathogenesis, and clinical implication

Human pegivirus (HPgV-1), previously known as GB virus C (GBV-C) or hepatitis G virus (HGV), is a single-stranded positive RNA virus belonging to the genus Pegivirus of the Flaviviridae family. It is transmitted by percutaneous injuries (PIs), contaminated blood and/or blood products, sexual contact, and vertical mother-to-child transmission. It is widely prevalent in general population, especially in high-risk groups. HPgV-1 viremia is typically cleared within the first 1–2 years of infection in most healthy individuals, but may persist for longer periods of time in immunocompromised individuals and/or those co-infected by other viruses. A large body of evidences indicate that HPgV-1 persistent infection has a beneficial clinical effect on many infectious diseases, such as acquired immunodeficiency syndrome (AIDS) and hepatitis C. The beneficial effects seem to be related to a significant reduction of immune activation, and/or the inhabitation of co-infected viruses (e.g. HIV-1). HPgV-1 has a broad cellular tropism for lymphoid and myeloid cells, and preferentially replicates in bone marrow and spleen without cytopathic effect, implying a therapeutic potential. The paper aims to summarize the natural history, prevalence and distribution characteristics, and pathogenesis of HPgV-1, and discuss its association with other human viral diseases, and potential use in therapy as a biovaccine or viral vector.

Prevalence of human pegivirus-1 and sequence variability of its E2 glycoprotein estimated from screening donors of fetal stem cell-containing material

Background

Human pegivirus-1 (HPgV-1) is a member of the Flaviviridae family whose genomic organization and mode of cellular entry is similar to that of hepatitis C virus (HCV). The E2 glycoprotein of HPgV-1 is the principle mediator in the virus-cell interaction and as such harbors most of HPgV-1’s antigenic determinants. HPgV-1 persists in blood cell precursors which are increasingly used for cell therapy.

Methods

We studied HPgV-1 prevalence in a large cohort of females donating fetal tissues for clinical use. PCR was used for screening and estimation of viral load in viremic plasma and fetal samples. Sequence analysis was performed for portions of the 5′-untranslated and E2 regions of HPgV-1 purified from donor plasmas. Sequencing was followed by phylogenetic analysis.

Results

HPgV-1 was revealed in 13.7% of plasmas, 5.0% of fetal tissues, 5.4% of chorions, exceeding the prevalence of HCV in these types of samples. Transmission of HPgV-1 occurred in 25.8% of traceable mother-chorion-fetal tissues triads. For HPgV-1-positive donors, a high viral load in plasma appears to be a prerequisite for transmission. However, about one third of fetal samples acquired infection from non-viremic individuals. Sequencing of 5′-untranslated region placed most HPgV-1 samples to genotype 2a. At the same time, a portion of E2 sequence provided a much weaker support for this grouping apparently due to a higher variability. Polymorphisms were detected in important structural and antigenic motifs of E2.

Conclusion

HPgV-1 is efficiently transmitted to fetus at early embryonic stages. A high variability in E2 may pose a risk of generation of pathogenic subtypes. Although HPgV-1 is considered benign and no longer tested mandatorily in blood banks, the virus may have adversary effects at target niches if delivered with infected graft upon cell transplantation. This argues for the necessity of HPgV-1 testing of cell samples aimed for clinical use.

GBV-C/HIV-1 coinfection is associated with low HIV-1 viral load and high CD4+ T lymphocyte count

GB virus C (GBV-C) is a lymphotropic virus with a low level or non-existent replication in the liver. The interaction between HIV-1 and GBV-C apparently reduces the progression of HIV-1 infection to AIDS and improves the quality of life of HIV-1 infected individuals. A cross-sectional study was established to determine the possible effect of HIV-1/GBV-C coinfection on HIV-1 viral load and CD4⁺ T lymphocyte counts. Samples from 313 HIV-1 infected persons from the Virus Laboratory of the Federal University of Pará as well as demographic and clinical information were obtained from medical records. This study used a nested PCR method to determine GBV-C viremia. The prevalence of HIV-1/GBV-C coinfection was 17%. There were no significant differences in the distribution according to age, sex or ethnicity between the groups. The differences in HIV-1 viral load and CD4⁺ T lymphocyte count between the HIV-1 and HIV-1/GBV-C groups were highly significant, indicating that coinfection results in lower viral loads and higher CD4⁺ T lymphocyte counts compared to HIV-1 mono-infection. The results indicate a protective effect among coinfected individuals.

Evaluation of Viremia Frequencies of a Novel Human Pegivirus by Using Bioinformatic Screening and PCR

Bioinformatic screening and PCR-based approaches detected active infection with human hepegivirus-1 in exposed populations.

Next-generation sequencing has critical applications in virus discovery, diagnostics, and environmental surveillance. We used metagenomic sequence libraries for retrospective screening of plasma samples for the recently discovered human hepegivirus 1 (HHpgV-1). From a cohort of 150 hepatitis C virus (HCV)–positive case-patients, we identified 2 persons with HHpgV-1 viremia and a high frequency of human pegivirus (HPgV) viremia (14%). Detection of HHpgV-1 and HPgV was concordant with parallel PCR-based screening using conserved primers matching groups 1 (HPgV) and 2 (HHPgV-1) nonstructural 3 region sequences. PCR identified 1 HHPgV-1–positive person with viremia from a group of 195 persons with hemophilia who had been exposed to nonvirally inactivated factor VII/IX; 18 (9%) were HPgV-positive. Relative to HCV and HPgV, active infections with HHpgV-1 were infrequently detected in blood, even in groups that had substantial parenteral exposure. Our findings are consistent with lower transmissibility or higher rates of virus clearance for HHpgV-1 than for other bloodborne human flaviviruses.

