Effect of coinfection with GB virus C on survival among patients with HIV infection

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.

HIV-HBV and HIV-HCV coinfection and liver cancer development

Liver diseases caused by chronic HBV or HCV infection, including cirrhosis and HCC, are emerging as an increasingly important problem faced by millions of HIV-infected patients who are coinfected with HBV or HCV. On one hand, HIV-induced immune suppression enhances the risk of chronic viral hepatitis, increases HBV or HCV load, and may hasten the progression to cirrhosis and liver cancer. On the other hand, significant hepatotoxicity is associated with a number of antiretroviral drugs, further exacerbating liver damage associated with chronic viral hepatitis. The exact risk of HCC in HIV and HBV or HCV coinfected patients remains to be fully assessed. The elucidation of the multiple virus-virus and virus-host interactions that underlie viral hepatocarcinogenesis and potential HIV enhancement awaits the establishment of appropriate in vitro and in vivo model systems. As millions of HIV-infected patients in the developing countries are gaining access to HAART therapy for their HIV infections, endemic HBV and HCV infections and their associated liver diseases will only become more problematic on a global level. To ameliorate the suffering from HBV- and HCV-induced liver cancer in HIV patients, more effective treatment for chronic HBV and HCV infections are needed. The long time frame of viral hepatocarcinogenesis may afford a window of opportunity to develop and improve such treatment.

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.

Beneficial effect of GB virus C co-infection in Human Immunodeficiency Virus type 1-infected individuals

Several reports have documented a better prognosis for HIV-1-infected patients co-infected with GBV-C, while other reports have contradicted such findings with the result that this issue remains controversial. We attempted to clarify the complicated status of the effect of GBV-C co-infection on HIV-1-infected patients. GBV-C RNA was detected in 37 samples in 182 HIV-1-infected patients (20.3%) using RT/nested PCR. Of these, 3 were determined to be GBV-C genotype 1, 12 were genotype 2, and the remaining 22 were genotype 3. The GBV-C viral load quantified by real-time PCR ranged from 7.8x10(3) to 3.3x10(6) copies/ml. Weakly negative correlation was observed between GBV-C viral load and HIV-1 viral load in 19 HAART-naïve patients, indicating that a higher GBV-C viral load is associated with a greater suppression of HIV-1 replication. A previously published in vitro study suggested that GBV-C infection would induce up-regulation of RANTES, leading to suppression of HIV-1 replication. However, in our present study, the blood RANTES level was significantly lower in the GBV-C co-infected group than in the uninfected group (190-9,959 vs. 264-31,038 pg/ml, P=0.004). Our results suggested that a suppression of HIV-1 replication by GBV-C co-infection is not mediated by up-regulated RANTES, and thus call for another as yet unknown factor.

Dichotomous effects of C-C chemokines in HIV-1 pathogenesis

Chemokines play a critical role in shaping innate and adaptive immunity. These molecules also participate in maintaining the immune balance in the body. Apart from their regulatory role, these mediators are involved in several inflammatory and autoimmune diseases including viral infection such as HIV-1/AIDS. Chemokine co-receptor CCR5 and CXCR4 and their ligands significantly contribute to HIV-1 disease progression. C-C chemokines such CCL3, CCL4 and CCL5 have been shown to possess antiviral effects by binding to HIV-1 co-receptors. CCL2, a member of the C-C chemokine family, displays a different feature instead. It is a potential enhancer rather than inhibitor of viral replication, a property exhibited by most of the C-C chemokine members. In addition, the role of CCL2 is well established in forming a Th2 type of response by directing differentiation of Th0 cells towards Th2 type, a unique feature of HIV-1 disease. We propose a hypothesis in which the chemotactic nature of CCL2 drives recruitment of target cells to the site of infection as one of the mechanisms operating in vivo that favours viral replication and eventually a high viral load in infected individuals.

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.

Mother-to-infant transmission of multiple blood-borne viral infections from multi-infected mothers

Infants born from mothers with multiple blood-borne viral infections are at risk of multiple transmissions. Whether the risk of transmission of multiple infections increases with the number of viruses infecting the mother is still unknown. The aim of this study was to describe the risk of mother-to-infant transmission of multiple infections from multi-infected mothers. Sixty-four pregnant women infected by at least two viruses among human immunodeficiency virus-type 1 (HIV-1), hepatitis C virus, TT virus, and GB virus type C, together with their 64 infants, were studied. Maternal blood samples were collected in the third trimester of pregnancy and all infants were prospectively followed for evaluation of transmission within 3 months after birth and two times in the subsequent 24 months. Transmission of single and of dual infection from mothers infected by two viruses was, respectively, 10/40 (25%) and 5/40 (12.5%) and from mothers infected by three viruses 9/20 (45%) and 2/20 (10%). One (25%) infant infected by one virus was born from the four mothers infected by four viruses. Transmission of single or dual infection was not significantly associated with the number of viruses infecting the mother (P = 0.9) in the linear regression analysis. Present study suggests the absence of a synergistic effect from viral interactions toward mother-to-infant transmission of multiple infections and supports the hypothesis that transmission from multi-infected mothers is the result of the specific interaction between each virus and the host. These observations may be of clinical relevance in perinatal counseling.

