GB virus C/hepatitis G virus

Genetic diversity of hepatitis viruses in West-African countries from 1996 to 2018

The severity of hepatic pathology and the response to treatment depend on the hepatitis virus genotype in the infected host. The objective of this review was to determine the distribution of hepatitis virus genotypes in West African countries. A systematic review of the literature in PubMed, Google Scholar and Science Direct was performed to identify 52 relevant articles reporting hepatitis A, B, C, D, E and G viruses genotypes. Hepatitis B virus (HBV) genotype E with a prevalence of 90.6% (95%CI: 0.891-0.920) found in this review, is characterized by low genetic diversity. Hepatitis C virus (HCV) genotypes 1 and 2 represented 96.4% of HCV infections in West African countries, while hepatitis delta virus, hepatitis A virus, hepatitis G virus genotypes 1 and HEV genotype 3 were reported in some studies in Ghana and Nigeria. HBV genotype E is characterized by high prevalence, low genetic diversity and wide geographical distribution. Further studies on the clinical implications of HBV genotype E and HCV genotypes 1 and 2 are needed for the development of an effective treatment against this viral hepatitis in West African countries. Surveillance of the distribution of different genotypes is also needed to reduce recombination rates and prevent the emergence of more virulent viral strains.

Evaluation of prevalence and risk factors of hepatitis g virus infection among hemodialysis patients referred to Iranian army hospitals in tehran during 2012-2013

BACKGROUND

GB virus C (GBV-C) or hepatitis G virus (HGV) is a newly discovered and enveloped RNA positive-stranded flavivirus-like particle, which has not yet been proven to have major negative effects on liver.

OBJECTIVES

Increasing the risk of blood-borne infections in hemodialysis patients is a main health care concern in different countries. Therefore, it is important to estimate the prevalence and risk factors of hepatitis G virus infection in Iranian hemodialysis patients to design standard prevention and treatment plans.

PATIENTS AND METHODS

In this multicenter observational or epidemiologic study, 138 patients who underwent hemodialysis in Iranian Army hospitals in Tehran were included. Serum HIV antibody (Ab), HCV antibody and HBS antigen (Ag) were assessed. Demographic data such as gender, age, blood group, cause of renal failure, dialysis onset and duration were collected from medical files. GBV-C/HGV was evaluated by nested reverse transcription polymerase chain reaction (RT-PCR) method. Then, all data were analyzed by SPSS ver. 13.

RESULTS

In total, 81 males and 57 females were included. The mean age of patients was 62.16 ± 14.86 years. Six (4.3%) had positive results for GBV-C/HGV by RT-PCR. Except gender (P = 0.045) and duration of dialysis in a week (P < 0.001), other demographic factors revealed no significant difference (P > 0.05). All patients had negative results for HIV Ab, HCV Ab and HBS Ag.

CONCLUSIONS

Overall, 4.3% of patients had positive results for GBV-C/HGV and all negative for HIV, HCV and HBV. Further studies are needed to elucidate real prevalence, risk factors and characteristics of HGV infection in Iranian hemodialysis patients.

Antigenicity of chimeric and cyclic synthetic peptides based on nonstructural proteins of GBV-C/HGV

In this work, new putative epitopes located in nonstructural proteins of GBV-C/HGV were synthesized using solid-phase chemistry for their use in immunoassays. The antigens were obtained in linear, chimeric and cyclic forms with the main aim of improving the sensitivity of the enzyme immunoassays. Our results showed, on one hand, that the combination of different antigens seems to be necessary to ensure good sensitivity and more specificity and, on the other hand, that cyclic compounds show higher ability to recognize anti-GBV-C/HGV antibodies than its parent peptide. Furthermore, CD and FTIR have been used in conjunction to characterize the conformational changes therein with synthetic constructs that could explain their different antigenicity.

HEV, TTV and GBV-C/HGV markers in patients with acute viral hepatitis

The aim of the present study was to evaluate the prevalence of HEV, TTV and GBV-C/GBV-C/HGV in patients with acute viral hepatitis A, B and non-A-C. We evaluated sera of 94 patients from a sentinel program who had acute hepatitis A (N = 40), B (N = 42) and non-A-C (N = 12); 71 blood donors served as controls. IgM and anti-HEV IgG antibodies were detected by enzyme immunoassay using commercial kits. TTV and GBV-C/HGV were detected by nested PCR; genotyping was done by sequencing and phylogenetic analysis. Anti-HEV IgG was present in 38, 10 and 17% of patients with hepatitis A, B and non-A-C. Four patients with hepatitis A and 1 with non-A-C hepatitis also had anti-HEV IgM detected in serum. TTV was detected in 21% of patients with acute hepatitis and in 31% of donors. GBV-C/HGV was detected in 9% of patients with hepatitis, and in 10% of donors. We found TTV isolates of genotypes 1, 2, 3, and 4 and GBV-C/HGV isolates of genotypes 1 and 2. Mean aminotransferase levels were lower in patients who were TTV or GBV-C/HGV positive. In conclusion, the detection of anti-HEV IgM in some acute hepatitis A cases suggests co-infection with HEV and hepatitis E could be the etiology of a few cases of sporadic non-A-C hepatitis in Salvador, Brazil. TTV genotype 1, 2, 3 and 4 isolates and GBV-C/HGV genotype 1 and 2 strains are frequent in the studied population. TTV and GBV-C/HGV infection does not appear to have a role in the etiology of acute hepatitis.

