Human pegivirus-1 (HPgV-1, GBV-C) RNA prevalence and genotype diversity among volunteer blood donors from an intra-hospital hemotherapy service in Southern Brazil.

OBJECTIVE: Human pegivirus (HPgV-1, GBV-C) is classified within the Pegivirus genus of the Flaviviriade family. The natural history of HPgV-1 infection is still unclear, however, the main route of viral transmission seems to be the parenteral one. The detection of HPgV-1 viremia in blood donors without parenteral exposure demonstrates that other routes of HPgV-1 transmission might also exist. The objective of the present study was to evaluate the prevalence of HPgV-1 RNA and circulating genotypes among blood donors from a intra-hospital Hemotherapy Service localized in the Santa Maria city, central part of the Rio Grande do Sul State in the extreme South of Brazil. METHODS: Blood samples were obtained from 373 volunteer blood donors and tested for the presence of HPgV-1 RNA. All positive for RNA samples were submitted to sequencing and phylogenetic analysis. RESULTS: The prevalence of the HPgV-1 RNA was 5.9% (22/373). The performed phylogenetic analysis demonstrated a predominant detection of genotype 2 with its both subgenotype forms (95.5% of all isolates i.e 54.5% belonging to subgenotype 2 A and 40.9% belonging to subgenotype 2B). Only one sequence was classified as genotype 3 (1/22, 4.5%). CONCLUSIONS: Our study demonstrates the circulation pattern and genotypes of HPgV-1 among volunteer blood donors of South Brazil, and adds to the global knowledge of the natural history and possible transmission routes of this viral agent with putative impact on the area of hemotherapy.

Short article: Hepatitis C and G virus coinfection in Punjab, Pakistan: incidence and its correlation analysis with clinical data.

INTRODUCTION: Hepatitis G virus (HGV) infection appears to be common in patients with chronic hepatitis C virus (HCV) infection. The aim of this study was to investigate the prevalence of HCV/HGV in patients with chronic hepatitis C (CHC) in Pakistan and to look for possible associations with various clinical and histopathological changes in HCV/HGV coinfection and HCV infection. PATIENTS AND METHODS: The present study included 136 patients. Clinical, biochemical, virological and histological findings were compared between patients coinfected with HCV/HGV and patients with HCV alone. RESULTS: Of the 136 patients with CHC, 16 (11.76%) were coinfected with HCV/HGV. The mean age of coinfected patients was lower than in patients with HCV alone. HCV/HGV coinfected patients did not show significant differences in sex, clinical presentation, biochemical markers, and liver fibrosis as compared to those with HCV infection. Only the mean values of platelets count, mean corpuscular hemoglobin (MCH), and MCH concentration markers were significantly different in HCV/HGV coinfected patients as compare to patients with HCV alone. CONCLUSION: It was found that 11.76% of patients with CHC in Pakistan were associated with HCV/HGV coinfection. No significant differences were observed in clinical and histological features except for platelets count, MCH, and MCH concentration markers between HCV and HGV coinfected patients in comparison with HCV-infected patients.

[The algorithms of etiologic laboratory diagnostic of parenteral viral hepatitis].

The article considers methods of laboratory diagnostic of parenteral viral hepatitis. The approaches ensuring single-valued differentiation of infected patients are determined. The various methods of evaluation of activity of infection process are presented. The algorithm of complex laboratory analysis concerning presence of parenteral viral hepatitis (B, C, D, G, TT, SEN) was proposed to ensure maximal informative minimum of laboratory analyses permitting fast and single-valued interpretation of received diagnostic data.

A novel T cell evasion mechanism in persistent RNA virus infection.

Hepatitis C virus (HCV) and GB virus type C (GBV-C) are associated with impaired T cell function despite the fact that HCV replicates in hepatocytes and GBV-C in a small proportion of lymphocytes. Recently, we showed that HCV and GBV-C E2-envelope proteins reduce T cell activation via the T cell receptor (TCR) by competing for phosphorylation with a critical kinase in the TCR signaling cascade (Lck). E2 interfered with TCR signaling in E2 expressing cells and in bystander cells. The bystander effect was mediated by virus particles and extracellular microvesicular particles (exosomes). Multiple kinase substrate sites are predicted to reside on viral structural proteins and based on bioinformatic predictions, many RNA virus pathogens may interfere with TCR signaling via a similar mechanism. Identification of T cell inhibitory effects of virus structural proteins may provide novel approaches to enhance the immunogenicity and memory of viral vaccines.