Conserved determinants for membrane association of nonstructural protein 5A from hepatitis C virus and related viruses

Nonstructural protein 5A (NS5A) is a membrane-associated essential component of the hepatitis C virus (HCV) replication complex. An N-terminal amphipathic alpha helix mediates in-plane membrane association of HCV NS5A and at the same time is likely involved in specific protein-protein interactions required for the assembly of a functional replication complex. The aim of this study was to identify the determinants for membrane association of NS5A from the related GB viruses and pestiviruses. Although primary amino acid sequences differed considerably, putative membrane anchor domains with amphipathic features were predicted in the N-terminal domains of NS5A proteins from these viruses. Confocal laser scanning microscopy, as well as membrane flotation analyses, demonstrated that NS5As from GB virus B (GBV-B), GBV-C, and bovine viral diarrhea virus, the prototype pestivirus, display membrane association characteristics very similar to those of HCV NS5A. The N-terminal 27 to 33 amino acid residues of these NS5A proteins were sufficient for membrane association. Circular dichroism analyses confirmed the capacity of these segments to fold into alpha helices upon association with lipid-like molecules. Despite structural conservation, only very limited exchanges with sequences from related viruses were tolerated in the context of functional HCV RNA replication, suggesting virus-specific interactions of these segments. In conclusion, membrane association of NS5A by an N-terminal amphipathic alpha helix is a feature shared by HCV and related members of the family Flaviviridae. This observation points to conserved roles of the N-terminal amphipathic alpha helices of NS5A in replication complex formation.

Influence of lipidation of GBV-C/HGV NS3 (513-522) and (505-514) peptide sequences on its interaction with mono and bilayers

Two decapeptide fragments of the non-structural hepatitis G NS3 protein (GBV-C/HGV), 513-522 (RGRTGRGRSG) and 505-514 (SAELSMQRRG), as well as their palmitoylated derivatives were synthesized. The physico-chemical properties of the peptides were analyzed in both the absence and presence of the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), the negative 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG) and the positive 1,2-dioeloyl-3-trimethylammonium-propane (DOTAP) lipid monolayers. Based on their high hydrophilic properties, neither parent peptide presented surface activity and their incorporation into lipid monolayers was low. In contrast, their palmitoylated derivatives showed concentration-dependent surface activity and could be inserted into lipid monolayers to varying degrees depending on their sequence. Compression isotherms showed that the presence of palmitoylated peptides in the subphase resulted in a molecular arrangement less condensed than that corresponding to the pure phospholipid. In concordance with the monolayer results, differential scanning calorimetry (DSC) demonstrated that the parent peptides did not have any effect on the thermograms, while the palmitoylated derivatives affected the thermotropic properties of DPPC bilayers.

Effect of primer selection on estimates of GB virus C (GBV-C) prevalence and response to antiretroviral therapy for optimal testing for GBV-C viremia

GB virus C (GBV-C; also called hepatitis G virus) is a common cause of infection associated with prolonged survival among HIV-infected individuals. The prevalences of GBV-C viremia vary widely in different studies, and there has been poor agreement among different laboratories performing GBV-C RNA detection in quality control studies. To determine the optimal method of measuring GBV-C RNA in clinical samples, samples obtained from 939 HIV-infected subjects were studied using reverse transcription (RT)-PCR methods amplifying four separate regions of the GBV-C genome. Primers amplifying the E2 coding region were 100% specific; however, their sensitivity was only 76.6%. In contrast, primers amplifying three additional conserved regions of the GBV-C genome (the 5' nontranslated region and the nonstructural protein-coding regions 3 and 5A) were more sensitive but produced higher rates of false-positive results. Using low-specificity primer sets influenced the significance of association between GBV-C viremia and response to antiretroviral therapy. Using a quantitative GBV-C RNA method, the GBV-C RNA concentration did not correlate with baseline or set point HIV RNA levels; however, a correlation between negative, low, and high GBV-C RNA levels and increasing reduction in HIV RNA following antiretroviral therapy was observed. Subjects with both GBV-C E2 antibody and viremia had significantly lower GBV-C RNA levels than did viremic subjects without E2 antibody. These studies demonstrate that accurate detection of GBV-C RNA by nested RT-PCR requires the use of primers representing multiple genome regions. Analyses based on testing with single primers do not lead to reliable conclusions about the association between GBV-C infection and clinical outcomes.