Evidence for Within-Host Genetic Recombination among the Human Pegiviral Strains in HIV Infected Subjects

The non-pathogenic Human Pegivirus (HPgV, formerly GBV-C/HGV), the most prevalent RNA virus worldwide, is known to be associated with reduced morbidity and mortality in HIV-infected individuals. Although previous studies documented its ubiquity and important role in HIV-infected individuals, little is known about the underlying genetic mechanisms that maintain high genetic diversity of HPgV within the HIV-infected individuals. To assess the within-host genetic diversity of HPgV and forces that maintain such diversity within the co-infected hosts, we performed phylogenetic analyses taking into account 229 HPgV partial E1-E2 clonal sequences representing 15 male and 8 female co-infected HIV patients from Hubei province of central China. Our results revealed the presence of eleven strongly supported clades. While nine clades belonged to genotype 3, two clades belonged to genotype 2. Additionally, four clades that belonged to genotype 3 exhibited inter-clade recombination events. The presence of clonal sequences representing multiple clades within the HIV-infected individual provided the evidence of co-circulation of HPgV strains across the region. Of the 23 patients, six patients (i.e., five males and one female) were detected to have HPgV recombinant sequences. Our results also revealed that while male patients shared the viral strains with other patients, viral strains from the female patients had restricted dispersal. Taken together, the present study revealed that multiple infections with divergent HPgV viral strains may have caused within-host genetic recombination, predominantly in male patients, and therefore, could be the major driver in shaping genetic diversity of HPgV.

Durable sequence stability and bone marrow tropism in a macaque model of human pegivirus infection

Human pegivirus (HPgV)-formerly known as GB virus C and hepatitis G virus-is a poorly characterized RNA virus that infects about one-sixth of the global human population and is transmitted frequently in the blood supply. We create an animal model of HPgV infection by infecting macaque monkeys with a new simian pegivirus (SPgV) discovered in wild baboons. Using this model, we provide a high-resolution, longitudinal picture of SPgV viremia where the dose, route, and timing of infection are known. We detail the highly variable acute phase of SPgV infection, showing that the viral load trajectory early in infection is dependent on the infecting dose, whereas the chronic-phase viremic set point is not. We also show that SPgV has an extremely low propensity for accumulating sequence variation, with no consensus-level variants detected during the acute phase of infection and an average of only 1.5 variants generated per 100 infection-days. Finally, we show that SPgV RNA is highly concentrated in only two tissues: spleen and bone marrow, with bone marrow likely producing most of the virus detected in plasma. Together, these results reconcile several paradoxical observations from cross-sectional analyses of HPgV in humans and provide an animal model for studying pegivirus biology.

Detection of GB virus C genomic sequence in the cerebrospinal fluid of a HIV-infected patient in China: a case report and literature review

Hepatitis G virus or GB virus C (GBV-C) is a human virus of the Flaviviridae family that is structurally and epidemiologically closest to hepatitis C virus, but replicates primarily in lymphocytes. Co-infection with GBV-C has been reported to confer beneficial outcomes in some HIV-positive patients. Up to now, however, studies on GBV-C infection in the central nervous system (CNS) of HIV-infected patient have rarely been reported. Herein, we report on a 32-year-old HIV-1-infected patient with cerebral toxoplasmosis and fungal encephalitis. GBV-C viral loads were detected in CSF by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR), and the results showed that GBV-C viral load was 6·5 log copies/ml. We amplified and sequenced the E2 and 5'-untranslated regions from the purified viral RNA from CSF by RT-PCR. Both sequences belong to genotype 3 and there were some minor nucleotide divergence among the E2 sequences from the CSF of the patient. These data suggest that GBV-C may be able to penetrate the blood-brain barrier and colonize the CNS of HIV-infected patients. However, the exact mechanisms and potential effect of the infected GBV-C in CNS on HIV-associated neuropathy needs to be further explored.

Downregulation of Cytokines and Chemokines by GB Virus C After Transmission Via Blood Transfusion in HIV-Positive Blood Recipients

BACKGROUND

An association between GB virus C (GBV-C) and improved outcomes of human immunodeficiency virus (HIV) infection has been reported in HIV-positive individuals with active GBV-C coinfection. This study provides insights into the immune mechanisms underlying the protective role of GBV-C in HIV-infected patients.

METHODS

The concentrations of 64 cytokines and chemokines were measured in plasma samples obtained from the Viral Activation Transfusion Study cohort before transfusion and longitudinally from 30 patients positive for both HIV and GBV-C (hereafter, "cases") and 30 patients positive for HIV and negative for GBV-C (hereafter, "controls").

RESULTS

Cases had lower HIV viral loads and higher CD4 T-cell counts than controls after acquisition of GBV-C infection. Most of the modulated cytokines and chemokines were reduced after GBV-C detection, including many proinflammatory cytokines, suggesting an overall antiinflammatory effect of GBV-C in HIV-positive subjects. Most pathways and functions of the measured cytokines were downregulated in cases, except cell death pathways, which were upregulated in various cell subsets in the 3 months after GBV-C detection.

CONCLUSIONS

GBV-C has a protective effect, in part through a competition mechanism leading to decreased inflammation and improved HIV disease outcome in cases. Further studies are necessary to establish whether GBV-C may have deleterious effects on the host at the cellular level, including depleting the cells that are the targets of HIV.

Viraemic frequencies and seroprevalence of non-primate hepacivirus and equine pegiviruses in horses and other mammalian species

Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 horses screened for antibodies to NS3 and core antibodies, of which three were viraemic by PCR. All five horses that were stablemates of a viraemic horse were seropositive, as was a dog on the same farm. With this single exception, all other species were negative for NPHV antibodies and viraemia: donkeys (n=100), dogs (n=112), cats (n=131), non-human primates (n=164) and humans (n=362). EPgV antibodies to NS3 were detected in 66.5% of horses, including 10 of the 12 horses that had EPgV viraemia. All donkey samples were negative for EPgV antibody and RNA. All horse and donkey samples were negative for TDAV RNA. By comparing viraemia frequencies in horses with and without liver disease, no evidence was obtained that supported an association between active NPHV and EPgV infections with hepatopathy. The study demonstrates that NPHV and EPgV infections are widespread and enzootic in the study horse population and confirms that NPHV and potentially EPgV have higher frequencies of viral clearance than HCV and HPgV infections in humans.

Human pegivirus (GB virus C) NS3 protease activity inhibits induction of the type I interferon response and is not inhibited by HCV NS3 protease inhibitors

We previously found that human pegivirus (HPgV; formerly GBV-C) NS3 protease activity inhibits Human Immunodeficiency Virus (HIV) replication in a CD4+ T cell line. Given the protease׳s similarity to the Hepatitis C virus (HCV) NS3 protease, we characterized HPgV protease activity and asked whether it affects the type I interferon response or is inhibited by HCV protease antagonists. We characterized the activity of proteases with mutations in the catalytic triad and demonstrated that the HCV protease inhibitors Telaprevir, Boceprevir, and Danoprevir do not affect HPgV protease activity. HPgV NS3 protease cleaved MAVS but not TRIF, and it inhibited interferon responses sufficiently to enhance growth of an interferon-sensitive virus. Therefore, HPgV׳s inhibition of the interferon response could help promote HPgV persistence, which is associated with clinical benefits in HIV-infected patients. Our results also imply that HCV protease inhibitors should not interfere with the beneficial effects of HPgV in HPgV/HCV/HIV infected patients.

