Evidence for probable sexual transmission of the hepatitis g virus

Human Pegivirus Type 1: A Common Human Virus That Is Beneficial in Immune-Mediated Disease?

Two groups identified a novel human flavivirus in the mid-1990s. One group named the virus hepatitis G virus (HGV) and the other named it GB Virus type C (GBV-C). Sequence analyses found these two isolates to be the same virus, and subsequent studies found that the virus does not cause hepatitis despite sharing genome organization with hepatitis C virus. Although HGV/GBV-C infection is common and may cause persistent infection in humans, the virus does not appear to directly cause any other known disease state. Thus, the virus was renamed “human pegivirus 1” (HPgV-1) for “persistent G” virus. HPgV-1 is found primarily in lymphocytes and not hepatocytes, and several studies found HPgV-1 infection associated with prolonged survival in people living with HIV. Co-infection of human lymphocytes with HPgV-1 and HIV inhibits HIV replication. Although three viral proteins directly inhibit HIV replication in vitro, the major effects of HPgV-1 leading to reduced HIV-related mortality appear to result from a global reduction in immune activation. HPgV-1 specifically interferes with T cell receptor signaling (TCR) by reducing proximal activation of the lymphocyte specific Src kinase LCK. Although TCR signaling is reduced, T cell activation is not abolished and with sufficient stimulus, T cell functions are enabled. Consequently, HPgV-1 is not associated with immune suppression. The HPgV-1 immunomodulatory effects are associated with beneficial outcomes in other diseases including Ebola virus infection and possibly graft-versus-host-disease following stem cell transplantation. Better understanding of HPgV-1 immune escape and mechanisms of inflammation may identify novel therapies for immune-based diseases.

Clinical and molecular aspects of human pegiviruses in the interaction host and infectious agent

Background

Human pegivirus 1 (HPgV-1) is a Positive-sense single-stranded RNA (+ ssRNA) virus, discovered in 1995 as a Flaviviridae member, and the closest human virus linked to HCV. In comparison to HCV, HPgV-1 seems to be lymphotropic and connected to the viral group that infects T and B lymphocytes. HPgV-1 infection is not persuasively correlated to any known human disease; nevertheless, multiple studies have reported a connection between chronic HPgV-1 infection and improved survival in HPgV-1/HIV co-infected patients with a delayed and favorable impact on HIV infection development. While the process has not been thoroughly clarified, different mechanisms for these observations have been proposed. HPgV-1 is categorized into seven genotypes and various subtypes. Infection with HPgV-1 is relatively common globally. It can be transferred parenterally, sexually, and through vertical ways, and thereby its co-infection with HIV and HCV is common. In most cases, the clearance of HPgV-1 from the body can be achieved by developing E2 antibodies after infection.

Main body

In this review, we thoroughly discuss the current knowledge and recent advances in understanding distinct epidemiological, molecular, and clinical aspects of HPgV-1.

Conclusion

Due to the unique characteristics of the HPgV-1, so advanced research on HPgV-1, particularly in light of HIV co-infection and other diseases, should be conducted to explore the essential mechanisms of HIV clearance and other viruses and thereby suggest novel strategies for viral therapy in the future.

Viral Hepatitis in pregnancy

The global prevalence of viral hepatitis is very high and seems to be rising over the years. The infection can profoundly affect pregnant women causing significant maternal and perinatal morbidity and mortality with some strains much worse than others. Hepatitis A (HAV) and E (HEV) which are transmitted mainly through the faecal-oral route present as acute hepatitis during pregnancy and are responsible for most local epidemic outbreaks. HAV infection remains self-limiting during pregnancy, while HEV has a higher prevalence and causes significant morbidity. It is also associated with a very high maternal mortality rate (20 %) and requires special attention in endemic areas. HEV vaccines do exist, but the WHO has yet to approve them for general use. Hepatitis B is the most prevalent form and is part of the ante-natal screening program. The presence of HBeAg is associated with high viral loads and infectivity. Antiviral therapy, preferably tenofovir (TDF), is recommended for mothers with viral load ≥ 200,000 IU/mL₂), with the neonates receiving both active and passive immunisations. Hepatitis C and D are usually found as chronic infections in the pregnant and non-pregnant populations. Screening for hepatitis C during pregnancy and its subsequent management is still unsettled, but the introduction of direct-acting antiviral (DAA) drugs will change the picture if their safety is established in pregnancy. HDV is an incomplete virus linked to HBV and cannot establish an infection on its own. Controlling HBV is paramount to controlling HDV. HEV is quite prevalent and looked upon as hepatotropic. It seems to be quite prevalent in some blood donor populations and has a high co-infection rate with HCV. It has a high Mother-to-Child-Transmission (MTCT) but causes little or no illness in infected infants, and antenatal screening is not justified. This review summarises the prevalence, clinical picture, maternal, perinatal effects, and the management and prevention of hepatitis A, B, C, D, E and G viral infections during pregnancy.