Postgenomic up-regulation of CCL3L1 expression in HTLV-2-infected persons curtails HIV-1 replication

Leukocytes of persons coinfected with HTLV-2 and HIV-1 secrete chemokines that prevent CCR5-dependent (R5) HIV-1 infection of CD4+ T cells and macrophages, with HTLV-2-induced MIP-1alpha as dominant HIV-1 inhibitory molecule. Two nonallelic genes code for CCL3 and CCL3L1 isoforms of MIP-1alpha, and the population-specific copy number of CCL3L1 exerts a profound effect on HIV-1 susceptibility and disease progression. Here, we demonstrate that CCL3L1 is secreted spontaneously by leukocytes of HTLV-2-infected persons and superinduced when cells of HTLV-2/HIV-1 multiply exposed-uninfected seronegative (MEU) persons were stimulated with HIV-1 Env peptides. The CCL3L1 median copy number in MEU, HTLV-2/HIV-1-coinfected long-term nonprogressors (LTNPs) and HIV-1-monoinfected LTNPs were 1, 2, and 3, respectively. An increased CCL3L1/CCL3 mRNA ratio versus PHA-activated healthy leukocytes was observed in both HIV-1-monoinfected LTNPs and in HTLV-2/HIV-1(MEU) subjects. An additional potential correlate of HTLV-2 infection was a rapid and persistent leukocyte secretion of GM-CSF and IFN-gamma, 2 cytokines endowed with CCR5 down-regulation capacity. This study confirms a crucial protective role of CCL3L1 from both HIV infection and disease progression, highlighting a previously not described functional up-regulation of this chemokine variant in both HIV-positive and -negative persons infected with HTLV-2.

Characterization of an immunodominant antigenic site on GB virus C glycoprotein E2 that is involved in cell binding

GB virus type C (GBV-C) is a human flavivirus that may cause persistent infection, although most infected individuals clear viremia and develop antibodies to the envelope glycoprotein E2. To study GBV-C E2 antigenicity and cell binding, murine anti-E2 monoclonal antibodies (MAbs) were evaluated to topologically map immunogenic sites on GBV-C E2 and for the ability to detect or block recombinant E2 binding to various cell lines. Five competition groups of MAbs were identified. Groups I and II did not compete with each other. Group III competed with both groups I and II. Group IV did not compete with group I, II, or III. One MAb competed with all of the other MAbs, suggesting that the epitopes bound by these MAbs are intimately related. Individually, none of the MAbs competed extensively with polyclonal human convalescent antibody (PcAb); however, combinations of all five MAb groups completely blocked PcAb binding to E2, suggesting that the epitopes bound by these MAbs form a single, immunodominant antigenic site. Only group I and III MAbs detected purified recombinant E2 bound to cells in binding assays. In contrast, group II MAbs neutralized the binding of E2 to cells. Both PcAb and MAbs were conformation dependent, with the exception of one group II MAb (M6). M6 bound to a five-amino-acid sequence on E2 if the peptide included four C-terminal or eight N-terminal residues, suggesting that the GBV-C E2 protein contains a single immunodominant antigenic site which includes a complex epitope that is involved in specific cellular binding.

An 85-aa segment of the GB virus type C NS5A phosphoprotein inhibits HIV-1 replication in CD4+ Jurkat T cells

GB virus type C (GBV-C) is an apparently nonpathogenic virus that replicates in T and B lymphocytes and is a common cause of persistent human infection. Among HIV-1-infected individuals, persistent coinfection with GBV-C is associated with prolonged survival, and infection of blood mononuclear cells or CD4+ T cells with GBV-C and HIV in vitro results in significantly reduced HIV-1 replication. To date, the viral protein(s) that lead to HIV inhibition have not been identified. The GBV-C nonstructural phosphoprotein (NS5A) is predicted to have pleotropic effects on cells, including interactions with the IFN-induced dsRNA-activated protein kinase (PKR). We studied GBV-C NS5A to determine whether it is involved in inhibition of HIV replication. GBV-C NS5A protein from an isolate that was cleared by IFN therapy did not inhibit PKR, whereas NS5A from an isolate that was not cleared by IFN-inhibited PKR function in a yeast genetic system. Both of these GBV-C NS5A proteins were expressed in a CD4+ T cell line (Jurkat), and both induced a potent, dose-dependent inhibition of HIV-1 replication, thus the effect was independent of PKR inhibition. NS5A induced the release of the chemokine SDF-1 and decreased surface expression of the HIV coreceptor CXCR4, potentially explaining the HIV inhibition. Deletion mapping of the NS5A protein found that an 85-aa region between amino acids 152 and 237 inhibits HIV-1 replication. Thus, GBV-C NS5A protein alters the cellular milieu necessary for HIV-1 replication and may provide a previously undescribed therapeutic approach for anti-HIV therapy.

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).

GB virus C and HIV-1 RNA load in single virus and co-infected West African individuals

BACKGROUND

Investigations on the impact of GB virus C (GBV-C) co-infection on HIV disease progression relied essentially on clinical follow-up but not on virologic parameters.

OBJECTIVES

To detect and quantify GBV-C RNA in West African populations co-infected or not with HIV-1 and to correlate the RNA load of HIV-1 and GBV-C in co-replicating patients with different clinical conditions.