Role of GB virus C in modulating HIV disease

GB virus C (GBV-C) is a member of the Flaviviridae family and the most closely related human virus to HCV. However, GBV-C does not replicate in hepatocytes, but rather in lymphocytes. GBV-C has a worldwide distribution and is transmitted sexually, parenterally and through mother-to-child transmission. Thus, co-infection with HCV and HIV is common. Until now, no human disease has been associated with GBV-C infection. However, there are several reports of a beneficial effect of GBV-C on HIV disease progression in vivo. Different mechanisms to explain these observations have been proposed, including modification of antiviral cytokine production, HIV co-receptor expression, direct inhibition of HIV-1 entry, T-cell activation and Fas-mediated apoptosis. Further understanding of these mechanisms may open new strategies for the treatment of HIV/AIDS.

Acquisition of GB virus type C and lower mortality in patients with advanced HIV disease

BACKGROUND

GB virus type C (GBV-C) is transmitted by sexual or parenteral exposure and is prevalent among patients receiving blood products. GBV-C is associated with lower human immunodeficiency virus (HIV) RNA and better survival among HIV-infected patients. Open questions are the presence and the direction of any causal relationship between GBV-C infection and HIV disease markers in the context of highly active antiretroviral therapy (HAART).

METHODS

We used a limited access database obtained from the National Heart, Lung, and Blood Institute's Viral Activation Transfusion Study (VATS), a randomized controlled trial of leukoreduced vs nonleukoreduced transfusions to HIV-infected transfusion-naive patients. Blood samples from 489 subjects were tested for GBV-C markers. Cox regression models and inverse probability of treatment weights were used to examine the association between GBV-C coinfection and mortality in the VATS cohort.

RESULTS

We found a significant reduction in mortality among GBV-C coinfected VATS subjects, after adjusting for HAART status, HIV RNA level, and CD4 cell count at baseline. Acquisition of GBV-C RNA (n = 39) was associated with lower mortality in 294 subjects who were GBV-C negative at baseline, adjusting for baseline covariates (hazard ratio = 0.22, 95% confidence interval [CI]: .08-.58) and in models in which weights were used to control for time-updated covariates (odds ratio = 0.21, 95% CI: .08-.60).

CONCLUSIONS

GBV-C viremia is associated with lower mortality, and GBV-C acquisition via transfusion is associated with a significant reduction in mortality in HIV-infected individuals, controlling for HIV disease markers. These findings provide the first evidence that incident GBV-C infection alters mortality in HIV-infected patients.

Transmission of GB virus type C via transfusion in a cohort of HIV-infected patients

BACKGROUND

GB virus C (GBV-C) infection is transmitted by blood exposure and associated with lower human immunodeficiency virus (HIV) load and slower HIV disease progression. Few studies describe predictors of acute GBV-C infection following transfusion in HIV-infected patients.

METHODS

We used a limited-access database from the National Heart Lung and Blood Institute's Viral Activation Transfusion Study, a randomized controlled trial of leukoreduced versus nonleukoreduced transfusions received by HIV-infected, transfusion-naive patients. Blood samples from 489 subjects were tested for GBV-C markers in pretransfusion and posttransfusion samples. We estimated the risk of acquiring GBV-C RNA and predictors of GBV-C acquisition, using pooled logistic regression.

RESULTS

GBV-C RNA was detected ≤120 days following the first transfusion in 22 (7.5%) of 294 subjects who were GBV-C negative before transfusion. The risk of GBV-C RNA acquisition increased with each unit transfused (odds ratio, 1.09; 95% confidence interval, 1.06-1.11). Lower baseline HIV load and use of antiretroviral therapy were associated with subsequent GBV-C RNA acquisition, after control for units of blood transfused. Leukoreduced status of transfused units was not associated with GBV-C transmission.

CONCLUSIONS

Blood transfusion is associated with a significant risk of GBV-C acquisition among HIV-infected patients. Transmission of GBV-C by blood transfusion was inversely related to HIV load.

Prevalence and clinical significance of GB virus type C/hepatitis G virus coinfection in patients with chronic hepatitis C undergoing antiviral therapy

Coinfection with GBV-C/HGV in patients with chronic hepatitis C (CHC) may influence clinical course and response rates of antiviral therapy. Aim of the study was to investigate the prevalence of GBV-C/HGV/HCV coinfection and its influence on outcome of interferon/ribavirin combination therapy. Three hundred and four patients with CHC [m/f = 211/93, age: 42 (18-65)] were investigated. HGV RNA detection was performed by polymerase chain reaction prior to and 6 months after the end of antiviral therapy. HGV/HCV coinfection could be identified in 37/304 (12.2%) patients with intravenous drug abuse as the most common source of infection (N = 21, (56.8%)). The predominant HCV genotype in coinfected individuals was HCV-3a (HCV-3a: 51.4%, HCV-1: 37.8%, HCV-4: 10.8%). HGV coinfection was more prevalent in patients infected with HCV-3 compared to HCV-1 or HCV-4 [19/45 (42.2%) vs. 14/185 (7.6%) vs. 4/52 (7.7%), P < 0.01]. Patients with HGV/HCV coinfection were younger [35 (18-56) vs. 43 (19-65), years; P < 0.01], and advanced fibrosis (F3-F4) was less frequent (22.2% vs. 42.9%, P < 0.05). A sustained virological response was achieved more frequently in HGV/HCV coinfected patients [26/37 (70.3%)] than in monoinfected patients [120/267 (44.9%), P < 0.01]. HGV RNA was undetectable in 65.7% of the coinfected patients at the end of follow-up. Intravenous drug abuse seems to be a major risk factor for HGV coinfection in patients with chronic hepatitis C. Coinfection with HGV does not worsen the clinical course of chronic hepatitis C or diminish response of HCV to antiviral therapy. Interferon/ribavirin combination therapy also clears HGV infection in a high proportion of cases.

