GB virus C during the natural course of HIV-1 infection: viremia at diagnosis does not predict mortality

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.

Human pegivirus type 1 infection in Asia-A review of the literature

The human pegivirus type 1 (HPgV-1)-as known as hepatitis G virus and GB virus C-is a common single-stranded RNA flavivirus. Because few studies have demonstrated an association between HPgV-1 infection and disease, screening for HPgV-1 is not performed routinely. Nonetheless, a beneficial impact of HPgV-1 infection on HIV disease progression has been reported in multiple studies. Given the burden of HIV in Asia and the complex interactions between viral co-infections and the host, we provide a comprehensive overview of the existing data from Asia on HPgV-1 infection, including the prevalence and circulating genotypes in all Asian countries with data reported. This review highlights the research conducted thus far and emphasizes the need for additional studies on HPgV-1 across the Asian continent.

Inhibition of HIV-1 infection by human pegivirus type 1-derived peptides is affected by human pegivirus type 1 genotype and HIV-1 coreceptor tropism

OBJECTIVE(S)

Up to 40% of HIV-1 infected individuals are coinfected with human pegivirus type 1 (HPgV-1). The majority of studies, but not all, have reported a beneficial effect of HPgV-1 coinfection on HIV-1 disease progression. So far, the impact of different HPgV-1 genotypes on different HIV-1 subtypes remains unclear.

METHODS

Peptides derived from HPgV-1 envelope protein E2, and representing different viral genotypes, were synthesized using Fmoc/t-Bu-based solid phase peptide synthesis. The inhibitory effect of these peptides on the infection of reporter cell lines was tested using an HIV-1 subtype panel representing clades A (n = 2), AG (n = 2), B (n = 6), C (n = 2), D (n = 2), F (n = 2), G (n = 1), G/H (n = 1), and group O (n = 2).

RESULTS

HIV-1 infection was blocked more efficiently by peptides derived from HPgV-1 GT2 than GT1 (P = 0.05). The HIV-1 subtype did not affect the degree of inhibition by a peptide derived from HPgV-1 GT2. All CXCR4-/dual-tropic isolates (n = 12), but only half (four out of eight) CCR5-tropic viruses were inhibited by this peptide (P = 0.014).

CONCLUSION

Our data indicate that the inhibitory effect of peptides derived from HPgV-1 E2 protein is dependent on the genotype, suggesting that coinfection with HPgV-1 GT1 is less likely to confer a beneficial effect on HIV-1 disease progression than GT2. The preferential suppression of more pathogenic CXCR4-tropic HIV-1 by peptides derived from HPgV-1 GT2 may explain the favorable effect in patients harboring these HIV-1 isolates. Consequently, HPgV-1 genotype and HIV-1 coreceptor tropism are likely determinants for the beneficial effect of HPgV-1 co-infection in HIV-1-infected individuals.

The Impact of Human Pegivirus on CD4 Cell Count in HIV-Positive Persons in Botswana

Background

Human pegiviruses (HPgV)-formerly known as hepatitis G virus or GB virus C (GBV-C)-are common single-stranded RNA viruses that may have a beneficial impact on slowing HIV disease progression. The data on HPgV in resource-limited regions such as Sub-Saharan Africa are scarce. Thus, we conducted the first study of HPgV in Botswana as part of a natural history study of HIV subtype C disease progression.

Methods

Plasma samples from 133 HIV-positive adults were evaluated for HPgV RNA, and the 5'UTR was sequenced to determine the HPgV genotype.

Results

HPgV RNA was detected in 41 (30.8%) individuals. While the presence of HPgV RNA had no impact on baseline HIV viral load, a significant difference in baseline CD4 cell count was observed. HPgV genotypes were determined for 27 individuals and included 5 individuals (18.5%) with genotype 1 and 22 (81.5%) with genotype 5. Baseline CD4 cell counts were significantly higher for persons infected with HPgV genotype 5 compared with genotype 1.

Conclusions

These data suggest that HPgV infection is common among HIV-positive individuals in Botswana and has a significant impact on CD4 cell count. This difference in CD4 cell count based on HPgV genotype suggests that HPgV genotype should be evaluated as a possible predictor of HIV disease progression and highlights the need for additional studies of this virus in resource-limited settings.

Cytokine/chemokine expression associated with Human Pegivirus (HPgV) infection in women with HIV

A beneficial impact of the Human Pegivirus (HPgV)-formerly called GB virus C (GBV-C)-on HIV disease progression has been reported previously. One possible mechanism by which HPgV inhibits HIV replication is an alteration of the cytokine/chemokine milieu. Their expression has not been specifically evaluated in women despite their influence on disease progression and the possibility of gender-based differences in expression. Moreover, the impact of HPgV genotype on cytokine/chemokine expression is unknown. Sera levels of IL-2, IL-4, IL-7, IL-8, IL-10, IL-12p70, IL-13, IFNγ, TNFα, IP-10, MIP-1α, MIP-1β, and TGF-β₁ were quantified in 150 HIV-positive women based on HPgV RNA status. Cytokines/chemokines with detection rates of at least 50% included IL-2, IL-4, IL-8, IL-10, IL-12p70, IFNγ, TNFα, IP-10, MIP-1α, MIP-1β, and TGF-β₁ . Absolute values were significantly higher for HPgV positive compared to HPgV negative women for IL-7, IL-13, IL-12p70, and IFNγ. Absolute values were significantly lower for HPgV positive women for IL-4, IL-8, TGF-β₁ , and IP-10. IFNγ values were higher for HPgV genotype 2 than for genotype 1 (P = 0.036). Further study of cytokine/chemokine regulation by HPgV may ultimately lead to the development of novel therapeutic agents to treat HIV infection and/or the design of vaccine strategies that mimic the "protective" effects of HPgV replication.