Human pegivirus-1 (HPgV-1) RNA prevalence and genotypes in volunteer blood donors from the Brazilian Amazon

OBJECTIVES

The objectives of this study were to evaluate the prevalence of Human Pegivirus-1 (HPgV-1) viremia and genotype diversity among healthy blood donors from the Eastern Brazilian Amazon (city of Macapá, State of Amapá). There is little information for prevalence and circulation of HPgV-1 in this remote Brazilian region.

MATERIALS AND METHODS

We conducted a study evaluating the HPgV-1 RNA prevalence and circulating genotypes in 431 volunteer blood donors originating from the Eastern Brazilian Amazon. The obtained HPgV-1 positive samples were submitted to sequencing and genotyping analysis in order to examine the genotype diversity of this virus in the Brazilian Amazon.

RESULTS

Our results demonstrated a prevalence of HPgV-1 RNA in 9.5% of the tested blood donors. The phylogenetic analyses of the detected positive samples showed the presence of HPgV-1 genotypes 1, 2 and 3. The most frequently detected genotype was 2 (78.0% of the cases) represented by sub-genotypes 2A (39.0%) and 2B (39.0%). At lower rates, genotypes 1 (14.6%) and 3 (7.4%) were also detected.

CONCLUSION

Our results revealed the presence of genotypes with European, Asiatic and African endemicity in Amazonian blood donors, probably due to the complex miscegenation processes that took place in this Brazilian region. More investigations, including information for the prevalence of HPgV-1 RNA in blood donors from other Latin American countries are needed to estimate the viremic rates and genotype distribution of this virus in a highly diverse continent like South America.

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

Background

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

Results

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

Conclusions

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

Hepatitis C virus and GBV-C virus prevalence among patients with B-cell lymphoma in different European regions: a case-control study of the International Extranodal Lymphoma Study Group

Hepatitis C virus (HCV) infection is associated with some B-cell non-Hodgkin lymphoma (B cell-NHLs). Patients with HCV infection frequently show co-infections with GB virus C (GBV-C, formerly known as hepatitis G virus), and some studies have suggested a higher incidence of GBV-C infection in patients with B cell-NHLs. The aim of this study was to prospectively evaluate the association between HCV and/or GBV-C infection and B cell-NHLs in different geographic areas. One hundred thirty-seven lymphoma cases and 125 non-lymphoma matched controls were enrolled in an international case-control study conducted in Switzerland (Bellinzona), Spain (Barcelona) and England (Southampton) on samples collected from 2001 to 2002. In Bellinzona (41 cases and 81 controls), the overall prevalence of HCV was 3.3% (4.9% in NHLs), and the overall prevalence of GBV-C was 24% (22% in NHLs). In Barcelona (46 cases and 44 controls), the prevalence of HCV was 10% (8.7% in NHLs) and the prevalence of GBV-C 20% (13% in NHLs). There was no statistically significant difference in the frequency of both infections between patients with NHL and controls. In Southampton, 50 NHL cases were analysed, none of them was found to be HCV-positive; therefore, no control group was analysed and GBV-C analysis was not performed, too. Both in Bellinzona and in Barcelona, the seropositivity rate was significantly lower for HCV than for GBV-C, suggesting that their transmission can be independent. The incidence of HCV was significantly higher in Barcelona than that in Bellinzona. This study confirmed the existence of marked geographic differences in the prevalence of HCV in NHL but cannot provide any significant evidence for an association between HCV and/or GBV-C and B-cell NHLs.