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.

Co-infections with hepatitis G and TT virus in patients with chronic hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection. Seventy-seven patients with chronic hepatitis C--50 of them treated with interferon (IFN)--and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV.

[The novel non-A, non-E hepatitis viruses and their pathogenic effect]

Molecular techniques have allowed the identification of new viruses in a number of patients with cryptogenic hepatitis. Whether they are clinically inapparent or true hepatitis agents remains unknown for some of them. Latest described viruses include GBV, TTV and SENV. However, based on the limited data available, they do not seem to be contenders for the new hepatitis virus title. However, researchers are looking for a role of these viruses in other chronic and acute human diseases. Only a careful evaluation of the data and the scientific concordance of all the evidence will resolve the question of whether they are only commensal viruses or pose a real pathogenic potential.

Pathogenicity of GB virus C on virus hepatitis and hemodialysis patients

AIM: To determine the pathogenicity of GB virus C (GBV-C) on liver and the effects of its co-infection on the clinical features and prognosis of patients with hepatitis B and C.

METHODS: Cross-sectional study was carried out in 413 patients with acute, chronic hepatitis B or liver cirrhosis, and in 67 hemodialysis patients. A 20-month prospective cohort study was carried out in 95 hepatitis B and 80 hepatitis C patients. A reverse transcriptase nested polymerase chain reaction (RT-nPCR) of the 5’-noncoding region was used to detect circulating GBV-C RNA. Liver function was determined by an automated analyzer for all patients.

RESULTS: The prevalence of GBV-C in the high-risk populations with the virus transmitted via blood was high, ranging from 16.2% to 28.8%. Co-infection with GBV-C in hepatitis B patients did not affect the clinical features of the disease or liver function. The dialysis patients infected with GBV-C alone did not develop functional changes to the liver. Prospective cohort study showed that GBV-C co-infection did not affect the clinical features, prognosis or negative serum conversion rate of chronic hepatitis B and C.

CONCLUSION: The results suggest that GBV-C has no marked pathogenicity on liver, so it may not be a hepatitis virus.

Regulation of CC chemokine receptor 5 in hepatitis G virus infection

INTRODUCTION

Epidemiological data demonstrate an association between hepatitis G virus (HGV) co-infection and improved survival of HIV-positive individuals. However, the mechanism by which HGV affects progression of HIV disease remains unclear. As down-regulation of CC chemokine receptor 5 (CCR5) delays HIV progression, we investigated whether CCR5 expression is altered by exposure of lymphocytes to HGV proteins.

METHODS

A cross-sectional analysis of CCR5 expression was carried out on CD4 and CD8 T lymphocytes of 11 HGV-positive and 12 HGV-negative persons, who were homozygous for the CCR5 wild-type gene. Binding of the HGV E2 protein to CD81 was analysed by flow cytometry. Lymphocytes were stimulated with immobilized HGV E2, anti-CD81 or serum proteins from HGV-infected subjects and changes in CCR5 expression and CC chemokine secretion were determined.

RESULTS

We demonstrate that the HGV envelope protein E2 specifically binds to CD81 on T lymphocytes. This interaction induces a dose-dependent release of RANTES and down-regulation of CCR5 surface expression with concomitant intra-cellular accumulation of CCR5 proteins. This effect of HGV E2 on CCR5 expression was confirmed when lymphocytes were incubated with serum proteins from HGV-infected subjects. Finally, our cross-sectional analysis revealed CCR5 expression to be reduced by 53% and 36% on CD4 and CD8 lymphocytes of HGV-infected subjects, respectively (P < 0.01).

CONCLUSIONS

Our results demonstrate that an interaction of HGV E2 with CD81 leads to increased RANTES secretion and decreased CCR5 surface expression. This mechanism might contribute to the delayed progression of HIV-infection in HGV-coinfected patients.