METHODS

Three Ghanaian populations (blood donors, pregnant women and HIV-infected patients) were subdivided into six groups according to HIV-1 and clinical status and GBV-C and HIV-1 RNA load was tested by quantitative real time reverse transcriptase-polymerase chain reaction. In one population with HIV-1 disease, CD4+ cell count was also measured.

RESULTS

Prevalence of GBV-C markers in HIV-1-infected groups and HIV-1 non-infected pregnant women were significantly higher than in healthy blood donors. Similar levels and distribution of GBV-C RNA load were found in each population irrespective of HIV-1 status except for a lower GBV-C RNA load in AIDS patients. There was a significant shift of HIV-1 load towards lower value when GBV-C RNA was present and a trend towards an inverse correlation between HIV-1 and GBV-C RNA load. A positive correlation between CD4+ cell count and GBV-C RNA load in symptomatic HIV-1-infected patients was observed.

CONCLUSIONS

The moderate impact of GBV-C on HIV-1 viremia is unlikely to entirely account for a favourable clinical outcome of replicating co-infections.

Resistance to HIV infection

The biological correlates of an effective immune response that could contain or prevent HIV infection remain elusive despite substantial scientific accomplishments in understanding the interactions among the virus, the individual and the community. The observation that some individuals appear to possess resistance to HIV infection or its consequences has generated a host of epidemiologic investigations to identify biological or behavioral characteristics of these individuals. These data might hold the keys to developing appropriate strategies for mimicking the effective responses of those who appear immune. In this paper we review genetic mechanisms including the role of chemokines and their receptors, cytokines, host genetic immune response to HIV infection, local immune response correlating with behavioral variables, co-infection and immune based mechanisms that have been elucidated so far. We offer suggestions for how to use these observations as platforms for future research to further understand natural resistance to HIV infection through cohort studies, population genotype sampling, mathematical modeling of virus-host interactions and behavioral analyses.

Comparison of GB virus C, HIV, and HCV infection markers in hemophiliacs exposed to non-inactivated or inactivated factor concentrates

BACKGROUND

Until the mandatory introduction of viral inactivation techniques of blood plasma products in the early 1980s many recipients of these products were infected with various viral pathogens.

OBJECTIVES

To determine the rate of transmission of GB virus C/hepatitis G virus (GBV-C/HGV) HCV, and HIV through non-virus-inactivated clotting factor concentrates in hemophiliacs, as well as the relation between amount of administered clotting factor and risk for GBV-C/HGV infection.

STUDY DESIGN

In this cross-sectional study, we determined retrospectively the rates of infection markers for GBV-C/HGV, HCV, and HIV in a German cohort of hemophiliacs treated with documented amounts of non-virus-inactivated clotting factor concentrates (group A) and in a second group of hemophiliacs who were treated exclusively with virus-inactivated clotting factor (group B). The presence of anti-virus antibodies was determined by ELISA. Viral RNA was detected by RT-PCR. Markers for viral infections were compared to amounts of administered non-virus-inactivated clotting factor.

RESULTS

Among hemophiliacs treated with documented amounts of non-virus-inactivated clotting factor the prevalence for GBV-C/HGV, HCV, and HIV was 40.3%, 98.6%, and 56.3%, respectively. In contrast to HIV, the rate of GBV-C/HGV infections did not increase with increasing amounts of consumed non-inactivated clotting factor. Even in the subgroup of heavily treated hemophiliacs the rate of GBV-C/HGV infection markers did not exceed 45%.

CONCLUSIONS

The amount of non-virus-inactivated clotting factor is not predictive for the risk of GBV-C/HGV infection in hemophiliacs. Despite repeated parenteral exposure more than 55% of hemophiliacs were not infected with GBV-C/HGV. Our findings indicate a high frequency of host factors preventing parenteral transmission of GBV-C/HGV.

HIV and liver diseases: recent clinical advances

Because the life expectancy of patients infected with HIV has been prolonged, liver diseases have assumed far greater importance as a cause of morbidity and mortality in these patients. Given the shared risks of transmission, patients who have HIV often are coinfected with hepatotrophic viruses such as hepatitis C and hepatitis B. Further, antiretroviral therapy (ART) used by patients who have HIV is often hepatotoxic, contributing to liver damage. With increasing immunosuppression caused by AIDS, patients who have HIV have to deal with these issues and the increased risk of infection with opportunistic viral, fungal, bacterial, and protozoal pathogens. In addition, steatosis and lipodystrophy now are recognized more commonly in patients who have HIV, particularly in the setting of ART. Thus, understanding of liver diseases in the setting of HIV infection becomes an important focus in caring these individuals. There have been numerous advances in the treatment of liver disease in patients who have HIV, particularly in treating viral hepatitis C and B. This article reviews various liver manifestations in patients who have HIV and the recent advances in diagnostic and therapeutic options.

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.