HIV-1 and GBV-C co-infection in Venezuela.

INTRODUCTION: Co-infection with GB virus C (GBV-C) in patients infected with human immunodeficiency virus 1 (HIV-1) has been associated with prolonged survival. The aim of this study was to evaluate the prevalence of GBV-C infection among HIV-1-infected patients in Venezuela, and to determine the effects of the co-infection on the levels of relevant cytokines. METHODOLOGY: Plasma samples were collected from 270 HIV-1-seronegative and 255 HIV-1-seropositive individuals. GBV-C infection was determined by RT-PCR of the NS5 region and genotyped by sequence analysis of the 5´UTR region. HIV-1 strains were characterized by sequence analysis of pol, vif, env, and nef genes. Selected cytokines were evaluated by ELISA. RESULTS: Ninety-seven of 525 (18.5%) plasma samples tested positive for GBV-C RNA. A significantly higher prevalence of GBV-C was found among HIV-1 patients compared to HIV-1-seronegative individuals (67/255, 26% versus 30/270, 11%; p < 0.001). Statistical difference was observed in the viral load between HIV-1+GBV-C+ and HIV-1+GBV-C- (p = 0.014), although no differences in CD4+ cell counts were found between both groups. TNFα concentration was higher in HIV-1+GBV-C- than in HIV-1+GBV-C+ patients (25.9 pg/mL versus 17.3 pg/mL; p = 0.02); RANTES expression levels were more variable in GBV-C co-infected patients and more frequently elevated in HIV-1 mono-infected patients compared to patients co-infected with GBV-C. CONCLUSIONS: The previously observed beneficial effect of co-infection with HIV-1 and GBV-C on disease progression is complex and might be due in part to a change in the cytokine environment. More studies are required to understand the interaction between both viruses.

Human pegivirus RNA is found in multiple blood mononuclear cells in vivo and serum-derived viral RNA-containing particles are infectious in vitro.

Human pegivirus (HPgV; previously called GB virus C/hepatitis G virus) has limited pathogenicity, despite causing persistent infection, and is associated with prolonged survival in human immunodeficiency virus-infected individuals. Although HPgV RNA is found in and produced by T- and B-lymphocytes, the primary permissive cell type(s) are unknown. We quantified HPgV RNA in highly purified CD4(+) and CD8(+) T-cells, including naïve, central memory and effector memory populations, and in B-cells (CD19(+)), NK cells (CD56(+)) and monocytes (CD14(+)) using real-time reverse transcription-PCR. Single-genome sequencing was performed on viruses within individual cell types to estimate genetic diversity among cell populations. HPgV RNA was present in CD4(+) and CD8(+) T-lymphocytes (nine of nine subjects), B-lymphocytes (seven of ten subjects), NK cells and monocytes (both four of five). HPgV RNA levels were higher in naïve (CD45RA(+)) CD4(+) cells than in central memory and effector memory cells (P<0.01). HPgV sequences were highly conserved among subjects (0.117±0.02 substitutions per site; range 0.58-0.14) and within subjects (0.006±0.003 substitutions per site; range 0.006-0.010). The non-synonymous/synonymous substitution ratio was 0.07, suggesting a low selective pressure. Carboxyfluorescein succinimidyl ester (CFSE)-labelled HPgV RNA-containing particles precipitated by a commercial exosome isolation reagent delivered CSFE to uninfected monocytes, NK cells and T- and B-lymphocytes, and HPgV RNA was transferred to PBMCs with evidence of subsequent virus replication. Thus, HPgV RNA-containing serum particles including microvesicles may contribute to delivery of HPgV to PBMCs in vivo, explaining the apparent broad tropism of this persistent human RNA virus.

AIDS alters the commensal plasma virome.

We compared the plasma viromes of HIV-infected subjects with low versus high CD4(+) T cell counts from the United States and Uganda by using deep sequencing and detected HIV, hepatitis C virus, hepatitis B virus, GB virus C, anellovirus, and human endogenous retrovirus (HERV) reads. An increase in the proportion of reads for anelloviruses, a family of highly prevalent and genetically diverse human viruses, was seen in subjects with AIDS from both countries. The proportion of endogenous human retrovirus reads was increased in AIDS subjects from Uganda but not the United States. Progression to AIDS is therefore associated with changes in the plasma concentration of commensal viruses.

HIV-1 fusion is blocked through binding of GB Virus C E2-derived peptides to the HIV-1 gp41 disulfide loop [corrected].

