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

Exploring Viral Interference Using Peptides: Molecular Determinants of HIV-1 Inhibition by a Peptide Derived from Human Pegivirus-1 Envelope Protein E2

Co-infection with the human pegivirus 1 (HPgV-1) often has a beneficial effect on disease progression in HIV-1-infected individuals. Several HPgV-1 proteins and peptides, including a 20-mer peptide (P6-2) derived from the N-terminal region of the HPgV-1 surface protein E2, have been associated with this phenomenon, which is referred to as viral interference. We identified the cysteine residues, the hydrophobic core tetrapeptide, as well as the C-terminal negative charge as key factors for the HIV-1 inhibitory activity of P6-2. Analysis of mutations in P6-2-resistant HIV-1 indicated a binding site for the peptide in the HIV-1 envelope glycoprotein gp120. In fact, P6-2 was shown to bind to soluble gp120, as well as to a peptide presenting the gp120 V3 loop. Furthermore, the HIV-1 inhibitory activity of P6-2 could be revoked by the V3 loop peptide, thus indicating a molecular mechanism that involves interaction of P6-2 with the gp120 V3 loop.

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.

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

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

Sequencing and Phylogenetic Study of Partial NS3 Gene of Iranian GB Virus C/Hepatitis G Virus (HGV) Originated From Hemodialysis Patients in Tehran

BACKGROUND

Hepatitis viruses are one of the most important concerns in the patients on hemodialysis who are at high risk for blood-borne infections. GB virus C (GBV-C)/hepatitis G virus (HGV) is positive-stranded RNA virus with global distribution, which codes structural and nonstructural proteins (such as NS3).

OBJECTIVES

Review on literature about Iranian HGV isolates showed that there was no report on sequencing and phylogenetic characteristics of NS3 gene and therefore, this study attempted to answers these challenges.

MATERIALS AND METHODS

Briefly, steps followed were as follows: preparation of nucleic acids from three Iranian hemodialysis HGV-positive samples and RNA extraction; reverse transcriptase-PCR (RT-PCR) for amplification of NS3 gene and gel electrophoresis; sequencing and analyzing sequencing data; NCBI Registering; blasting and alignment of sequences; and finally constructing the phylogenetic tree.

RESULTS

Nucleotide BLAST results emphasized that most similar sequences to Ir NS3 sequences were those from Europe (Spain, Germany, and the United Kingdom) and the United states and IR sequences were located with five leaves in a branch. In addition, homology of Ir sequences showed96.4% (between IR1 and IR2), 94.9% identity (between IR1 and IR3), and 96.5% identity (between IR2 and IR3).Furthermore, highly variation and significance differences in NS3 between GBC isolates from geographical regions and some little changes in IR sequences were seen. Finally, phylogenetic tree revealed that NS3 genotype of Iranian isolates was probably similar to European countries and USA.

CONCLUSIONS

Overall, results of present study were consistent with the data reported earlier base on 5' NTR in Iranian isolates and revealed genotype IR2 is major genotype in Iranian HGV-positive patient. It means there are higher similarities between Iranian and Europe-USA in HGV NS3 gene.

Longitudinal and cross sectional assessments of health utility in adults with HIV/AIDS: a systematic review and meta-analysis

Background

Utility estimates are important health outcomes for economic evaluation of care and treatment interventions for patients with HIV/AIDS. We conducted a systematic review and meta-analysis of utility measurements to examine the performance of preference-based instruments, estimate health utility of patients with HIV/AIDS by disease stages, and investigate changes in their health utility over the course of antiretroviral treatment.

Methods

We searched PubMed/Medline, Cochrane Database of Systematic Review, NHS Economic Evaluation Database and Web of Science for English-language peer-reviewed papers published during 2000–2013. We selected 49 studies that used 3 direct and 6 indirect preference based instruments to make a total of 218 utility measurements. Random effect models with robust estimation of standard errors and multivariate fractional polynomial regression were used to obtain the pooled estimates of utility and model their trends.