Recombination among GB virus C (GBV-C) isolates in the United States

GB virus C (GBV-C) is a non-pathogenic flavivirus that may play a role in modulating HIV disease. Multiple genotypes of GBV-C that have been identified to date that may differentially regulate HIV; however, the number of complete GBV-C sequences published to date is very limited. We sequenced full-length GBV-C genomes from four individuals with HIV/HCV co-infection in the United States. Intergenotypic recombination was evident in two of these individuals. Evaluation of additional full-length GBV-C genomes would facilitate the creation of full-length, replication-competent molecular clones of GBV-C to evaluate the phenotypic diversity of GBV-C genotypes and provide important molecular data on this understudied virus.

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.

GB Virus C (GBV-C) Infection in Hepatitis C Virus (HCV) Seropositive Women with or at Risk for HIV Infection

Background

GB virus C (GBV-C) may have a beneficial impact on HIV disease progression; however, the epidemiologic characteristics of this virus are not well characterized. Behavioral factors and gender may lead to differential rates of GBV-C infection; yet, studies have rarely addressed GBV-C infections in women or racial/ethnic minorities. Therefore, we evaluated GBV-C RNA prevalence and genotype distribution in a large prospective study of high-risk women in the US.

Results

438 hepatitis C virus (HCV) seropositive women, including 306 HIV-infected and 132 HIV-uninfected women, from the HIV Epidemiologic Research Study were evaluated for GBV-C RNA. 347 (79.2%) women were GBV-C RNA negative, while 91 (20.8%) were GBV-C RNA positive. GBV-C positive women were younger than GBV-C negative women. Among 306 HIV-infected women, 70 (22.9%) women were HIV/GBV-C co-infected. Among HIV-infected women, the only significant difference between GBV-negative and GBV-positive women was age (mean 38.4 vs. 35.1 years; p<0.001). Median baseline CD4 cell counts and plasma HIV RNA levels were similar. The GBV-C genotypes were 1 (n = 31; 44.3%), 2 (n = 36; 51.4%), and 3 (n = 3; 4.3%). The distribution of GBV-C genotypes in co-infected women differed significantly by race/ethnicity. However, median CD4 cell counts and log₁₀ HIV RNA levels did not differ by GBV-C genotype. GBV-C incidence was 2.7% over a median follow-up of 2.9 (IQR: 1.5, 4.9) years, while GBV-C clearance was 35.7% over a median follow-up of 2.44 (1.4, 3.5) years. 4 women switched genotypes.

Conclusions

Age, injection drug use, a history of sex for money or drugs, and number of recent male sex partners were associated with GBV-C infection among all women in this analysis. However, CD4 cell count and HIV viral load of HIV/HCV/GBV-C co-infected women were not different although race was associated with GBV-C genotype.

GB Virus C infection in Patients With HIV/Hepatitis C Virus Coinfection: Improvement of the Liver Function in Chronic Hepatitis C

BACKGROUND

Previous studies in patients with hepatitis C virus (HCV)/HIV coinfection have shown that the presence of GBV-C is associated with significantly less compensated and decompensated cirrhosis, and an improvement in cirrhosis-free survival.

OBJECTIVES

This study aimed to describe the effect of GBV-C in patients with chronic hepatitis C and HIV coinfection.

PATIENTS AND METHODS

We retrospectively studied 105 injecting drug users with chronic hepatitis C and HIV coinfection and 72 patients with chronic HCV mono-infections. Plasma samples were tested for GBV-C RNA with primers to the 5'untranslated region gene. HIV and HCV viral load, CD4(+) and CD8(+) cell count, and the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested in all patients.

RESULTS

GBV-C RNA was identified in 34 (32.38%) of the patients with HIV/HCV coinfection, and in 24 (33.33%) of the patients with HCV mono-infection. GBV-C infection was associated with significantly lower ALT and AST levels in patients with chronic hepatitis C and HIV coinfection, but not in those HCV mono-infections. The presence of GBV-C infection was not correlated with CD4(+) and CD8(+) cell count, gender, age, HIV load, HCV load, and HCV genotype.

CONCLUSIONS

This study found that GBV-C infection has a high frequency among injecting drug users with HIV/HCV coinfection and HCV mono-infection in Yunnan, China. In patients with chronic hepatitis C and HIV coinfection, GBV-C RNA was associated with significantly lower ALT and AST levels, suggesting a beneficial effect of GBV-C infection on chronic hepatitis C.