Inhibition of HIV strains by GB virus C in cell culture can be mediated by CD4 and CD8 T-lymphocyte derived soluble factors

OBJECTIVE

A number of studies concerning the pathogenesis of GB virus C (GBV-C) in HIV-infected people suggest a beneficial effect and improved survival for dually infected individuals. However there has remained controversy regarding the clinical relevance of these findings, as some studies have not confirmed these observations. To address the possibility of direct inhibitory mechanisms, we studied the impact of GBV-C on HIV-1 replication in vitro.

METHODS

Peripheral blood mononuclear cells (PBMC) were infected with sera from GBV-C positive individuals or transfected with GBV-C specific RNA and superinfected with HIV. Replication kinetics of HIV were studied by quantification of HIV-p24 release. Induction of soluble antiretroviral factors were monitored with an HIV infection assay and by quantification of chemokine secretion. Changes in chemokine receptor expression were analysed by flow cytometry.

RESULTS

We demonstrate that GBV-C infection of PBMC leads to significant replication inhibition of R5- and X4-HIV isolates representing eight HIV clades. The inhibitory effect is mediated by GBV-C infection and also by expression of GBV-C structural glycoproteins and/or of non-structural proteins NS2/NS3. Upon GBV-C infection CD4 and CD8 T lymphocytes produce soluble HIV-suppression factors. Induction of stromal cell-derived factor (SDF)-1 and subsequent internalization of CXCR4 was not observed.

CONCLUSIONS

CD4 and CD8 T lymphocytes are stimulated by GBV-C to secrete antiretroviral factors, inhibiting R5- and X4-HIV strains. As no induction of SDF-1 and no down-regulation of the respective receptor CXCR4 could be observed, it is likely that additional unidentified factors causing inhibition of X4-HIV strains are induced by GBV-C.

GB virus type C NS5A sequence polymorphisms: association with interferon susceptibility and inhibition of PKR-mediated eIF2alpha phosphorylation

GB virus type C (GBV-C) causes persistent infection in humans, although the mechanism by which the virus avoids clearance by the host is unknown. To determine if amino acid polymorphisms in the GB virus type C (GBV-C) NS5A and E2 proteins alter response to interferon (IFN) therapy, we studied the sequence of GBVC NS5A and E2 obtained from people receiving IFN therapy. In addition, we expressed recombinant GBVC NS5A protein to determine if it interferes with RNA-activated protein kinase (PKR) function in vitro. GBVC NS5A amplified from a person whose virus was cleared by IFN therapy (IFN sensitive) demonstrated unique amino acid changes occurring in the region that aligns with the hepatitis C virus (HCV) IFN sensitivity-determining region (ISDR) compared with NS5A sequences from individuals who did not clear GBV-C (IFN resistant). There were no differences in the E2 sequences obtained from IFN-sensitive and IFN-resistant isolates. Using a yeast genetic system, IFN-resistant NS5A inhibited PKR-mediated phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha) in yeast, whereas IFN-sensitive NS5A did not inhibit PKR function. GBV-C NS5A amino acid polymorphisms appear to be involved in response to IFN therapy, and IFN-resistant GBV-C NS5A inhibited PKR-mediated eIF2alpha phosphorylation in a yeast genetic system, suggesting a mechanism by which GBV-C may evade clearance by naturally occurring host antiviral responses.

SEN virus has an adverse effect on the survival of HIV-positive patients

BACKGROUND

Patients infected with HIV are often coinfected with other viruses.

OBJECTIVE

To investigate the effect of SEN virus (SENV) strains D and H on mortality in HIV-positive patients.

METHODS

A total of 217 HIV-positive patients were analysed retrospectively after first presentation and blood sampling (January 1997 to July 1997) and the effect of coinfection with SENV-D and SENV-H on survival was examined. Analysis periods were the time from blood sampling to the end of follow-up, and the time from diagnosis of HIV infection to the end of study follow-up. SENV-H DNA was measured quantitatively. Prevalences of SENV-D and SENV-H were compared with those in 112 healthy blood donors.

RESULTS

SENV prevalence was significantly higher in HIV-positive patients than in controls (56/217 and 12/112, respectively; P < 0.001). SENV positivity had no influence on survival, but a significant negative influence of SENV-H on survival was observed when SENV-H DNA was > 530 copies/ml, which was the mean SENV-H DNA level found in HIV-negative controls. This adverse effect was found for both studied time periods in a Kaplan-Meier analyses. A multivariate Cox regression analysis, including CD4 cell count, Centers for Disease Control and Prevention stage, age, sex, HIV RNA, highly active antiretroviral therapy and hepatitis C virus status, revealed that a high SENV DNA level was an independent risk factor or indicator for adverse disease outcome.

CONCLUSION

SENV infection is common in HIV-positive patients. High SENV-H DNA levels were predictive for poor survival in HIV-positive patients.

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.