A strategy for antiviral drug discovery is the elucidation and imitation of viral interference mechanisms. HIV-1 patients benefit from a coinfection with GB Virus C (GBV-C), since HIV-positive individuals with long-term GBV-C viraemia show better survival rates than HIV-1 patients without persisting GBV-C. A direct influence of GBV-C on HIV-1 replication has been shown in coinfection experiments. GBV-C is a human non-pathogenic member of the flaviviridae family that can replicate in T and B cells. Therefore, GBV-C shares partly the same ecological niche with HIV-1. In earlier work we have demonstrated that recombinant glycoprotein E2 of GBV-C and peptides derived from the E2 N-terminus interfere with HIV entry. In this study we investigated the underlying mechanism. Performing a virus-cell fusion assay and temperature-arrested HIV-infection kinetics, we provide evidence that the HIV-inhibitory E2 peptides interfere with late HIV-1 entry steps after the engagement of gp120 with CD4 receptor and coreceptor. Binding and competition experiments revealed that the N-terminal E2 peptides bind to the disulfide loop region of HIV-1 transmembrane protein gp41. In conjunction with computational analyses, we identified sequence similarities between the N-termini of GBV-C E2 and the HIV-1 glycoprotein gp120. This similarity appears to enable the GBV-C E2 N-terminus to interact with the HIV-1 gp41 disulfide loop, a crucial domain involved in the gp120-gp41 interface. Furthermore, the results of the present study provide initial proof of concept that peptides targeted to the gp41 disulfide loop are able to inhibit HIV fusion and should inspire the development of this new class of HIV-1 entry inhibitors.

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.

GB virus C infection is associated with a reduced rate of reactivation of latent HIV and protection against activation-induced T-cell death.

BACKGROUND: GB virus C (GBV-C) coinfection is associated with reduced immune activation and a block in CD4(+) T-cell proliferation following interleukin-2 (IL-2) therapy in HIV-infected individuals. We examined peripheral blood mononuclear cells (PBMCs) from HIV-infected subjects with and without GBV-C viraemia to determine if GBV-C correlated with reactivation of latent HIV, T-cell proliferation or T-cell survival following in vitro activation with phytohaemagglutinin A and IL-2 (PHA/IL-2). METHODS: HIV-infected subjects whose HIV viral load was suppressed on combination antiretroviral therapy (cART) for >6 months were studied. PBMCs were cultured with and without PHA/IL-2 and monitored for HIV reactivation, proliferation and survival. GBV-C viraemia and in vitro replication were detected by real-time RT-PCR. HIV reactivation was determined by measuring HIV p24 antigen in culture supernatants. Proliferation was measured by counting viable cells and survival measured by flow cytometry. RESULTS: Of 49 HIV-infected individuals, 26 had GBV-C viraemia. Significantly less HIV reactivation and PBMC proliferation following in vitro activation with PHA/IL-2 was observed in samples from GBV-C viraemic subjects compared with non-viraemic controls. Following 5 weeks in culture, GBV-C replication was associated with preservation of CD4(+) and CD8(+) T-cells compared with non-viraemic controls. CONCLUSIONS: GBV-C appears to inhibit immune activation and IL-2 signalling pathways, which might contribute to a reduction in reactivation of latent HIV from cellular reservoirs. In addition, GBV-C viraemia was associated with a reduction in activation-induced T-cell death. GBV-C-associated T-cell effects could contribute to the observed protective effect of GBV-C coinfection in HIV-infected individuals.

GB virus C viremia is associated with higher levels of double-negative T cells and lower T-cell activation in HIV-infected individuals receiving antiretroviral therapy.

Double-negative T cells (DNTCs; ie, CD3(+)CD4(-)CD8(-) T cells) play a role in limiting chronic immune activation. GB virus C (GBV-C) infection is associated with reduced T-cell activation in human immunodeficiency virus (HIV)-infected individuals. T-cell activation and DNTCs were measured in HIV-infected subjects with a nondetectable HIV load. GBV-C-viremic subjects had significantly reduced CD4(+) and CD8(+) T-cell activation (P = .003 and .034, respectively) and significantly increased DNTCs (P = .038), compared with nonviremic subjects. GBV-C load correlated with DNTC percentage (P = .004). Thus, GBV-C infection is associated with an increase in DNTCs, which may contribute to reduced immune activation during HIV infection.

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.