GBV-C viremia and clinical events in advanced HIV infection

GB Virus C (GBV-C) is a non-pathogenic flavivirus, commonly found in HIV infected patients. Studies suggest a survival benefit of GBV-C viremia in HIV infection. Impact of GBV-C viremia was evaluated on clinical outcome in multidrug-resistant HIV. The OPTIMA study enrolled advanced multidrug-resistant HIV patients with a CD4 count ≤300 cells/mm(3). This study included a subset of OPTIMA patients. Primary endpoints included AIDS events or death. GBV-C status was assessed at baseline and last time point on study by real-time PCR. Cox proportional hazards models were used to determine if CD4 count (</>100/mm(3)), treatment assignment, presence or disappearance of GBV-C viremia, GBV-C viral load level and Hepatitis C virus antibody status were associated with outcome. Of 288 patients (98% male, baseline mean age 48 years, HIV viral load 4.67 log10/ml, and CD4 127 cells/mm(3)), 62 (21.5%) had detectable GBV-C viremia. The mortality rate for GBV-C infected subjects was lower, 19/62 (30.7%) versus 87/226 (38.5%), and time to death shorter (HR 0.67, 95% CI 0.41-1.11), but the results were not significantly different. The time to development of AIDS events was not different (HR 0.90, 95% CI 0.52-1.53). Among covariates, only CD4 count (HR 0.28, CI 0.19-0.42) had a significant survival effect. A trend in decreased mortality was seen in GBV-C+ patients with CD4 <100/mm(3) in multivariate analyses. GBV-C co-infection in multidrug-resistant HIV infected patients was associated with a trend in improved survival but not decreased AIDS events. Analysis was limited by cohort size.

Molecular epidemiology of GB type C virus among individuals exposed to hepatitis C virus in Cameroon

GB Virus Type C (GBV-C), a blood-borne flavivirus currently infects about one sixth of the world's population. Its transmission has been reported through parenteral, sexual and vertical routes. Unusually for RNA viruses, it exhibits a high degree of conservation of the polyprotein sequence. The geographical distribution of GBV-C suggests an African origin and a long-term co-evolution in the human population but without any known pathogenicity. The aim of this study was to describe the different sub-types of this virus in Southern Cameroon. We studied the genetic epidemiology of GBV-C among rural populations where many HIV-1 and HCV genotypes have been identified. Plasma samples of 345 subjects with evidence of HCV exposure were tested for GBV-C infection. To detect GBV-C RNA, reverse transcription followed by a nested PCR of 5'UTR were performed. Direct sequencing and phylogenetic studies using PHYLIP, PAUP* and SimPlot were carried out. In total, 31 GBV-C RNA-positive samples were detected giving a prevalence of 9.0% among HCV-exposed individuals. Phylogenetic analysis of the 5'UTR showed two distinct clusters: Genotype 1 and Genotype 2. Twenty-eight isolates (8.0%) clustered with Genotype 1 and 3 (1.0%) with Genotype 2. More than one genotype of GBV-C is prevalent in Cameroon of which GBV-C Genotype 1 is more common, confirming reports in the literature. Studying the near full-length genome sequences of GBV-C isolates from primates in this region may provide clues of viral recombination, evolution and origin.

GB virus C infection is associated with altered lymphocyte subset distribution and reduced T cell activation and proliferation in HIV-infected individuals

GBV-C infection is associated with prolonged survival and with reduced T cell activation in HIV-infected subjects not receiving combination antiretroviral therapy (cART). The relationship between GBV-C and T cell activation in HIV-infected subjects was examined. HIV-infected subjects on cART with non-detectable HIV viral load (VL) or cART naïve subjects were studied. GBV-C VL and HIV VL were determined. Cell surface markers of activation (CD38(+)/HLA-DR(+)), proliferation (Ki-67+), and HIV entry co-receptor expression (CCR5+ and CXCR4+) on total CD4+ and CD8+ T cells, and on naïve, central memory (CM), effector memory (EM), and effector CD4+ and CD8+ subpopulations were measured by flow cytometry. In subjects with suppressed HIV VL, GBV-C was consistently associated with reduced activation in naïve, CM, EM, and effector CD4+ cells. GBV-C was associated with reduced CD4+ and CD8+ T cell surface expression of activation and proliferation markers, independent of HIV VL classification. GBV-C was also associated with higher proportions of naïve CD4+ and CD8+ T cells, and with lower proportions of EM CD4+ and CD8+ T cells. In conclusion, GBV-C infection was associated with reduced activation of CD4+ and CD8+ T cells in both HIV viremic and HIV RNA suppressed patients. Those with GBV-C infection demonstrated an increased proportion of naive T cells and a reduction in T cell activation and proliferation independent of HIV VL classification, including those with suppressed HIV VL on cART. Since HIV pathogenesis is thought to be accelerated by T cell activation, these results may contribute to prolonged survival among HIV infected individuals co-infected with GBV-C. Furthermore, since cART therapy does not reduce T cell activation to levels seen in HIV-uninfected people, GBV-C infection may be beneficial for HIV-related diseases in those effectively treated with anti-HIV therapy.

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.

GB virus C envelope protein E2 inhibits TCR-induced IL-2 production and alters IL-2-signaling pathways

GB virus type C (GBV-C) viremia is associated with reduced CD4+ T cell expansion following IL-2 therapy and with a reduction in T cell activation in HIV-infected individuals. The mechanism(s) by which GBV-C might alter T cell activation or IL-2 signaling have not been studied. In this study, we assess IL-2 release, IL-2R expression, IL-2 signaling, and cell proliferation in tet-off Jurkat cells expressing the GBV-C envelope glycoprotein (E2) following activation through the TCR. TCR activation was induced by incubation in anti-CD3/CD28 Abs. IL-2 release was measured by ELISA, STAT5 phosphorylation was assessed by immunoblot, and IL-2Rα (CD25) expression and cell proliferation were determined by flow cytometry. IL-2 and IL-2Rα steady-state mRNA levels were measured by real-time PCR. GBV-C E2 expression significantly inhibited IL-2 release, CD25 expression, STAT5 phosphorylation, and cellular proliferation in Jurkat cells following activation through the TCR compared with control cell lines. Reducing E2 expression by doxycycline reversed the inhibitory effects observed in the E2-expressing cells. The N-terminal 219 aa of E2 was sufficient to inhibit IL-2 signaling. Addition of purified recombinant GBV-C E2 protein to primary human CD4+ and CD8+ T cells inhibited TCR activation-induced IL-2 release and upregulation of IL-2Rα expression. These data provide evidence that the GBV-C E2 protein may contribute to the block in CD4+ T cell expansion following IL-2 therapy in HIV-infected individuals. Furthermore, the effects of GBV-C on IL-2 and IL-2-signaling pathways may contribute to the reduction in chronic immune activation observed in GBV-C/HIV-coinfected individuals.