The GB viruses: a review and proposed classification of GBV-A, GBV-C (HGV), and GBV-D in genus Pegivirus within the family Flaviviridae

In 1967, it was reported that experimental inoculation of serum from a surgeon (G.B.) with acute hepatitis into tamarins resulted in hepatitis. In 1995, two new members of the family Flaviviridae, named GBV-A and GBV-B, were identified in tamarins that developed hepatitis following inoculation with the 11th GB passage. Neither virus infects humans, and a number of GBV-A variants were identified in wild New World monkeys that were captured. Subsequently, a related human virus was identified [named GBV-C or hepatitis G virus (HGV)], and recently a more distantly related virus (named GBV-D) was discovered in bats. Only GBV-B, a second species within the genus Hepacivirus (type species hepatitis C virus), has been shown to cause hepatitis; it causes acute hepatitis in experimentally infected tamarins. The other GB viruses have however not been assigned to a genus within the family Flaviviridae. Based on phylogenetic relationships, genome organization and pathogenic features of the GB viruses, we propose to classify GBV-A-like viruses, GBV-C and GBV-D as members of a fourth genus in the family Flaviviridae, named Pegivirus (pe, persistent; g, GB or G). We also propose renaming 'GB' viruses within the tentative genus Pegivirus to reflect their host origin.

GB virus C genotype 2 predominance in a hepatitis C virus/HIV infected population associated with reduced liver disease

BACKGROUND AND AIM

GB virus C (GBV-C) infection in hepatitis C virus (HCV)/HIV co-infection is associated with a significant reduction in the severity of HCV-related liver disease. The role of GBV-C genotype in this association is unknown. It has been suggested that GBV-C genotype may influence CD4 positive T-cell counts in HCV/HIV co-infected patients. The aim of the present study was to identify the GBV-C genotype in a HCV/HIV co-infected population and determine if the GBV-C genotype contributes to a reduction in HCV-related liver disease.

METHODS

GBV-C RNA from 57 patients who were co-infected with HCV/HIV was analyzed. GBV-C RNA was detected by reverse transcription-polymerase chain reaction with primers to the NS5B gene and genotype determined by phylogenetic analysis after sequencing using E2 gene primers.

RESULTS

Genotype 2 was the predominant isolate in our population and was detected in 50/56 (89.3%) of patients, although sequences with similarity to genotypes 1, 3, 4 and 5 were also identified. There was no statistical difference between CD4 positive T-cell counts in the GBV-C genotype 2 and non-genotype 2 groups.

CONCLUSIONS

The GBV-C genotype distribution in our HCV/HIV patient group was consistent with that reported in other developed countries. The predominance of genotype 2 in this study meant that we could not draw a conclusion for the role of GBV-C genotype in the reduced severity of liver disease in co-infected patients but CD4 positive T-cell counts appeared to be unaffected by GBV-C genotype.

Reduction in hepatitis C-related liver disease associated with GB virus C in human immunodeficiency virus coinfection

BACKGROUND & AIMS

It has been reported that GB virus C infection (GBV-C) leads to improved morbidity and mortality in patients with human immunodeficiency virus (HIV) infection. However, GBV-C has no effect on the course of liver disease in hepatitis C virus (HCV) monoinfection. The aim of the study was to determine the influence of GBV-C infection on liver disease in patients with HCV/HIV coinfection.

METHODS

Data on 158 HCV/HIV patients were collected from January 1996 to October 2005. Two plasma specimens, collected at least 18 months apart, were tested for GBV-C RNA by reverse transcription-polymerase chain reaction with primers to the NS5B gene and confirmed using E2 gene primers and sequencing. Antibodies to GBV-C E2 protein were also determined. Liver-related morbidity and mortality were assessed from patient records.

RESULTS

Fifty-seven of 158 (36%) patients had GBV-C RNA and 94 (59%) had evidence of exposure to GBV-C based on combined polymerase chain reaction and antibody results. Thirty-four (21%) patients had features of cirrhosis, with 20 having compensated and 14 having decompensated cirrhosis. Active GBV-C RNA was significantly associated with a reduction in cirrhosis, both compensated and decompensated in multivariate analysis (hazard ratio, 0.27; 95% confidence interval, 0.08-0.88; P = .03), as well as in analysis for cirrhosis-free survival vs duration of HCV infection (P = .006). No significant effect on liver-related or overall survival was observed.

CONCLUSIONS

In these HCV/HIV-coinfected patients, GBV-C RNA was associated with a significant reduction in the severity of HCV-related liver disease.

GB virus C: insights into co-infection

GB virus C (GBV-C) is a single stranded positive sense RNA virus, which is a member of the Flaviviridae. It has a close sequence homology and genomic organisation to hepatitis C virus (HCV). However, unlike HCV it is not hepatotrophic. GBV-C replicates within cells of the haemopoietic lineage, in particular lymphocytes. No disease has been associated with GBV-C infection but co-infection with human immunodeficiency virus (HIV) leads to improved morbidity and mortality for the HIV infected individual and slows progression to acquired immunodeficiency syndrome. This potential benefit of GBV-C has been demonstrated in the pre and post highly active anti-retroviral treatment (HAART) eras. GBV-C has been found to decrease HIV replication in in vitro models. The mechanism of the beneficial effect of GBV-C appears to be mediated by alterations in the cellular immune response, the details of which remain unclear. Despite this, there continues to be controversy regarding the influence of GBV-C on HIV as several reports have questioned the beneficial effect. GBV-C does not appear to influence liver related disease in subjects co-infected with HCV or hepatitis B virus (HBV). Combination of HIV and HCV leads to accelerated liver disease. The influence of GBV-C in this situation is yet to be determined. Elucidation of the putative protective effect of GBV-C in HIV co-infection could potentially identify novel targets for anti-HIV therapeutics and lead to the development of disease modifying vaccines.

Male to male sex is associated with a high prevalence of exposure to GB virus C

Co-infection with GB virus C (GBV-C) and human immunodeficiency virus (HIV) appears to reduce mortality for HIV/AIDS. Epidemiological and demographic factors for GBV-C were examined prospectively in 167 subjects at risk for co-infection. We attempted to establish a hierarchical exposure risk for GBV-C. Overall exposure to GBV-C was 45.5%. In univariate analysis, GBV-C was associated with male to male sex (P<0.0001), HIV infection (P=0.0005) and hepatitis B infection (P=0.006). Injecting drug use approached statistical significance (P=0.08) while being a female sex worker was not associated with GBV-C exposure/infection (P=0.85). Exposure to GBV-C in 192 healthy blood donors was found to be 9.4%. In conclusion, the data suggest that male to male sex is a more effective mode of transmission of GBV-C and that GBV-C is associated with HIV co-infection. As male to male sex is also a risk factor for HIV transmission our data suggest that many may benefit from the potential protective effect GBV-C exerts on HIV-infected persons.