Results

Reliability of direct-preference measures tended to be lower than other types of measures. Utility elicited by two of the indirect preference measures - SF-6D (0.171) and EQ-5D (0.114), and that of Time-Trade off (TTO) (0.151) was significantly different than utility elicited by Standard Gamble (SG). Compared to asymptomatic HIV patients, symptomatic and AIDS patients reported a decrement of 0.025 (p&#×2009;=&#×2009;0.40) and 0.176 (p&#×2009;=&#×2009;0.001) in utility scores, adjusting for method of assessment. In longitudinal studies, the pooled health utility of HIV/AIDS patients significantly decreased in the first 3 months of treatment, and rapidly increased afterwards. Magnitude of change varied depending on the method of assessment and length of antiretroviral treatment.

Conclusion

The study provides an accumulation of evidence on measurement properties of health utility estimates that can help inform the selection of instruments for future studies. The pooled estimates of health utilities and their trends are useful in economic evaluation and policy modelling of HIV/AIDS treatment strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-014-0640-z) contains supplementary material, which is available to authorized users.

What determines health-related quality of life among people living with HIV: an updated review of the literature

BACKGROUND

As infection with the Human Immunodeficiency Virus (HIV) has evolved to a chronic disease, perceived health-related quality of life (HRQoL) is becoming a prominent and important patient-reported outcome measure in HIV care. Literature discusses different factors influencing HRQoL in this population, however, currently no consensus exists about the main determinants. In this review a clear, up-to-date overview of the determinants influencing HRQOL among people living with HIV is provided.

METHODS

All studies published before July 2013 that identified determinants of HRQoL among people living with HIV in high-income countries, were considered in this narrative review. PubMed, Web of Science and The Cochrane Library were consulted using the keywords 'determinants', 'quality of life', 'HIV' and 'AIDS'. To be included, studies should have reported overall health and/or physical/mental health scores on a validated instrument and performed multivariable regression analyses to identify determinants that independently influence perceived HRQoL.

RESULTS

In total, 49 studies were included for further analysis and they used a variety of HRQoL instruments: Medical Outcomes Study Short Form-36 or variants, Medical Outcomes Study-HIV, HIV Cost and Services Utilization Study measure, Multidimensional Quality of Life Questionnaire, HIV targeted quality of life instrument, Functional Assessment of Human Immunodeficiency Virus Infection, HIV Overview of Problems Evaluation System, EuroQol, Fanning Quality of Life scale, Health Index and PROQOL-HIV. In this review, the discussed determinants were thematically divided into socio-demographic, clinical, psychological and behavioural factors. Employment, immunological status, presence of symptoms, depression, social support and adherence to antiretroviral therapy were most frequently and consistently reported to be associated with HRQoL among people living with HIV.

CONCLUSIONS

HRQoL among people living with HIV is influenced by several determinants. These determinants independently, but simultaneously impact perceived HRQoL. Most HRQoL instruments do not capture all key determinants. We recommend that the choice for an instrument should depend on the purpose of the HRQoL assessment.

Role of GB virus C in HIV-1-infected and hepatitis C virus-infected hemophiliac children and adolescents

BACKGROUND

GB Virus C (GBV-C) has been associated with a better prognosis of HIV-1 disease in adults. Little is known about prevalence and interaction between GBV-C, HIV-1, and/or hepatitis C virus (HCV) in hemophiliac children and adolescents.

METHODS

A well-characterized cohort of HIV-1-infected and HIV-1-uninfected hemophiliac children and adolescents followed in the Hemophilia Growth and Development Study (HGDS) were evaluated using quantitative reverse transcription polymerase chain reaction to detect GBV-C RNA in samples from baseline and last follow-up visit.

RESULTS

HIV-1-infected (n = 202) and HIV-1-uninfected (n = 119) patients had a low prevalence of GBV-C infection at baseline (0.9 and 0%), which increased at time of last follow-up visit to 25.2% and 26.3%, respectively. In addition, at the time of the follow-up GBV-C measurement, those GBV-C infected had been followed longer and had higher CD4(+) cell counts and lower HIV-1 viral loads than those GBV-C uninfected. These beneficial effects of GBV-C were no longer significant after controlling for CD4(+) cell count and HIV-1 RNA at baseline. HCV RNA clearance was more common amongst those who were not GBV-C infected than those who became GBV-C viremic.

CONCLUSIONS

This study confirms a positive association of GBV-C with milder course of HIV-1 infection. GBV-C infection was associated with a higher likelihood of persistent HCV 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.