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.

Influence of GB virus C on IFN-γ and IL-2 production and CD38 expression in T lymphocytes from chronically HIV-infected and HIV-HCV-co-infected patients

This study was designed to assess the effect of GB virus (GBV)-C on the immune response to human immunodeficiency virus (HIV) in chronically HIV-infected and HIV- hepatitis C virus (HCV)-co-infected patients undergoing antiretroviral therapy. A cohort of 159 HIV-seropositive patients, of whom 52 were HCV-co-infected, was included. Epidemiological data were collected and virological and immunological markers, including the production of interferon gamma (IFN-γ) and interleukin (IL)-2 by CD4, CD8 and Tγδ cells and the expression of the activation marker, CD38, were assessed. A total of 65 patients (40.8%) presented markers of GBV-C infection. The presence of GBV-C did not influence HIV and HCV replication or TCD4 and TCD8 cell counts. Immune responses, defined by IFN-γ and IL-2 production and CD38 expression did not differ among the groups. Our results suggest that neither GBV-C viremia nor the presence of E2 antibodies influence HIV and HCV viral replication or CD4 T cell counts in chronically infected patients. Furthermore, GBV-C did not influence cytokine production or CD38-driven immune activation among these patients. Although our results do not exclude a protective effect of GBV-C in early HIV disease, they demonstrate that this effect may not be present in chronically infected patients, who represent the majority of patients in outpatient clinics.

Characterization of a peptide domain within the GB virus C envelope glycoprotein (E2) that inhibits HIV replication

GB virus C (GBV-C) infection is associated with prolonged survival in HIV-infected cohorts, and GBV-C E2 protein inhibits HIV entry when added to CD4+ T cells. To further characterize E2 effects on HIV replication, stably transfected Jurkat cell lines expressing GBV-C E2 or control sequences were infected with HIV and replication was measured. HIV replication (all 6 isolates studied) was inhibited in all cell lines expressing a region of 17 amino acids of GBV-C E2, but not in cell lines expressing E2 without this region. In contrast, mumps and yellow fever virus replication was not inhibited by E2 protein expression. Synthetic GBV-C E2 17mer peptides did not inhibit HIV replication unless they were fused to a tat-protein-transduction-domain (TAT) for cellular uptake. These data identify the region of GBV-C E2 protein involved in HIV inhibition, and suggest that this GBV-C E2 peptide must gain entry into the cell to inhibit HIV.

Evidence for extensive genotypic diversity and recombination of GB virus C (GBV-C) in Germany

Multiple genotypes of GB virus C (GBV-C)-a non-pathogenic flavivirus-have been identified to date, although they are not uniformly distributed worldwide. It has also been suggested that GBV-C genotype may play a role in modulating HIV disease; however, the prevalence and genotype distribution of GBV-C has not been adequately studied in most countries. Among 408 HIV positive subjects in Germany, 97 (23.8%) had detectable GBV-C RNA. Based on sequencing of the 5' untranslated region (5'-UTR), the GBV-C genotypes were 1 (n=8; 8.2%), 2 (n=81; 83.5%), and 3 (n=2; 2.1%), as well as a unique genotype not previously reported (n=6; 6.2%). Among 17 samples also sequenced in the envelope 2 (E2) region, 14 had concordant genotype results when comparing the 5'-UTR and E2, while evidence of intergenotypic recombination was observed among E2 sequences from 3 individuals. These results suggest that genotypic diversity and viral recombination contribute to the overall genetic variability of GBV-C.

Peptides derived from a distinct region of GB virus C glycoprotein E2 mediate strain-specific HIV-1 entry inhibition

The nonpathogenic human GB virus C (GBV-C), a member of the Flaviviridae, is highly prevalent in individuals with HIV-1 infections or with parenteral and sexual risk factors. Long-term GBV-C viremia has been associated with better survival or improved diagnosis in several epidemiological studies. In a previous study we reported that the E2 glycoprotein of GBV-C interferes with HIV-1 entry in vitro. To address the question what region of the E2 protein is involved in suppression of HIV-1 replication, we performed an E2-derived peptide scanning and determined the HIV-inhibitory activity of each peptide in HIV replication assays. We demonstrate here that peptides representing the N-terminal part of the E2 protein from amino acids (aa) 29 to 72 are able to inhibit efficiently HIV-1 replication in vitro. In particular, the peptides P6-2 (representing the E2-region from aa 45 to 64) and P4762 (aa 37 to 64) showed the highest potency in HIV replication assays performed on TZM-bl cells with 50% inhibitory concentrations between 0.1 and 2 μM. However, primary HIV-1 isolates representing clades A to H showed a high variability in their sensitivity to E2 peptides. Pseudovirus inhibition assays revealed that the sensitivity is determined by the gp120/gp41 envelope proteins. Using HIV-1 BlaM-Vpr-based fusion assays, we demonstrate that the E2-derived peptides prevent HIV-1 binding or fusion, presumably via interaction with the HIV-1 particle. Together, these findings reveal a new mechanism of viral interference, suggesting that the envelope protein E2 of GBV-C target directly HIV-1 particles to avoid entry of these virions.