GB virus C coinfection and vertical transmission in HIV-infected mothers before the introduction of antiretroviral prophylaxis

OBJECTIVES

To investigate the prevalence of GB virus C (GBV-C) viraemia and GBV-C antibodies in a cohort of HIV-infected mothers and their infants between 1987 and 1994.

METHODS

GBV-C viraemia and antibodies were determined by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) in 52 HIV-infected mothers and their 53 infants, who were born before antiretroviral prophylaxis for reduction of HIV transmission was introduced at the end of 1994. Ten of these children acquired HIV.

RESULTS

Mothers of three children had GBV-C viraemia and mothers of another 14 children carried antibodies against GBV-C. No mother had GBV-C antibodies and GBV-C viraemia simultaneously. GBV-C viraemia was detected in only one infant. This child was delivered by the vaginal route to a mother with GBV-C viraemia, and was not HIV-infected. No vertical transmission of GBV-C occurred from mothers with GBV-C antibodies. However, four of 10 children who were infected with HIV had a mother with past or ongoing GBV-C infection.

CONCLUSION

Our findings suggest that the risk of vertical transmission of GBV-C is not elevated in HIV-infected mothers. Furthermore, although the number of HIV-1-infected children was low, we saw no evidence that the presence of ongoing or past GBV-C infection influenced the probability of vertical HIV transmission.

[Hepatitis G virus and labile blood products: role of transfusional transmission]

The GBV-C/HGV (HGV) virus was discovered a few years ago. This virus is known to be parenterally as well as sexually transmitted. However, no study has found some pathogenic roles for HGV so far. In the present study, we aimed to investigate the transmission of HGV by blood components transfused to 284 patients hospitalized in surgery unit in 1995. We tested two parameters of infection in blood components transfused to infected recipients: viral RNA by PCR and anti-E2 antibodies by ELISA. We tried to suspect some potent hepatocyte impacts by assessing the levels of two enzymes in serums: alanine aminotransferase (ALT) and alpha-glutathion S-transferase (alpha-GST). We found that HGV-RNA was detectable in 3.6% of recipients prior to transfusion and 7.5% post-transfusion. For each infected recipient, we retrospectively did a search for HGV-RNA in each transfused blood component, and we found at least one blood component as HGV-RNA-positive for each transfusional infected recipient. Anti-E2 antibody prevalence standing for a former and cured infection was 39.6% in all the recipients. In viremic recipients, ALT levels were mostly normal, while alpha-GST levels were found more commonly elevated than in non-viremic recipients although non-significantly (20% vs. 6.3%; P = 0.07). The present study underlines that HGV transmission is mostly transfusional in surgery units, and that infectiosity of blood components can be anticipated by detection of the viral RNA by PCR. Furthermore, the possible relationship between the serum activity of alpha-GST and the hepatotropism of HGV, although non-admitted as pathogenic, should be investigated.

Prevalence of infection and genotypes of GBV-C/HGV among homosexual men

Since the discovery of GB virus-C (GBV-C) and hepatitis G virus (HGV), many studies have been performed. These viruses are now known to be parenterally, as well as sexually transmitted. A phylogenetic analysis also revealed that GBV-C has five major genotypes: type 1 predominates in West Africa, type 2 in Europe and the United States, type 3 in parts of Asia, type 4 in Southeast Asia, and type 5 in South Africa. Despite the number of reports so far, there have been few large-scale surveys of homosexual men to determine the prevalence of the GBV-C/HGV infections. We examined the levels of GBV-C/HGV viremia in 297 homosexual men who attended the Nagoya Lesbian and Gay Revolution held in Nagoya, Japan. Reverse transcription-polymerase chain reaction (RT-PCR)/nested PCR of the GBV-C/HGV 5 ' -non-coding region (NCR), and base sequence analyses showed that the infection rate was 12.5%, and genotypes in this population were classified into type 2 (32%) and type 3 (68%). None were classified as types 1, 4, or 5 in this study. Our results indicate that the GBV-C/HGV type 2 seen mainly in Europe and the US is spreading widely in Japan, especially in the Nagoya district.

Genotype distribution of the GB virus C in citizens of São Paulo City, Brazil

There has been several studies worldwide on phylogenetics and genotype distribution of the GB-virus C / Hepatitis G virus (GBV-C/HGV). However, in their great majority, those investigations were based on some epidemiologically linked group, rather than on a representative sampling of the general population. The present is a continuation of the first study in Brazil with such a population; it addresses the GBV-C/HGV phylogenetics and genotype distribution based on samples identified among more than 1,000 individuals of the city of S o Paulo. For this purpose, a 728 bp fragment of the 5 non-coding region (5 NCR) of the viral genome, from 24 isolates, was sequenced and subjected to phylogenetic analysis. Genotypes 1, 2a and 2b were found at 8.3% (2/24), 50% (12/24) and 41.7% (10/24), respectively. In conclusion S o Paulo displays a genotype distribution similar to the published data for other States and Regions of Brazil, endorsing the notion that types 1 and 2 would have entered the country with African and European people, respectively, since its earliest formation.

Prevalence of GBV-C infection among dental personnel

Healthcare workers who carry out exposure-prone procedures are theoretically at increased risk of acquiring blood-borne virus infections. GB virus C (GBV-C) is a recently described blood-borne virus that is related distantly to hepatitis C virus. The occupational risk of GBV-C infection to healthcare workers is unknown. This study collected detailed occupational and personal risk data in parallel with a blood specimen, to establish the prevalence and determinants of GBV-C infection among dental healthcare workers. The presence of GBV-C antibodies was detected using commercially available ELISA; GBV-C RNA was detected by nested PCR using primers from the conserved 5' noncoding region. The overall prevalence of GBV-C antibodies among the study population was 11.1% (98/880, 95% confidence interval [CI], 9.1-13.4%) and 4.6% were positive for GBV-C RNA (46/879, 95% CI, 2.5-5.1%), resulting in a cumulative prevalence of 15.7%. These figures are similar to those described in other populations. There was no significant difference in lifetime exposure to GBV-C between dentists (17.7%) and dental nurses/hygienists (14.3%). Significantly more dental nurses/hygienists aged 16-30 years had been exposed to GBV-C compared to dentists of the same age (chi(2) = 13.75; P < 0.001). Conversely, significantly more dentists 46 years or older had evidence of exposure to GBV-C compared to dental nurses/hygienists (chi(2) = 6.79; P = 0.009). The high prevalence of GBV-C infection did not seem to be related to past parenteral exposure, and the data suggest that sexual transmission, rather than occupational transmission, was a more important route for GBV-C infection among this population.