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

BACKGROUND: GB virus C (GBV-C) infection is transmitted by blood exposure and associated with lower human immunodeficiency virus (HIV) load and slower HIV disease progression. Few studies describe predictors of acute GBV-C infection following transfusion in HIV-infected patients. METHODS: We used a limited-access database from the National Heart Lung and Blood Institute's Viral Activation Transfusion Study, a randomized controlled trial of leukoreduced versus nonleukoreduced transfusions received by HIV-infected, transfusion-naive patients. Blood samples from 489 subjects were tested for GBV-C markers in pretransfusion and posttransfusion samples. We estimated the risk of acquiring GBV-C RNA and predictors of GBV-C acquisition, using pooled logistic regression. RESULTS: GBV-C RNA was detected ≤120 days following the first transfusion in 22 (7.5%) of 294 subjects who were GBV-C negative before transfusion. The risk of GBV-C RNA acquisition increased with each unit transfused (odds ratio, 1.09; 95% confidence interval, 1.06-1.11). Lower baseline HIV load and use of antiretroviral therapy were associated with subsequent GBV-C RNA acquisition, after control for units of blood transfused. Leukoreduced status of transfused units was not associated with GBV-C transmission. CONCLUSIONS: Blood transfusion is associated with a significant risk of GBV-C acquisition among HIV-infected patients. Transmission of GBV-C by blood transfusion was inversely related to HIV load.

A novel genotype of GB virus C: its identification and predominance among injecting drug users in Yunnan, China.

GB virus C (GBV-C) is prevalent globally and particularly among individuals at risk of parental exposures. Based on genetic diversity, this virus is now classified into six genotypes and many subtypes with distinct geographical distribution. In this study, 120 Injecting Drug Users (IDUs) were recruited from Yunnan province, China. Among them, 43 (35.8%) were positive for GBV-C RNA, 70 (58.3%) and 103 (85.8%) sero-positive for HIV-1 and HCV respectively. This revealed 18.3% of IDUs having GBV-C/HIV/HCV triple infection, which is significantly higher than 7.5% of GBV-C/HIV-1 and 10% of GBV-C/HCV dual infection rates (P<0.05). Based on 5'UTR sequences, the identified 43 viral isolates can be classified into three phylogenetic groups: one (2.3%) and two (4.7%) belonged to genotype 3 and 4, respectively, and the remaining 40 (93%) formed a new group with 97% of bootstrap support. This new GBV-C group was further confirmed by characterizing the E2 region and full-length genome sequences. Analysis of 187 nt 5'UTR sequence showed three previous reported isolates from Southeast Asia were re-classified into this new group. It implies they have the same origin with strains from Yunnan. Although we provisionally assigned this new group as GBV-C genotype 7, a simpler five groups of GBV-C nomenclature is recommended. Genotype 4, 6 and the newly designated genotype 7 could be reclassified as one group, which may represent a single GBV-C genotype. The classification of the other four groups was corresponding to that of previous reported genotype 1, 2, 3 and 5. Furthermore, the diversity of amino acid sequence in the E2 region was analyzed. The inhibitory effect of GBV-C genotype 7 on HIV-1 cell entry could be deduced. Since GBV-C may have a beneficial effect on AIDS disease progression and interact with HCV during co-infection, this finding may raise interests in future studies on this virus that was previously thought to be a "non-pathogenic virus".

Epidemiology and transmission of hepatitis G virus infection in dialysis patients.

Hepatitis G virus (HGV) or GB-virus type C (GBV-C) is distributed globally and is present in the volunteer blood donor population. For epidemiological studies, HGV is of interest in hemodialysis patients who are at risk of parenterally transmitted infections. The role of HGV in producing illness and hepatic disease has yet to be determined. A review of literature was performed in 2009 to summarize scientific reports on epidemiology and pathogenesis of the HGV infection and its exposure through hemodialysis.

GBV-C/hepatitis G virus infection and non-Hodgkin lymphoma: a case control study.