Prevalence, incidence density, and genotype distribution of GB virus C infection in a cohort of recently HIV-1-infected subjects in Sao Paulo, Brazil

BACKGROUND

The results of previous studies elsewhere have indicated that GB virus C (GBV-C) infection is frequent in patients infected with the human immunodeficiency virus type 1 (HIV-1) due to similar transmission routes of both viruses. The aim of this study was to determine the prevalence, incidence density and genotypic characteristics of GBV-C in this population.

METHODOLOGY/PRINCIPAL FINDINGS

The study population included 233 patients from a cohort primarily comprised of homosexual men recently infected with HIV-1 in São Paulo, Brazil. The presence of GBV-C RNA was determined in plasma samples by reverse transcriptase-nested polymerase chain reaction and quantified by real-time PCR. GBV-C genotypes were determined by direct sequencing. HIV viral load, CD4+ T lymphocyte and CD8+ T lymphocyte count were also tested in all patients. The overall prevalence of GBV-C infection was 0.23 (95% CI: 0.18 to 0.29) in the study group. There was no significant difference between patients with and without GBV-C infection and Glycoprotein E2 antibody presence regarding age, sex, HIV-1 viral load, CD4+ and CD8+T cell counts and treatment with antiretroviral drugs. An inverse correlation was observed between GBV-C and HIV-1 loads at enrollment and after one year. Also, a positive but not significant correlation was observed between GBV-C load and CD4+ T lymphocyte. Phylogenetic analysis of the GBV-C isolates revealed the presence of genotype 1 and genotype 2, these sub classified into subtype 2a and 2b.

CONCLUSION/SIGNIFICANCE

GBV-C infection is common in recently HIV -1 infected patients in Sao Paulo, Brazil and the predominant genotype is 2b. This study provides the first report of the GBV-C prevalence at the time of diagnosis of HIV-1 and the incidence density of GBV-C infection in one year.

Prevalence and distribution of the GBV-C/HGV among HIV-1-infected patients under anti-retroviral therapy

Infection with GB virus C (GBV-C) or hepatitis G virus (HGV) is highly prevalent among HIV/AIDS patients. GBV-C/HGV viremia has not been associated with liver disease and seems to slow HIV disease progression. To study the GBV-C/HGV genotypes prevalence among HIV/AIDS patients and its association with HIV viral load (VL) and CD4+ lymphocyte counts. From February 2003 to February 2004, we analyzed 210 HIV-1-infected subjects who were on anti-retroviral therapy (ART). For 63 of them a PCR-nested to the non-coding 5' (5'NCR) region of the GBV-C/HGV was done, and for 49 a DNA direct sequencing was done. A phylogenetic analysis was performed by PHYLIP program. 63 (30%) of the HIV-1-infected patients were co-infected with GBV-C/HGV. The phylogenetic analysis revealed the following genotypes (and respective relative frequencies): 1 (10%), 2a (41%), 2b (43%), and 3 (6%). Co-infected patients presented lower HIV-1 VL and higher T CD4+ lymphocyte cells counts as compared with patients negative for GBV-C/HGV sequences (log=4.52 vs. 4.71, p=0.036), and T CD4+ lymphocyte counts (cells/mm(3)=322.6 vs. 273.5, p=0.081, respectively). T CD4+ cells counts equal to, or higher than, 200/mm(3) were significantly more common among co-infected patients than among HIV-infected-only patients (p=0.042). The lowest T CD4+ cells counts were associated with genotype 1 and the highest with genotype 2b (p=0.05). The GBV-C/HGV infection prevalence was 30% among HIV-1-infected subjects, and was associated with lower VL and higher CD4+ lymphocyte counts. GBV-C/HGV genotype 2b may be associated with better immunological response.

Prevalence and impact of GBV-C, SEN-V and HBV occult infections in HIV-HCV co-infected patients on HCV therapy

BACKGROUND/AIMS

It has been suggested that, in HIV-HCV co-infected patients, co-infections with other viruses may affect the response to HCV therapy. We aimed to assess the prevalence of GBV-C, SEN-V and occult HBV infections, their impact on HCV and HIV infections and on the response to HCV therapy in HIV-HCV co-infected patients.

METHODS

Three-hundred and sixty eight patients were tested before starting interferon-ribavirin for the presence of occult hepatitis B DNA, GBV-C RNA and SEN-V DNA by using real time PCR. Clinical, immunological, virological, histological characteristics and response to HCV therapy were compared according to the presence or not of each viral co-infection.

RESULTS

HBV DNA, GBV-C RNA and SEN-V DNA were found in 5 (1.4%, CI95%: 0.2-2.4%), 104 (29.9%, CI95%: 25.1-34.7%) and 209 patients (57.9%, CI95%: 52.8-63.0%), respectively. GBV-C positive patients had significantly higher CD4 count at baseline, during and after HCV therapy, even after stratification on antiretroviral treatment. No other significant difference was observed according to the presence or not of GBV-C or SEN-V co-infection, in particular regarding virological responses to HCV combination therapy.

CONCLUSIONS

There is no reason to withhold HCV therapy in HIV infected patients who have access to HAART, because of occult HBV, GBV-C or SEN-V co-infections.