GB virus C epidemiology in Denmark: different routes of transmission in children and low- and high-risk adults

With the demonstration of an effect of GBV-C infection on the outcome of HIV infection, it has become important to understand the epidemiology of GBV-C. The purpose of this study was to determine the prevalence in high- and low-risk populations. The following populations were tested: school children, 9 and 15 years of age (n = 901), blood donors (n = 5,203), hospital employees (n = 1,432), and prisoners and injecting drug users (n = 447). In-house RT-PCR for GBV-CRNA was used together with a commercial ELISA for anti-E2 (Boehringer, Germany). In addition, questionnaires for risk factors for transmission and serological tests for HIV and hepatitis were applied. The overall prevalence of GBV-CRNA was 1.4% among children, 2.2% among blood donors, 2.2% among hospital employees, 12.5% among non-injecting prisoners, and 34.9% among drug injectors. Correspondingly anti-E2 was found in 0.3%, 12.3%, 25.0%, and 42.7%. Among hospital employees, independent risk factors for GBV-C were professions with blood exposure and sexual risk partners. Among prisoners and drug users, injecting and a sexual risk index were associated independently with GBV-C. Based on these results, the following hypothesis is suggested: GBV-C is transmitted frequently at birth or early childhood and this leads to chronic infection in most cases. Sexual transmission is the most important route of transmission in the adult population but this infection is usually transient. Blood borne transmission plays a role among health care workers and injecting drug users and GBV-C should be further evaluated as a surrogate marker for professional blood exposure.

High prevalence of GB virus C/hepatitis G virus RNA among Brazilian blood donors

The aim of this study was to investigate the presence of the Hepatitis G Virus on a population of blood donors from S o Paulo, Brazil and to evaluate its association to sociodemographic variables. Two RT-PCR systems targeting the putative 5'NCR and NS3 regions were employed and the former has shown a higher sensitivity. The observed prevalence of HGV-RNA on 545 blood donors was 9.7% (CI 95% 7.4;12.5). Statistical analysis depicted an association with race/ethnicity, black and mulatto donors being more frequently infected; and also with years of education, less educated donors presenting higher prevalences. No association was observed with other sociodemographic parameters as age, gender, place of birth and of residence. DNA sequencing of nine randomly chosen isolates demonstrated the presence of genotypes 1, 2 and 3 among our population but clustering of these Brazilian isolates was not detected upon phylogenetic analysis.

Interactions Between GB Virus Type C and HIV

GB virus C (GBV-C, also known as hepatitis G virus) commonly causes human infection. Genetically, it is closely related to hepatitis C virus, but GBV-C appears to grow primarily in lymphocytes, not hepatocytes. Although it causes persistent infection in about 25% to 50% of infected individuals, numerous studies have failed to connect GBV-C with any disease process. GBV-C is transmitted sexually, parenterally, and vertically, and due to these shared modes of transmission, coinfection is common among HIV-infected individuals. Of 10 studies done of HIV-GBV-C coinfection, eight found a beneficial effect of GBV-C viremia on HIV-related mortality or response to therapy. The mechanism by which GBV-C may improve survival of HIV-positive people is not known; however, in vitro studies suggest that GBV-C inhibits HIV replication, and preliminary data also point toward alterations in cytokine and/or chemokine expression by GBV-C-infected cells.

High prevalence of GB virus C/hepatitis G virus genotype 3 among autochthonous Venezuelan populations

GB virus C or hepatitis G virus (GBV-C/HGV) is highly prevalent among population groups at risk of parenterally transmitted viral agents, but it has also a worldwide distribution in other non-risk population groups. GBV-C/HGV RNA and antibodies against its envelope protein (anti-E2 Abs) were found in 3/86 (3%) and 7/89 (8%) of biomedical science personnel (BSP), in 31/453 (7%) and 37/200 (19%) of blood donors (BD), and in 6/64 (9%) and 26/59 (44%) of hemodialysis patients (HD) from Caracas, Venezuela. A significant gradient of GBV-C/HGV exposure (anti-E2 Abs and/or GBV-C/HGV RNA) was found between BSP (lowest prevalence), BD, and HD (P < 0.001). GBV-C/HGV RNA and anti-E2 Abs were also found in 2/69 (2.9%) and 2/44 (4.5%) of individuals from a rural community, in 9/162 (5.5%) and 2/40 (5%) of West Amerindians, and in 14/56 (25%) and 4/53 (7.5%) of South Amerindians. Socioeconomic and cultural factors may have contributed to the relatively high risk of exposure to GBV-C/HGV in BD and Amerindians. Whereas GBV-C/HGV genotypes 1 (n = 1), 2 (n = 6), and 3 (n = 22) were present in Venezuela, only the Asiatic genotype 3 was found infecting Amerindians and rural populations (n = 16). Genotype assignment based on the 5' noncoding region of the GBV- C/HGV genome was corroborated in some isolates by genetic analysis of the E2 region. This report confirms the circulation of the Asiatic genotype of GBV-C/HGV among Amerindians, suggesting an old origin of GBV-C/HGV. This might be associated with the apparently low pathogenesis of this virus.

Detection of GB virus C/hepatitis G virus in semen and saliva of HIV type-1 infected men

OBJECTIVE

To investigate the presence of the genome of GB virus C/hepatitis G virus (GBV-C/HGV) in semen and saliva from HIV-1-infected men.

METHODS

Samples of blood from 33 men seropositive for HIV-1 were tested for the presence of GBV-C/HGV markers of infection, RNA by RT-PCR, and anti-E2 antibodies by ELISA, respectively. The cell-free fractions of seminal fluid and saliva samples of the patients with positive blood samples for GBV-C/HGV RNA or anti-E2 antibodies were then analyzed for the presence of the RNA of this virus. In addition, six semen samples and 11 saliva samples from GBV-C/HGV-negative men were tested.