Prevalence of GB virus type C in urban Americans infected with human immunodeficiency virus type 1

GBV-C virus infection has been linked to improved clinical outcome in HIV-1 co-infected individuals. The epidemiology of GBV-C has, thus far, been limited to the gay male, HIV+ population. Here we describe the prevalence of antibodies against GBV-C envelope glycoprotein E2 and GBV-C viremia in an HIV+ inner city population. This study group is predominantly African-American; 41% of the participants are women. The major risk factor for HIV infection is intravenous drug use. Overall, 56% of the study population had evidence of current or past infection with GBV-C. GBV-C exposure was not associated with hepatitis C virus infection. The group of participants, who had GBV-C viremia and anti-E2 antibodies, had high percentage of patients with an undetectable HIV-1 viral load. These data provide increased insight into the prevalence of GBV-C co-infection in the HIV epidemic in this understudied population.

Analysis of Chemokine and Cytokine Expression in Patients with HIV and GB Virus Type C Coinfection

BACKGROUND

Plasma levels of several chemokines and cytokines were evaluated in a cohort of 161 human immunodeficiency virus (HIV)positive patients to shed light on a clinically relevant mechanism that would explain the putative beneficial effect of GB virus type C (GBV-C) coinfection.

METHODS

Markers for GBV-C infection were assessed in plasma samples. The syncitium-inducing (SI) capacity of isolated virus from each patient was determined in MT-2 cells. Plasma cytokine and chemokine levels were quantified with use of a commercial enzyme-linked immunosorbent assay.

RESULTS

GBV-C viremia was found in 44 (27%) of 161 patients, and anti-E2 antibodies were found in 18 (21%) of 87. In contrast to the findings of ex vivo analysis, no statistically significant differences were observed in levels of CCL5, stromal cell-derived factor 1, interleukin-7, and tumor necrosis factor-alpha in plasma of patients with or without GBV-C viremia. Seventy-two (45%) and 89 (55%) of our patients harbored SI and non-SI (NSI) strains, respectively. GBV-C viremia was less prevalent among patients with SI strains (13 [18%] of 72) than among patients with NSI strains (30 [34%] of 89; P = .6). Of interest, coinfected patients with SI strains had significantly higher CD4+ T cell values than did patients who were not coinfected.

CONCLUSIONS

Our results suggest that GBV-C infection does not appear to influence the expression of the cytokines and chemokines analyzed herein in a clinically relevant context. Alternative explanations for the elevated levels of HIV-inhibitory chemokines are needed to explain the putative beneficial effect of GBV-C.

GB virus C infection in children with perinatal human immunodeficiency virus infection

BACKGROUND

GB virus C (GBV-C) infection occurs in 20-40% of human immunodeficiency virus (HIV)-infected adults, and coinfection is associated with improved HIV disease outcome.

METHODS

To determine the prevalence of GBV-C infection in children who were perinatally infected with HIV, we conducted a cross-sectional prevalence survey in a cohort of perinatally infected HIV-positive children selected from a large, multicenter observational protocol. A blood specimen was obtained and tested for GBV-C viremia with the use of a qualitative GBV-C RNA assay and screened for past GBV-C infection with enzyme-linked immunosorbent assay to detect antibodies to the GBV-C envelope protein E2 (E2 Ab).

RESULTS

The 354 children who participated in the substudy were relatively healthy, with a median CD4 of 784 cells/mm and median HIV-1 viral load of 1055 copies/mL. The prevalence of GBV-C viremia was 20 of 353 or 5.7% (95% confidence interval, 3.5-8.6%), and the prevalence of E2 Ab was 12 of 354 or 3.4% (95% confidence interval, 1.8-5.8%). GBV-C viremic patients were older than patients without past GBV-C infection (median age, 12.8 years versus 10.7 years). Median CD4 lymphocyte counts were highest in subjects without GBV-C infection and lowest in those with E2 Ab.

CONCLUSIONS

GBV-C prevalence rates are lower in children with perinatal HIV infection than those reported for HIV-infected adults. With the exception of evidence that GBV-C viremic children had lower rates of Centers for Disease Control and Prevention HIV disease category C disease before GBV-C testing, we did not find evidence of improved HIV disease outcome in coinfected patients, but the number of HIV/GBV-C-coinfected children was small.

A Study to Investigate the Impact of the Initiation of Highly Active Antiretroviral Therapy on the Hepatitis C Virus Viral Load in HIV/HCV-Coinfected Patients

Changes in the hepatitis C virus (HCV) viral load (VL) were assessed in a retrospective study of 50 HIV/HCV-coinfected patients who initiated highly active antiretroviral therapy (HAART). Most patients responded to HAART [during the first 6 months, plasma HIV VL fell by a mean 1.39 log10, becoming undetectable (<400 copies/ml) in 22% and CD4+ T cells increased by a mean of 100 cells/μl], but surprisingly, 27 (54%) showed some rise and 25 (50%) showed a significant increase in the HCV VL. This figure was considered to be a minimum estimate. A majority of the patients showed an increase of less than 1 log10 that was associated with a rapid decrease in the HIV VL, whereas an increase in the HCV VL of greater than 1 log10, noted in eight patients, was associated with a baseline CD4+ cell count of less than 200 cells/μl. The increase in the HCV VL was not associated with hepatitis as determined by raised alanine transferase.