Low frequency of GB virus C viremia in a cohort of HIV-1-infected elite suppressors

The persistence of GB virus C viremia in patients with chronic HIV-1 infection has been associated with increased survival. Elite suppressors are untreated HIV-1-infected patients who maintain viral loads of below 50 copies/ml. This study found that the frequency of GB virus C viremia in elite suppressors and chronically infected patients with progressive disease was not significantly different. Thus, GB virus C does not appear to explain the nonprogressive course seen in this cohort of elite suppressors.

Characterization of a peptide domain within the GB virus C NS5A phosphoprotein that inhibits HIV replication

Background

GBV-C infection is associated with prolonged survival in HIV-infected people and GBV-C inhibits HIV replication in co-infection models. Expression of the GBV-C nonstructural phosphoprotein 5A (NS5A) decreases surface levels of the HIV co-receptor CXCR4, induces the release of SDF-1 and inhibits HIV replication in Jurkat CD4+ T cell lines.

Methodology/Principal Findings

Jurkat cell lines stably expressing NS5A protein and peptides were generated and HIV replication in these cell lines assessed. HIV replication was significantly inhibited in all cell lines expressing NS5A amino acids 152–165. Substitution of an either alanine or glycine for the serine at position 158 (S158A or S158G) resulted in a significant decrease in the HIV inhibitory effect. In contrast, substituting a phosphomimetic amino acid (glutamic acid; S158E) inhibited HIV as well as the parent peptide. HIV inhibition was associated with lower levels of surface expression of the HIV co-receptor CXCR4 and increased release of the CXCR4 ligand, SDF-1 compared to control cells. Incubation of CD4+ T cell lines with synthetic peptides containing amino acids 152–167 or the S158E mutant peptide prior to HIV infection resulted in HIV replication inhibition compared to control peptides.

Conclusions/Significance

Expression of GBV-C NS5A amino acids 152–165 are sufficient to inhibit HIV replication in vitro, and the serine at position 158 appears important for this effect through either phosphorylation or structural changes in this peptide. The addition of synthetic peptides containing 152–167 or the S158E substitution to Jurkat cells resulted in HIV replication inhibition in vitro. These data suggest that GBV-C peptides or a peptide mimetic may offer a novel, cellular-based approach to antiretroviral therapy.

Activation of interferon response genes and of plasmacytoid dendritic cells in HIV-1 positive subjects with GB virus C co-infection

GB virus C (GBV-C) coinfection has a protective role in Human Immunodeficiency Virus (HIV) infection, and increases the duration of suppression of HIV-1 viremia in patients under Highly Active Anti-Retroviral Therapy (HAART). Since innate antiviral response may be involved in the protection, we analyzed the possible role of GBV-C as activator of innate immunity. To this aim, we measured the extent of activation of the interferon (IFN) system and of circulating Dendritic Cells (DC) in vivo, and the ability of GBV-C to activate these functions in vitro. Activation of IFN system and of circulating DC was compared in GBV-positive and -negative HIV-1 co-infected patients with HAART-driven suppression of HIV-1 viremia. Endogenous levels of IFN-gamma and RNA-dependent protein kinase (PKR) mRNA were significantly higher in peripheral blood mononuclear cells (PBMC) from GBV-C-positive when compared to GBV-C-negative patients. IFN-gamma expression was correlated with all the Interferon response genes (IRGs) and with GBV-C viremia. The frequency of circulating plasmacytoid DC (pDC) expressing the CD80 activation marker was increased in GBV-C-positive patients, and was correlated with GBV-C viral load. In vitro experiments indicated that GBV-C is able to induce IFN-gamma expression in PBMC. In addition, in PBMC cultures GBV-C induced an increase of CD80 expression by pDC, that was reduced by antibody to IFN-gamma. Our data indicate that in HIV-positive patients GBV-C coinfection promotes the activation of IFN-gamma and downstream IRG expression, as well as with the activation/maturation of circulating pDC. GBV-C-driven IFN-gamma activation is, at least in part, responsible for the increased maturation of pDC. This crosstalk may suggest a role for GBV-C coinfection in boosting the innate antiviral response to HIV infection.

A Bayesian analysis of doubly censored data using a hierarchical Cox model

Two common statistical problems in pooling survival data from several studies are addressed. The first problem is that the data are doubly censored in that the origin is interval censored and the endpoint event may be right censored. Two approaches to incorporate the uncertainty of interval-censored origins are developed, and then compared with more usual analyses using imputation of a single fixed value for each origin. The second problem is that the data are collected from multiple studies and it is likely that heterogeneity exists among the study populations. A random-effects hierarchical Cox proportional hazards model is therefore used. The scientific problem motivating this work is a pooled survival analysis of data sets from three studies to examine the effect of GB virus type C (GBV-C) coinfection on survival of HIV-infected individuals. The time of HIV infection is the origin and for each subject this time is unknown, but is known to lie later than the last time at which the subject was known to be HIV negative, and earlier than the first time the subject was known to be HIV positive. The use of an approximate Bayesian approach using the partial likelihood as the likelihood is recommended because it more appropriately incorporates the uncertainty of interval-censored HIV infection times.