Prevalence and clinical significance of GB virus type C/hepatitis G virus coinfection in patients with chronic hepatitis C undergoing antiviral therapy

Coinfection with GBV-C/HGV in patients with chronic hepatitis C (CHC) may influence clinical course and response rates of antiviral therapy. Aim of the study was to investigate the prevalence of GBV-C/HGV/HCV coinfection and its influence on outcome of interferon/ribavirin combination therapy. Three hundred and four patients with CHC [m/f = 211/93, age: 42 (18-65)] were investigated. HGV RNA detection was performed by polymerase chain reaction prior to and 6 months after the end of antiviral therapy. HGV/HCV coinfection could be identified in 37/304 (12.2%) patients with intravenous drug abuse as the most common source of infection (N = 21, (56.8%)). The predominant HCV genotype in coinfected individuals was HCV-3a (HCV-3a: 51.4%, HCV-1: 37.8%, HCV-4: 10.8%). HGV coinfection was more prevalent in patients infected with HCV-3 compared to HCV-1 or HCV-4 [19/45 (42.2%) vs. 14/185 (7.6%) vs. 4/52 (7.7%), P < 0.01]. Patients with HGV/HCV coinfection were younger [35 (18-56) vs. 43 (19-65), years; P < 0.01], and advanced fibrosis (F3-F4) was less frequent (22.2% vs. 42.9%, P < 0.05). A sustained virological response was achieved more frequently in HGV/HCV coinfected patients [26/37 (70.3%)] than in monoinfected patients [120/267 (44.9%), P < 0.01]. HGV RNA was undetectable in 65.7% of the coinfected patients at the end of follow-up. Intravenous drug abuse seems to be a major risk factor for HGV coinfection in patients with chronic hepatitis C. Coinfection with HGV does not worsen the clinical course of chronic hepatitis C or diminish response of HCV to antiviral therapy. Interferon/ribavirin combination therapy also clears HGV infection in a high proportion of cases.

GB virus C infection in pregnancy: maternal and perinatal importance of the infection

OBJECTIVES

The more effective way of transmission of GB virus C (GBV-C) is parenteral, but sexual and vertical transmission seem to be the main way of spreading. We evaluated the prevalence and the effect of GBV-C infection on pregnant women, vertical transmission and viral effects on the newborn.

STUDY DESIGN

This study has consecutively enrolled 879 pregnant women. All patients had blood sampling to determine GBV-C RNA, serologic tests for chronic viral infections and seric tests of hepatic damage. The newborns from infected mothers had blood sampling to detect the presence of GBV-C at birth, and after 3 and 6 months. Positive babies were checked until 18 months.

RESULTS

36 (4.1%) women resulted GBV-C positive. Among the positive patients none presented complications during pregnancy. Neither embryonic-fetal abnormalities nor relevant differences in fetal birth weight and week of gestation at delivery were found. 20 out of 36 babies had a follow-up. At birth, 13 (65%) babies were positive. 4 out of 9 vaginal deliveries (44%) and 9 out of 11 cesarean sections (82%) resulted positive to GBV-C RNA. The risk of GBV-C vertical transmission was not significantly increased by type of delivery (p=0.274). At 3 months, 13 babies were GBV-C positive (65%) and 7 were negative (35%). At the end of the follow-up, 9 babies were positive (45%), while 11 were negative (55%).

CONCLUSION

The percentage of patients positive to GBV-C RNA was comparatively high (4.1%). This prevalence, in a population without particular risk factors, confirms that common ways of transmission, such as the sexual and vertical ones, might have an important role in viral diffusion. Our data suggest that the infection does not influence the course of pregnancy. The rate of transmission found in our study is high. Type of delivery does not seem to be actually involved in vertical transmission and the protective role of cesarean section has not been confirmed.

[Extrahepatic symptoms in the course of GBV-C/HGV infection]

The GBV-C/HGV virus has clearly established transmission modes, mainly blood contamination, and occasionally sexual transmission. It is frequently found among transfused patients, intravenous drug abusers, and hemodialysis patients and often associated with HCV. Its hepatic pathogenicity is very weak, marked by a moderate and transitory cytolysis. Chronic carriage is possible, but does not lead to chronic hepatitis. Carriage can be maintained before the virus disappears. The authors report the case of a patient presenting with pleuropericarditis after a blood transfusion without any other etiology than infection by GBV-C/HGV virus. The possible extrahepatic pathogenicity of the virus is suggested. This hypothesis was rarely put forward.

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.

Seroprevalencia de las hepatitis virales en población general representativa de una zona básica de salud urbana en Castilla y León

INTRODUCTION

Viral hepatitis is a major social, health and economic problem worldwide, requiring strict epidemiological control.