We investigated whether there was an association between GBV-C viremia and the development of non-Hodgkin lymphoma (NHL) in 553 NHL cases and 438 controls from British Columbia, Canada. Cases were aged 20-79, diagnosed between March 2000 and February 2004, and resident in Greater Vancouver or Victoria. Cases and controls were tested for GBV-C RNA by RT-PCR and positive samples were genotyped. Overall, GBV-C RNA was detected in 4.5% of NHL cases vs. 1.8% of controls [adjusted odds ratio (OR) = 2.72, 95% confidence interval (CI) = 1.22-6.69]. The association between GBV-C RNA detection and NHL remained even after individuals with a history of prior transfusion, injection drug use and hepatitis C virus sero-positivity were excluded. GBV-C viremia showed the strongest association with diffuse large B cell lymphoma (adjusted OR = 5.18, 95% CI = 2.06-13.71). Genotyping was performed on 29/33 GBV-C RNA positive individuals; genotypes 2a (n = 22); 2b (n = 5) and 3 (n = 2) were identified, consistent with the distribution of genotypes found in North America. This is the largest case-control study to date associating GBV-C viremia and NHL risk. As GBV-C is known to be transmitted through blood products this may have important implications for blood safety.

Higher risk of cytomegalovirus reactivation in human immunodeficiency virus-1-infected patients homozygous for MICA5.1.

Infection with cytomegalovirus (CMV) induces surface expression of major histocompatibility complex (MHC)-class-I-chain-related A (MICA), a ligand for NKG2D. This leads to improved recognition and elimination of infected cells by natural killer (NK) as well as CD8+ T cells. The MICA5.1 allele codes for a truncated protein. This study was performed to test whether impaired expression of a functional MICA protein would influence the susceptibility to severe CMV reactivation in immunocompromised individuals. In this study, the frequency of MICA5.1 was assessed by polymerase chain reaction in 230 Caucasian human immunodeficiency virus (HIV)-1-infected patients and in 219 healthy controls. Patients co-infected with hepatitis C virus (HCV) and GB virus-C served as controls. MICA5.1 allele was analyzed by polymerase chain reaction. Association of MICA5.1 homozygosity and risk of CMV reactivation was calculated by Pearson chi2 test. Comparison of patients with and without a history of CMV disease manifestation revealed that homozygous MICA5.1 genotype was present in a significantly higher frequency in patients with CMV reactivation (33%) than in those without (16%; p 0.032; odds ratio 0.330). The percentage was similar in HIV-1-infected patients and healthy controls. Furthermore, there was no difference in the frequency of MICA5.1 with respect to infection with HCV and GB virus-C. Our study provides the first in vivo demonstration of an association between homozygous MICA5.1 genotype and susceptibility to CMV reactivation in immunocompromised individuals.

Hepatitis A, B, C, D, E, G: an update.

Acute and chronic liver diseases are an assortment of disorders brought to the clinician's attention by abnormal liver function tests or specific signs and symptoms. The differential diagnosis includes disorders that have primary or secondary liver involvement. This paper will be limited to the epidemiology, clinical manifestations, diagnosis, treatment, and prevention of the different viral liver diseases: A, B, C, D, E and G.

Differential influence of different hepatitis viruses on quality of life in HIV positive patients.

UNLABELLED: HIV-infected individuals are frequently co-infected with different hepatitis viruses. HCV has been associated with impaired quality of life in non-HIV infected patients. Little is known concerning the quality of life in HIV-infected individuals in relation to the different viral co-infections. - PATIENTS AND METHODS: We investigated 250 patients who have answered HIV-SELT and EuroQoL (EQ-5D) questionnaires assessing quality of life. Data on HBsAg, anti-HBc, anti-HCV, and GBV-C-RNA were available for 191, 188, 189, 98 patients, respectively. HCV-RNA was tested in 33 of 35 anti-HCV positive patients. - RESULTS: There was no difference in quality of life in relation to active or past HBV-infection defined by HBsAg (n = 15) and anti-HBc in the absence of HBsAg (n = 84), respectively, for both overall HIV-SELT (p = 0.66, and p = 0.43, respectively) and visual EQ-5D (p = 0.93 and p = 0.64, respectively). However, anti-HCV positivity (n = 35) was associated with significantly impaired quality of life (HIV-SELT overall p<0.001). Importantly, no difference was found in relation to HCV-viraemia in anti-HCV positive patients (p = 0.77). In multivariate analysis anti-HCV positivity, employment status, HIV viral load and GBV-C were relevant to quality of life, with GBV-C being beneficial and HCV being negative. - CONCLUSIONS: While HBV seems to play no role concerning quality of live in HIV-infected patients, the flavi-viruses HCV and GBV-C display opposing influence on quality of life. As quality of life was similarly impaired in HCV-viraemic and HCV-non-viraemic anti-HCV positive patients but better in GBV-C viraemic patients, this should be taken into account in the indication case of planned interferon therapy.