What you need to know about GB virus C

GB virus C (GBV-C) is a nonpathogenic member of the Flaviviridae family most closely related to hepatitis C virus (HCV). Infection is common in healthy and immunocompromised people and may persist for years. GBV-C infection is associated with improved survival, improved AIDS-free survival, higher CD4(+) T-cell counts, and lower HIV viral loads in HIV-infected people compared with people infected with HIV but not GBV-C. The mechanism of this effect is not yet clear, but GBV-C has been shown to inhibit HIV replication in vitro through increased synthesis and secretion of anti-HIV b-chemokines MIP-1a, MIP-1b, RANTES, SDF-1, and SDF-2 and downregulation of CCR5 receptor expression. GBV-C also inhibits apoptosis of its host cell, similar to HCV. GBV-C E2 protein in serum has also been associated with prolonged survival in HIV infection; recent evidence indicates that GBV-C E2 protein may neutralize HIV infection in vitro.

Expression of GB virus C NS5A protein from genotypes 1, 2, 3 and 5 and a 30 aa NS5A fragment inhibit human immunodeficiency virus type 1 replication in a CD4+ T-lymphocyte cell line

GB virus type C (GBV-C) is a common human flavivirus that has been associated with prolonged survival in HIV-positive individuals in several, though not all, epidemiological studies. There are five distinct GBV-C genotypes that are geographically localized, and it has been speculated that GBV-C genotypic differences may explain variable outcomes observed in different clinical studies. Expression of an 85 aa fragment of the GBV-C NS5A phosphoprotein (genotype 2) in a CD4+ T cell line (Jurkat) resulted in inhibition of HIV replication, mediated in part by decreased surface expression of the HIV coreceptor CXCR4 and upregulation of SDF-1. We expressed the NS5A protein from genotypes 1, 2, 3 and 5 in Jurkat cells, and demonstrated that all genotypes inhibited HIV replication. Further deletion mapping demonstrated that expression of a 30 aa fragment resulted in decreased CXCR4 surface expression, upregulation of SDF-1 and inhibition of HIV replication.

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.

Enhanced and resumed GB virus C replication in HIV-1-infected individuals receiving HAART

In patients co-infected with HIV-1 and GB virus C (GBV-C), the disappearance of GBV-C RNA has been associated with accelerated disease progression. We studied longitudinal GBV-C viral titres in 28 HIV-1/GVB-C co-infected individuals receiving HAART. During HAART, median GBV-C RNA titres increased from 95 to 6000 copies/ml (P < 0.001). In patients interrupting HAART, GBV-C-RNA titres decreased as HIV replication resumed. These findings further support the theory that GBV-C replication could depend on the dynamics of HIV progression.

Clinical Impact of GB Virus C Viremia on Patients with HIV Type 1 Infection in the Era of Highly Active Antiretroviral Therapy

BACKGROUND

The influence of GB virus C (GBV-C) viremia on clinical outcomes of patients with human immunodeficiency virus type 1 (HIV-1) infection remains controversial in the era of highly active antiretroviral therapy (HAART).

METHODS

A prospective observational study was conducted to describe the epidemiology of GBV-C viremia and assess its clinical impact on treatment responses to HAART in 385 HIV-1-infected patients during the period from January 1999 through June 2004.

RESULTS

A total of 59 patients (15.3%) had detectable GBV-C RNA viremia during a median observation of 3.6 years (range, 1.0-7.0 years); 47 patients (12.2%) had GBV-C viremia at enrollment, and 12 (3.1%) acquired GBV-C infection during follow-up. Thirty-two (68.1%) of the 47 patients with baseline GBV-C viremia had persistent GBV-C viremia. Compared with patients with clearance of GBV-C viremia (n=15) and patients without detectable GBV-C viremia (n=326), patients with persistent GBV-C viremia were more likely to be men who have sex with men (81.3% vs. 60.4%; P=.02), tended to have lower baseline plasma HIV RNA load (HIV RNA load > or =5 log(10) copies/mL, 31.3% vs. 49.4%; P=.05), and had a higher proportion of isolated anti-hepatitis B core antibody (37.5% vs. 17.2%; P=.005). There was no statistically significant difference in terms of virologic, immunologic, and clinical responses to HAART; occurrence of hepatic events; and mortality among the 3 groups.

CONCLUSIONS

Persistent GBV-C viremia is significantly associated with male-male sex in HIV-infected patients with advanced immunodeficiency, and persistent GBV-C viremia does not confer short-term benefit in patients receiving HAART.

Effect of early and late GB virus C viraemia on survival of HIV-infected individuals: a meta-analysis

OBJECTIVES

To conduct a meta-analysis to synthesize the evidence regarding the effect of co-infection with GB virus C (GBV-C) on survival of HIV-infected individuals, and to estimate the effect.

METHODS

A Bayesian meta-analysis was conducted to synthesize evidence from eligible studies. Prospective survival studies of HIV-1-infected individuals, with outcome defined as time from baseline to all-cause death, were included and classified by whether GBV-C status was determined in early or late HIV disease. The primary measure was the hazard ratio (HR) of death for HIV-infected individuals with GBV-C infection versus those without GBV-C infection.

RESULTS

Eleven studies from eight publications met the inclusion criteria. For studies with GBV-C status measured 2 years or less after HIV seroconversion (912 subjects), the combined HR was 0.88 [95% credible interval (CI) 0.30, 1.50]. For studies with GBV-C status measured more than 2 years after HIV seroconversion (1294 subjects), the combined HR was 0.41 (95% CI 0.23, 0.69).