RESULTS

The GBV-C/HGV RNA tested by RT-PCR was recovered from blood in 11 patients of 33 (33.3%), and the antibodies to E2 envelope protein were detected in six patients (18.2%). Since no patient was positive for both markers, the overall prevalence of GBV-C/HGV infection was 51.5% in the studied population. Four-all belonging to the homosexual risk group-of the 17 men with markers to GBV-C/HGV in blood were found to be positive for GBV-C/HGV RNA in mucosal samples: two of them exhibited genomic RNA in both semen and saliva, and two others were positive for semen only. The absence of inhibitors of the PCR technique was confirmed in all mucosal fractions found negative for GBV-C/HGV RNA, except for one saliva sample and one seminal fluid sample.

CONCLUSION

These results confirm the high prevalence of GBV-C/HGV infection in patients infected with HIV-1 by sexual exposure and the presence of GBV-C/HGV RNA in seminal fluid and saliva of men with markers of this virus in the blood, suggesting that mucosal fluids could be a potential source for the spread of the GBV-C/HGV infection.

Hepatitis C-Z: recent advances

In this review, recently identified hepatitis viruses (hepatitis C, hepatitis D, hepatitis E, hepatitis F, hepatitis G, transfusion transmissible virus) are described, and the implications for paediatric liver disease discussed.

Evidence for probable sexual transmission of the hepatitis g virus

A cross-sectional epidemiology study evaluated the role of sexual activity and sexually transmitted diseases (STDs) in the transmission of hepatitis G virus (HGV/GBV-C) and other hepatitis virus infections in 944 subjects. There was a statistically significant higher prevalence of HGV/GBV-C, hepatitis B virus, and hepatitis C virus exposure in the STD clinic group (i.e., subjects who were currently seeking treatment for an STD) compared with the group who never had received treatment for an STD. In a comparison of the subjects with an STD versus those without an STD, the prevalence of HGV/GBV-C was 11.3% versus 4.9%, on the basis of polymerase chain reaction (PCR) results alone, and 36.6% versus 8.8%, when results of PCR and enzyme-linked immunosorbent assay were combined. Sexual activity and, possibly, the presence of an STD increases the risk of HGB/GBV-C transmission.

Investigation of saliva, faeces, urine or semen samples for the presence of GBV-C RNA

GBV-C/HGV has been demonstrated to be distributed worldwide with a prevalence in blood donors higher than HCV. This distribution in the general population probably requires an effective non-parenteral route of transmission. A previous study was performed to evaluate the presence of GBV-C/HGV in serum. Saliva, faeces and urine samples of 30 patients (15 males and 15 females) and 15 semen samples from patients whose serum gave a GBV-C/HGV RNA positive result were then tested by a sensitive polymerase chain reaction (PCR) test. Five semen supernatant samples (33.3%) tested positive--four of them belonged to HIV positive patients--and two saliva samples contained GBV-C/HGV sequences (6.6%)--one from a HIV-positive patient. An internal control was used to detect PCR nonspecific inhibitors in the samples. The data suggest possible non-parenteral routes of transmission from this virus. Its presence in body fluids other than serum has clinical implications other than possible hepatic damage that remain to be investigated.

Epidemiology and prophylaxis of viral hepatitis: a global perspective

BACKGROUND

Viral hepatitis with various forms of acute and chronic liver disease as potential and ultimately fatal sequelae presents a public health problem worldwide.

METHODS

Recent published reports on the global epidemiology and prophylaxis of viral hepatitis were reviewed.

RESULTS

With the advances in novel technologies, eight distinct types of hepatitis virus have been described: Hepatitis A, B, C, D, E, G, TT and SEN viruses. Hepatitis A and E viruses are transmitted by the fecal-oral route and do not induce a chronic carrier state. Due to major changes in epidemiology of hepatitis A virus their significance is more pronounced in areas of intermediate endemicity. Since the available hepatitis A vaccine is rather expensive, cost-benefit studies should be performed with emphasis on the area under consideration or specialized vulnerable groups. Parenterally transmitted hepatitis B and C viruses are major causes of chronic liver disease, including cirrhosis, hepatocellular carcinoma and end-stage liver failure. Hepatitis D virus is unable to replicate on its own, it requires an established hepatitis B virus infection to be able to replicate. Since its introduction, hepatitis B vaccine has been widely used leading to a significant decrease in HBV infection in countries with universal vaccination. Hepatitis G and TT viruses have been characterized within the latter part of the past decade but their significance as to the causation of human liver disease has yet to be elucidated. Likewise, the precise impact of the most recently described SEN virus isolated from patients with post-transfusion hepatitis awaits further studies.

CONCLUSIONS

In the course of this review, we present the situation and focus on research activities emphasizing epidemiology and prevention of the various forms of viral hepatitis.

A case-control study of transmission routes for GB virus C/hepatitis G virus in Swedish blood donors lacking markers for hepatitis C virus infection

BACKGROUND AND OBJECTIVES

The transmission routes for GB virus-C (GBV-C)/hepatitis G virus (HGV) in blood donors unexposed to hepatitis C virus (HCV) are unknown. We performed a case-control study of risk factors for GBV-C/HGV exposure in blood donors.

MATERIALS AND METHODS

After testing stored sera from 458 HCV-negative blood donors for GBV-C/HGV RNA and GBV-C/HGV E2 antibodies, 66 donors with GBV-C/HGV markers and 125 age- and gender-matched controls were interviewed regarding risk factors for viral transmission.

RESULTS

Exposure to GBV-C/HGV was strongly associated with previous treatment for a sexually transmitted disease (odds ratio [OR] 4.6; 95% confidence interval [CI] 2.2-9.8), with multiple sexual partners (OR 2.9; 95% CI 1.4-5.7) and with a past history of endoscopy (OR 7.0; 95% CI 3.0-16.4).

CONCLUSIONS

In blood donors with GBV-C/HGV markers, sexual contacts and medical procedures appear to be the main transmission routes.