Survival in hepatitis C and HIV co-infection: a cohort study of hospitalized veterans

BACKGROUND & AIMS

Previous studies reported increased morbidity and mortality related to liver disease among human immunodeficiency virus (HIV)-infected patients with hepatitis C co-infection. However, the long-term effect of hepatitis C virus (HCV) co-infection on the mortality of HIV-infected patients remains unclear.

METHODS

By using national Veterans Affairs (VA) databases, we performed a retrospective cohort study of HIV patients hospitalized between October 1991 and September 2000. Mortality rates and hazard rate ratios (HRRs) for mortality were calculated for the entire cohort as well as after excluding patients with pre-existing liver disease, with follow-up through September 2001 after discharge. Multivariable adjustment for differences in demographics, comorbidities, and HIV disease severity was performed. Separate analyses were performed for patients identified during the highly active antiretroviral therapy (HAART) era.

RESULTS

We identified 18,081 patients, of whom 5320 patients had dual HCV/HIV infection and 12,761 patients had HIV monoinfection. The number of deaths per 100 patient-years was 7.33 in the dual infection group and 14.13 in the HIV monoinfection group during 22,054 and 40,655 person-years of follow-up, respectively. The mortality rate ratio between HCV/HIV dual infection and HIV monoinfection was .53. In Cox multiple regression, the dual HCV/HIV infection group had an adjusted HRR for mortality of .55 compared with the HIV monoinfection group (95% CI, .51-.58, P < .0001), after controlling for age, race, sex, year of diagnosis, and HIV disease severity. These findings persisted in several sensitivity analyses. However, in the HAART era, if patients with liver disease at baseline were excluded, the HRR for mortality was .83 (95% CI, .73-.94, P = .003).

CONCLUSIONS

Co-infection with hepatitis C is associated with a significant decrease in the mortality of HIV-infected patients. However, this effect was less pronounced during the HAART era.

GB virus C infection and quality of life in HIV-positive patients

It was recently shown that GBV-C infection is associated with prolonged survival of HIV-infected individuals. The GB virus C is the closest known relative of hepatitis C virus in man. The latter has been associated with significant impairment in quality of life, independent from the associated liver disease. We were thus interested in the impact of GB virus C infection on quality of life in HIV-infected individuals. We retrospectively analyzed a cohort of HIV-positive patients who previously answered the 'HIV-SELT' and the 'EQ-5D' questionnaires assessing quality of life and for whom data on GB virus C RNA status were available. In this study we identified no adverse effect of GB virus C on quality of life, but, in contrast, GB virus C viraemic patients showed better quality of life in all parameters for the scores in comparison to GB virus C-negative HIV-infected patients. HIV-positive patients with a GB virus C infection showed superior quality of life. These data further support the favourable course of HIV disease in GB virus C-positive patients.

Detection of human herpesvirus 7 DNA in peripheral blood reflects mainly CD4+ cell count in patients infected with HIV

The opportunistic behavior and the potential interactions of human herpesvirus 7 (HHV-7) with human immunodeficiency virus (HIV)-1 in HIV-1-infected patients were investigated in comparison with HHV-6, another human roseolovirus. Roseolovirus DNAs were detected and quantified in peripheral blood mononuclear cells (PBMCs) from 198 HIV-seronegative healthy blood donors, 38 HIV-1-infected patients classified as long-term non-progressors, and 99 HIV-1-infected patients classified as progressors. The rate of HHV-7 DNA detection was higher in healthy donors (78%) than in long-term non-progressors (47%; P = 0.0003) or in progressors (52%; P < 0.0001). HHV-7 cell load was higher in healthy donors (median: 212 EqCop/10(6) PBMCs) and in long-term non-progressors (median: 105 EqCop/10(6) PBMCs) than in progressors (median: 48 EqCop/10(6) PBMCs; P < 0.0001 and P = 0.015, respectively). Among progressors, HHV-7 detection was correlated positively with the CD4(+) T-lymphocyte count (P = 0.028). Neither HHV-7 detection rate nor cell load was correlated with the HIV-1 plasma load. As a whole, HHV-6 detection rate and cell load were lower than the HHV-7 counterparts, albeit exhibiting similar differences between healthy donors, long-term non-progressors, and progressors. In conclusion, HHV-7 infection does not appear to be stimulated by HIV-1 infection, nor interact with it. Rather, HHV-7 detection rate and cell load reflect CD4(+) T-lymphocyte count, with higher values in healthy donors and long-term non-progressors than in progressors.

Response to Haart and Gb Virus Type C Coinfection in a Cohort of Antiretroviral-Naive HIV-Infected Individuals

The prognostic role of GB virus type C (GBV-C) viraemia in HIV-infected subjects treated with highly active antiretroviral therapy (HAART) is still undefined, The aim of this analysis is to assess the relationship between GBV-C infection and response to antiretroviral therapy among HIV-infected subjects initiating HAART when antiretroviral-naive.