CONCLUSIONS

No conclusive evidence was found of an association between survival and GBV-C infection early in HIV disease. However, when GBV-C infection was present later in HIV disease, a significant reduction in the hazard for mortality was observed for those with co-infection. Potential explanations for this difference include a non-proportional benefit of GBV-C over time, possibly related to clearance of GBV-C infection early in HIV disease. The timing of GBV-C infection appears to account for the contradictory results of studies on the effect of GBV-C coinfection on survival of HIV-infected people.

Effect of GB virus C on response to antiretroviral therapy in HIV-infected Brazilians

OBJECTIVES

GB virus C (GBV-C) infection is associated with delayed mortality in HIV-infected people in most, but not all, studies. Previous investigations of the effect of GBV-C viraemia on response to antiretroviral therapy (ART) were inconclusive. To determine the effect of GBV-C on ART, we retrospectively analysed plasma samples taken from patients in a prospective randomized clinical trial of ART in HIV-positive Brazilians.

METHODS

GBV-C viraemia was characterized by testing stored serum samples from 175 participants by reverse transcriptase-polymerase chain reaction (RT-PCR). Subjects were randomized to receive indinavir (n=59), zidovudine and lamivudine (n=58), or zidovudine, lamivudine and indinavir (n=58). The effect of GBV-C viraemia on the average change in HIV viral load and CD4 count following initiation of therapy was evaluated in a multiple regression analysis.

RESULTS

The prevalence of GBV-C viraemia was similar to that observed in previous studies (24%). HIV viral load decreased following ART to a significantly greater extent in patients with GBV-C viraemia (by 0.48 log(10) HIV-1 RNA copies/mL, P=0.009, adjusting for age, ART group, and baseline CD4 count). Although there was no significant difference in change in CD4 count between individuals with and without GBV-C viraemia overall, CD4 counts were higher following 48 weeks of therapy in GBV-C viraemic individuals receiving the least potent ART regimen (zidovudine and lamivudine) compared with those without GBV-C infection.

CONCLUSIONS

GBV-C viraemia is associated with an enhanced reduction of HIV viral load in response to ART. In this study of treatment-naive individuals during 48 weeks of follow up, patients with GBV-C viraemia had reductions in HIV viral load that were approximately 0.5 log copies/mL greater than those found in patients without GBV-C viraemia. This is similar to reductions observed with nucleoside reverse transcriptase inhibitors.

No influence of GB virus C on disease progression in a Danish cohort of HIV-infected men

Presumed apathogenic viruses have been suggested to play a role in HIV infection. In some cohorts of HIVpositive patients, GB virus C (GBVC) has been associated with prolonged survival and time to AIDS. We set out to address whether GBVC infection had any influence on survival in a cohort of 112 homosexual white HIV-1 positive Danish men. Patients were enrolled between 1984 and 1987 and followed for a mean of 6.7 years. Follow-up was censored in May 1996 when the first patient in the cohort received HAART. Plasma samples were screened at baseline using polymerase chain reaction methods for GBVC. Of the 112 patients, 27 (24%) were positive for GBVC. No difference in time to AIDS or death was observed between the GBVCnegative and -positive patients. Furthermore, no difference in CD4+ T cell decline was observed in the first year following blood sampling between the GBVC-positive and -negative groups.

Immunosuppression and GB virus C-RNA detection among HIV-infected patients in Cambodia

In this survey, 213 patients in an antiretroviral treatment programme in Phnom Penh, Cambodia, were tested for GB virus C (GBV-C) RNA before treatment initiation. Most had advanced HIV infection, only 34 having CD4 cell counts > 200 cells/microl. GBV-C-RNA was detected in 35 patients. The proportion with positive GBV-C-RNA decreased dramatically with CD4 cell counts < 100 cells/microl. In multivariate analysis, low CD4 cell counts, tuberculosis, anaemia, and traditional medicine were independently and negatively associated with GBV-C-RNA detection.

Multiple viral infections

Individuals at risk of HIV are concomitantly at risk of acquiring parenterally or sexually transmitted viruses. Multiple hepatitis co-infection (HBV+HCV; HBV+HDV; HBV+HDV+HCV) has not been systematically sought after in the large cohorts of HIV-infected patients, but has been reported in 0.4% to more than 50% of patients. HIV-infected patients with multiple hepatitis have a higher rate of liver-related morbidity and mortality than patients with HIV infection alone or with a single hepatitis co-infection. The degree of immunodepression is an important factor in liver disease progression. Since GBV-C virus is transmitted parenterally or by sexual contact, a high prevalence was found in chronic hepatitis C and in HIV-infected patients. Patients with multiple hepatitis have been excluded from randomised therapeutic trials of viral hepatitis in HIV-infected and HIV-negative patients. Thus, the therapeutic approach is based on the results of a small series and empirically oriented toward the prevailing infection. HIV-infected patients should be tested for hepatitis B, C and D systematically and hepatitis B vaccination should be considered for those with HCV co-infection and absence of HBV markers. Studies are needed to assess treatment strategies.

No association between GB virus C infection and disease progression in HIV-2-infected patients from the French ANRS HIV-2 cohort

Out of 183 HIV-2-infected patients tested in the ANRS CO8 HIV-2 cohort, 69 were exposed to GB virus C (GBV-C), yielding a prevalence of 38% (95% CI 30.7, 45.2). There was no significant difference between the CD4 cell count and HIV-2-RNA plasma viral load in patients exposed and not exposed to GBV-C. After adjusting for age and CD4 cell count, co-infection with GBV-C was not associated with clinical progression (hazard ratio 0.78; 95% CI 0.24-2.56, 16 clinical events).