GB virus C/hepatitis G virus (GBV-C/HGV): still looking for a disease

GB Virus C and Hepatitis G Virus (GBV-C/HGV) are positive, single-stranded flaviviruses. GBV-C and HGV are independent isolates of the same virus. Transmission via the blood-borne route is the commonest mode, although vertical and sexual transmission is well documented. GBV-C/HGV is distributed globally; its prevalence in the general population is 10 fold higher in African countries than in non-African countries. High prevalences of GBV-C/HGV have been found in subjects with frequent parenteral exposure and in groups at high risk of exposure to blood and blood products. The clinical significance of human infection with GBV-C/HGV is currently unclear. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Only some 12-15% of chronic Non-A, B, C hepatitis cases are infected with GBV-C/HGV. A direct association with liver pathology is still lacking and it is not yet clear as to whether GBV-C/HGV is indeed a hepatotropic virus. Current evidence suggests that the spectrum of association of GBV-C/HGV infection with extrahepatic diseases ranges from haematalogical diseases, aplastic anaemia, human immunodeficiency virus (HIV)-positive idiopathic thrombocytopenia and thalassemia, through to common variable immune deficiency and cryoglobunemia.

GB virus C/hepatitis G virus (GBV-C/HGV): still looking for a disease

GB Virus C and Hepatitis G Virus (GBV-C/HGV) are positive, single-stranded flaviviruses. GBV-C and HGV are independent isolates of the same virus. Transmission via the blood-borne route is the commonest mode, although vertical and sexual transmission is well documented. GBV-C/HGV is distributed globally; its prevalence in the general population is 10 fold higher in African countries than in non-African countries. High prevalences of GBV-C/HGV have been found in subjects with frequent parenteral exposure and in groups at high risk of exposure to blood and blood products. The clinical significance of human infection with GBV-C/HGV is currently unclear. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Only some 12-15% of chronic Non-A, B, C hepatitis cases are infected with GBV-C/HGV. A direct association with liver pathology is still lacking and it is not yet clear as to whether GBV-C/HGV is indeed a hepatotropic virus. Current evidence suggests that the spectrum of association of GBV-C/HGV infection with extrahepatic diseases ranges from haematalogical diseases, aplastic anaemia, human immunodeficiency virus (HIV)-positive idiopathic thrombocytopenia and thalassemia, through to common variable immune deficiency and cryoglobunemia.

Molecular epidemiology of GB virus C/hepatitis G virus in Athens, Greece

The relevance of GB virus C/hepatitis G virus (GBV-C/HGV) infections in liver pathology remains unclear. To investigate the epidemiology of GBV-C/HGV in Athens, Greece, sera from 512 subjects were screened for present and past markers of GBV-C/HGV infection using a reverse transcription-polymerase chain reaction (RT-PCR) and a serological assay, respectively. GBV-C/HGV RNA was detected in 18/56 (32.1%), 12/42 (28.6%), and 16/55 (29.1%) patients with acute hepatitis B, C, or non-A-E, and in 5/58 (8.6%) and 18/68 (26.5%) patients with chronic hepatitis B or C, respectively, as well as in 50/133 (37.6%) hemodialysis patients and 10/100 (10%) healthy individuals. The data indicated that GBV-C/HGV seroprevalence is age-dependent; thus, GBV-C/HGV RNA and anti-E2 positivity were shown to be associated with younger age [odds ratio 0.98, 95% confidence interval (CI) 0. 97-1.00, P = 0.017] and older age (odds ratio 1.03, 95% CI 1.01-1.05, P = 0.002), respectively. No significant associations were identified between GBV-C/HGV RNA status and alanine aminotransferase (ALT) levels in either hepatitis or hemodialysis patients. Nevertheless, GBV-C/HGV RNA-positive acute non-A-E hepatitis patients were more likely to manifest a more severe clinical form of acute hepatitis (P = 0.024). Phylogenetic analysis of partial 5'-untranslated region sequences isolated from 18 viremic individuals showed that most GBV-C/HGV strains circulating in the greater metropolitan area of Athens belong to the 2a subgroup. A genetically diverse type 2 sequence that may represent a novel subtype within group 2 was also characterized.

Analysis of GB virus C markers in families over three generations

GB virus C (GBV-C) markers were analyzed in two to three generations in three families with documented vertical transmission of GBV-C. None of the maternal grandparents had GBV-C markers, whereas the male spouses had GBV-C envelope 2 antibodies. Evidence was found for intrafamilial transmission but not for GBV-C transmission over three generations.

GBV-C/HGV and HCV infection in mixed cryoglobulinaemia

Recently, a new, suspected hepatotropic virus has been identified. Named GBV-C/HGV, this virus shares with the hepatitis C virus (HCV) routes of transmission and molecular organization. Indeed, a proportion of HCV-infected patients (10-25%) are also carriers of GBV-C/HGV. Since mixed cryoglobulinaemia (MC) is closely associated with HCV infection, the aim of this study was to determine the prevalence of GBV-C/HGV infection in MC patients, and to investigate whether the double infection influenced the clinical and/or laboratory aspects of the disease. 52 patients affected by MC were studied. 100 patients affected by HCV-positive chronic liver disease (CLD) without MC were used as control group. To determine the prevalence of GBV-C/HGV infection in general population, 150 blood donors were studied, as well as 80 patients affected by non-A-E CLD. Among the MC patients, only five (9.6%) were positive for both HCV and GBV-C/HGV infection. No difference was found between patients with and without double infection as regards main clinical and laboratory aspects. Among HCV-positive CLD cases, 27 were positive for double infection. Among blood donors, the prevalence of GBV-C/HGV infection was 8.0%, whereas in cases with cryptogenetic CLD the prevalence was 5.0%. In conclusion, these data show that GBV-C/HGV infection does not play any role in the pathogenesis of MC.

Age-dependent acquisition of hepatitis G virus/GB virus C in a nonrisk population: detection of the virus by antibodies

Until now there have been few seroepidemiological data for hepatitis G virus/GB virus type C (HGV/GBV-C). A four-antigen HGV/GBV-C immunoblot was established to examine 446 serum specimens from healthy individuals without risk factors for parenteral viral transmission. These individuals were divided into seven groups according to age. Seroprevalence rates were low for children and adolescents (5.6%) and increased for the age groups assumed to be the most sexually active (15.3 to 26.8%). Remarkably, none of the 80 individuals who tested positive for HGV/GBV-C antibodies were simultaneously positive for HGV/GBV-C viremia. From our data we conclude that HGV/GBV-C infection is widespread in the general population (16 to 25%). The development of an antibody response is associated with clearance of HGV/GBV-C viremia. Due to the lack of risk factors for HGV/GBV-C infection of blood, other efficient transmission routes must exist. It must be assumed that HGV/GBV-C transmission may be linked to sexual activity.