Role of GB virus C in HIV-1-infected and hepatitis C virus-infected hemophiliac children and adolescents

BACKGROUND

GB Virus C (GBV-C) has been associated with a better prognosis of HIV-1 disease in adults. Little is known about prevalence and interaction between GBV-C, HIV-1, and/or hepatitis C virus (HCV) in hemophiliac children and adolescents.

METHODS

A well-characterized cohort of HIV-1-infected and HIV-1-uninfected hemophiliac children and adolescents followed in the Hemophilia Growth and Development Study (HGDS) were evaluated using quantitative reverse transcription polymerase chain reaction to detect GBV-C RNA in samples from baseline and last follow-up visit.

RESULTS

HIV-1-infected (n = 202) and HIV-1-uninfected (n = 119) patients had a low prevalence of GBV-C infection at baseline (0.9 and 0%), which increased at time of last follow-up visit to 25.2% and 26.3%, respectively. In addition, at the time of the follow-up GBV-C measurement, those GBV-C infected had been followed longer and had higher CD4(+) cell counts and lower HIV-1 viral loads than those GBV-C uninfected. These beneficial effects of GBV-C were no longer significant after controlling for CD4(+) cell count and HIV-1 RNA at baseline. HCV RNA clearance was more common amongst those who were not GBV-C infected than those who became GBV-C viremic.

CONCLUSIONS

This study confirms a positive association of GBV-C with milder course of HIV-1 infection. GBV-C infection was associated with a higher likelihood of persistent HCV infection.

Health-related quality of life in a randomized trial of antiretroviral therapy for advanced HIV disease

OBJECTIVE

To assess and compare alternative approaches of measuring preference-based health-related quality of life (HRQoL) in treatment-experienced HIV patients and evaluate their association with health status and clinical variables.

DESIGN

Cross-sectional study.

SETTING

Twenty-eight Veterans Affairs hospitals in the United States, 13 hospitals in Canada, and 8 hospitals in the United Kingdom.

PATIENTS

Three hundred sixty-eight treatment-experienced HIV-infected patients enrolled in the Options in Management with Antiretrovirals randomized trial.

MEASUREMENTS

Baseline sociodemographic and clinical indicators and baseline HRQoL using the Medical Outcome Study HIV Health Survey (MOS-HIV), the EQ-5D, the EQ-5D visual analog scale (EQ-5D VAS), the Health Utilities Index Mark 3 (HUI3), and standard gamble (SG) and time trade-off (TTO) techniques.

RESULTS

The mean (SD) baseline HRQoL scores were as follows: MOS-HIV physical health summary score 41.70 (11.16), MOS-HIV mental health summary score 44.76 (11.38), EQ-5D 0.77 (0.19), HUI3 0.59 (0.32), EQ-5D VAS 65.94 (21.71), SG 0.75 (0.29), and TTO 0.80 (0.31). Correlations between MOS-HIV summary scores and EQ-5D, EQ-5D VAS, and HUI3 ranged from 0.60 to 0.70; the correlation between EQ-5D and HUI3 was 0.73; and the correlation between SG and TTO was 0.43. Preference-based HRQoL scores were related to physical, mental, social, and overall health as measured by MOS-HIV. Concomitant medication use, CD4 cell count, and HIV viral load were related to some instruments' scores.

CONCLUSIONS

On average, preference-based HRQoL for treatment-experienced HIV patients was decreased relative to national norms but also highly variable. Health status and clinical variables were related to HRQoL.

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.

Hepatitis C virus infection and the brain

While HCV was initially believed to uniformly cause liver inflammation with the consequence of liver cirrhosis in most of the infected patients, prospective studies have shown a much lower than expected rate of cirrhosis in patients infected for more than 20 years. However, a new problem associated with hepatitis C virus infection is emerging. This is the development of sometimes disabling fatigue. While many other viruses of the flaviviridae cause encephalitis, the most closely related virus to HCV in humans, the GB Virus C seems not to be associated with fatigue. Thus the mechanism for the development of fatigue in HCV infection seems specific for HCV. Delineating the mechanism will be a first step to develop treatment option for this currently untreatable impairment.