Lipophilic derivatization of synthetic peptides belonging to NS3 and E2 proteins of GB virus-C (hepatitis G virus) and its effect on the interaction with model lipid membranes

The synthesis by solid-phase methodologies of peptides belonging to structural and non-structural proteins of GB virus C as well as its N-alpha-acylation with myristate and palmitate fatty acids is described. To explore the peptide-lipid interactions we have used liposomes composed of dipalmitoylphosphatidylcholine as model membranes and complementary spectroscopic and calorimetric techniques. Our results show that structural and more clearly the structural lipophilic peptide sequences incorporated into lipid bilayers perturb the packing of lipids and affect their thermotropic properties, more than the non-structural selected sequence. However, the binding of the synthetic sequences to lipid membranes occurred without any restructuration of the peptides.

HCV and HGV infection in Hodgkin's disease

Numerous observations imply that the pathogenesis of malignant lymphomas is multifactorial and that viruses probably play an important etiologic role. Besides Epstein-Barr virus, there might be other viruses among the causes of Hodgkin's disease. A total of 111 randomly selected patients with Hodgkin's disease were included in this study, and hepatitis C and G viruses were tested with polymerase chain reaction. The results were compared to hepatitis C and G virus infection ratios assessed by polymerase chain reaction in the Hungarian blood bank. Hepatitis C virus was diagnosed in 10 (9%) patients, and hepatitis G virus in 9 (8,1%), which is a 12-fold and a 1,5-fold infection rate as compared to that of the Hungarian blood bank, respectively. There was no significant difference between hepatitis positive and negative patients concerning mean age at the time of diagnosis, sex, disease stage, histology type, treatment applied, risk factors in the history of the infection and liver enzymes. Hepatitis C virus positivity in patients with Hodgkin's disease differs significantly from that in blood donors. Based on these results and data in the literature, no definite statement can be made on the etiological role of viruses, but further studies are needed.

Hepatitis G virus in clotting factor concentrates

Blood-borne hepatitis is a well-known complication in patients with bleeding disorders. A recently discovered parentally transmitted virus, hepatitis G [GB virus C (GBV-C)] has an increased prevalence in patients with haemophilia. Clotting factor concentrates derived from pools of human plasma currently undergo viral inactivation techniques known to be effective against hepatitis B, C and HIV; however, the effectiveness of current purification and viral inactivation techniques against newly discovered viruses such as GBV-C is unknown. A total of 37 vials of clotting factor concentrates manufactured in the USA from 1981 to 1995 were tested for the presence of GBV-C virus. All samples that did not undergo a specific viral inactivation step were positive for GBV-C. Viral inactivation techniques that did not uniformly remove GBV-C included vapour heat treatment and dry heat treatments for less than 144 h. All samples treated by pasteurization, solvent detergent or dry heat for 144 h, were negative for the presence of GBV-C.

Prevalence of GB virus C/hepatitis G virus in Hungary

In 1995 a new flavivirus, GB virus C/hepatitis G virus (GBV-C/HGV), was discovered. The aim of this study was to determine the prevalence of the virus in healthy persons and hepatitis patients in Hungary. The sera of 408 healthy persons older than 60 years were tested for the presence of GBV-C/HGV antibodies, and 113 were positive (28%). Eight of the 71 healthy persons younger than 60 years and twenty of the 51 sera (39%) taken from patients suffering from hepatitis of unknown origin proved to be positive for GBV-C/HGV antibodies. Ten of the 124 sera (8%) of healthy persons and 36 of the 247 sera (14.6%) of hepatitis patients proved to be positive for GBV-C/HGV RNA. Eleven PCR products were sequenced, and the sequences were found to be different from each other and from the previously published ones. However, three sequences taken from the same patient at different times were identical. These results show that GBV-C/HGV is present in Hungary and cannot be considered rare.

Using Live Pathogens to Treat Infectious Diseases: A Historical Perspective on the Relationship between Gb Virus C and HIV

Recent reports that co-infection with GB virus C (GBV-C) is associated with a reduced mortality in HIV-infected individuals, a slower progression to AIDS, and lower HIV viral loads, suggest a potential role of GBV-C as therapy for HIV infection. Although not known to cause any human disease, GBV-C was only recently discovered and prospective studies assessing long-term consequences of infection have not been completed. Our understanding of the host-viral interactions between humans and GBV-C is in its infancy. Further research into the intriguing relationship between GBV-C and HIV is needed before intentional inoculation of GBV-C into individuals infected with HIV should proceed. This essay explores the history of the once-popular treatment of paretic tertiary syphilis with the blood-borne pathogen Plasmodium vivax, providing a historical perspective on the current state of affairs between GBV-C and HIV. A brief review of GBV-C biology and human infection is followed by a discussion of the current challenges facing the use of this organism to treat HIV.