A prospective, observational study of 400 HIV-infected patients with measurements of GBV-C RNA, hepatitis C virus (HCV) antibodies and HCV RNA determined from plasma stored prior to HAART initiation, Time to virological (achieving HIV RNA ≤500 copies/ml) and immunological success (a CD4+ count increase of ≥200cells/μl), and the time to virological relapse (confirmed HIV RNA >500 copies/ml) were assessed by Kaplan-Meier methods and Cox proportional hazard regression model.

Of the subjects, 117 (29.3%) were GBV-C positive and, overall, 351 (87.8%) patients achieved virological success, After controlling for a number of confounders including HCV RNA, GBV-C viraemic patients experienced a significantly lower risk of HIV rebound than those who were GBV-C negative [relative hazard (RH)=0.56, 95% CI: 0.34–0.93, P=0.03], Conversely, the probability of achieving initial virological success or CD4+ count response after HAART did not differ between GBV-C-negative and -positive subjects, These results suggest that GBV-C coinfection may play a role in determining the rate of HIV rebound possibly by competing with HIV replication after HIV load has been successfully suppressed by HAART.

Modifications in SENV DNA Detection and/or SENV Subtype Determination over a Prospective Follow-Up in a Cohort of HIV-Positive Patients: Is This a Moving Target?

SEN virus (SENV) is a new family of single-stranded DNA viruses with eight different strains, A-H. The modifications in SENV DNA detection and subtype distribution were studied over a long-term follow-up (48 +/- 32.5 months) in 52 HIV-infected patients. 46% of the patients in the first sample and 34.6% in the second sample were found to have detectable SENV viremia. While the most prevalent variant in the first sample was found to be genotype A (83.3%), the second sample revealed a broader subtype diversification. Several epidemiological and clinical variables were tested in univariate model for clearance of detectable SENV viremia, but none of them reached statistical significance. In conclusion, a high degree of instability of both SENV DNA detection and subtype distribution in a cohort of HIV-infected patients was suggested, which may have important implications for further studies on both SENV epidemiology and its clinical impact.

Evaluation of Three Molecular Biology-Based Assays for the Detection of GB Virus C/Hepatitis G Virus in Clinical Specimens

OBJECTIVE

The present study was performed to evaluate the reliability of three reverse transcription-polymerase chain reaction (RT-PCR) assays, one commercial and two 'homebrew', for GB virus C (GBV-C)/hepatitis G virus (HGV) RNA detection in clinical specimens. We, therefore, investigated the virus prevalence with the method that gave us the best performances.

METHODS

The commercial assay amplified sequences from the viral 5'-untranslated region (5'UTR) and non-structural 3 (NS3) region. The non-commercial assays 1 and 2 were based on different primers for the 5'UTR consensus sequence.

RESULTS

The percentage of overall concordance by the three methods was 91.7%, raising to 93.0% when only the two non-commercial methods were compared. Assay 1 showed low sensitivity (57.1% vs. the commercial assay, 58.8% vs. assay 2), with 100% specificity. The commercial assay gave 18 of 54 (33.3%) 'false-negative' results, concordantly negative by the other assays. The prevalence of GBV-C/HGV RNA among the HIV+ patients was 27.0 and 32.6% in HIV/HCV co-infected patients.

CONCLUSION

These data suggest that assay 2 has higher reliability as compared to the other two methods and may be used for an accurate GBV-C/HGV RNA detection in clinical and epidemiological studies.

GB virus C/hepatitis G virus infection in dialysis patients and kidney transplant recipients in Central Brazil

In order to investigate the prevalence of GB virus C (GBV-C)/hepatitis G virus (HGV) infection in dialysis patients and kidney transplant recipients in Central Brazil and also to analyze the virus genotypes distribution, a total of 123 patients including 98 on hemodialysis, 13 on continuous ambulatory peritoneal dialysis treatment, and 12 who received kidney transplantation were interviewed in one unit of dialysis treatment in Goiania city. Blood samples were collected and serum samples tested for GBV-C/HGV RNA by polymerase chain reaction. Genotypes were determined by restriction fragment length polymorphism (RFLP) analysis. Eighteen samples were GBV-C/HGV RNA-positive, resulting in an overall prevalence of 14.6% (95% CI: 9.2-21.7). A high positivity for GBV-C/HGV RNA was observed in patients who had received kidney transplant (16.7%), followed by those on hemodialysis (15.3%), and peritoneal dialysis (7.7%). RFLP analysis revealed the presence of genotypes 1, 2, and 3 of GBV-C/HGV; more precisely, 9 (50%) samples were found belonging to the 2b subtype, 4 (22%) to the 2a subtype, 3 (17%) to genotype 1, and 2 (11%) to genotype 3. The present data indicate an intermediate prevalence of GBV-C/HGV infection among dialysis patients and kidney transplant recipients in Central Brazil. Genotype 2 (subtype 2b) seems to be the most prevalent GBV-C/HGV genotype in our region.

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.