METHODS

This study presents the viral hepatitis seroprevalence in a representative sample from an urban health care area in Valladolid (Spain).

RESULTS

Antibody prevalence was as follows: anti-HAV 52%; anti-HBc, 8.2%; anti-HCV, 1.1%; anti-HEV, 0.8%; and anti-HGV 5.8%. Prevalence of anti-HAV, anti-HBc and anti-HGV increased significantly with age (P < 0.005 in all cases). In individuals younger than 20, prevalence of anti-HAV was 3.8%, anti-HBc < 0.28% and anti-HGV 1.3%. In the 20-39 year-old group, seroprevalence against HAV was associated with low educational levels (P = 0.009) and with birth in other provinces (P = 0.016). Anti-HBc seroprevalence was mainly associated with three factors: prior hospitalization before 1990 (P = 0.002; OR 3.32 [1.48-7.42]); compulsory military service before 1990 (P < 0.0001; OR 37.33 [3.68-378.03]); and acupuncture treatments (P = 0.018; OR 57.75 [26.17-127.42]). Seroprevalence against HGV was associated with hospitalizations before 1990 (P = 0.019; OR = 2.969 [1.154-7.639]). Seropositive status to HCV revealed a transfusion history (2 cases), hospitalization (1 case) or drug addiction (1 case). Only one case among those seropositive to HEV had a history of a prior trip to a HEV-endemic area.

CONCLUSIONS

Our study shows that the seroprevalences of viral hepatitis in a representative sample of urban population of Castille and Leon are similar to the seroprevalences observed in the rest of Spain and other developed countries, lower than the ones observed in the studies performed in Spain in the last 20 years due to the measures of prophylaxis that were taken.

Effect of GB virus C viremia on HIV acquisition and HIV set-point

We performed both a case-control study and a cohort study to determine whether GB virus C (GBV-C) viremia prevents the acquisition of HIV infection or alters the HIV set-point after infection. The prevalence of GBV-C viremia in HIV-uninfected individuals who did and did not acquire HIV were similar (odds ratio 1.32; 95% confidence interval 0.6-2.6). Pre-existing GBV-C viremia at the time of HIV acquisition was also not associated with lower plasma HIV-RNA levels.

Active or prior GB virus C infection does not protect against vertical transmission of HIV in coinfected women from Tanzania

To determine whether GB virus C (GBV-C) infection is associated with protection against vertical transmission of human immunodeficiency virus (HIV), we tested 186 HIV-positive pregnant women for GBV-C. Neither active nor prior GBV-C infection was associated with a lower rate of HIV acquisition among infants. Thus, GBV-C does not appear to protect against perinatal HIV acquisition.

GB virus type C/hepatitis G virus: a non-pathogenic flavivirus associated with prolonged survival in HIV-infected individuals

GB virus C (GBV-C) is a common virus that does not appear to cause disease. GBV-C persists in up to 50% of exposed individuals, and virus replication appears to be in lymphocytes including CD4+ T cells. GBV-C infection is common among HIV-positive people, and several studies have found that HIV-positive individuals co-infected with GBV-C survive for statistically significantly longer periods of time than people without GBV-C. In vitro studies suggest that GBV-C inhibits HIV replication and alters cytokine, chemokine and chemokine receptor expression. Thus, GBV-C may be a major factor influencing the natural history of HIV disease.

[Is GB virus C alias "hepatitis" G virus involved in human pathology?]

GB virus-C alias "hepatitis" virus G was discovered in 1995 as a putative causative virus of non A-E hepatitis. It is a very common virus found in 1 to 5% of eligible blood donors in developed countries. Numerous studies over seven years led to the exclusion of its role as a significant etiological agent of hepatitis. Its in vivo replication site is still unknown. Its direct involvement in the induction of significant hepatic or extra-hepatic diseases could not be demonstrated. However, coinfections with other viruses may contribute to changes in the evolution of both liver disease (negatively) and HIV/AIDS (favourably). Today, no country has decided to screen GBV-C in blood donors. However, more studies are necessary before the absence of influence of GBV-C infection on human health in the context of other viral infections could be confirmed definitely. This article is a review of the literature on a possible involvement of GBV-C in pathologies whether associated or not to other infections.

Prevalence of hepatitis G virus infection and homology of different viral strains in Southern China

AIM: To investigate the prevalence of hepatitis G virus (HGV) infection and to analyse the homology of different HGV strains in Southern China.

METHODS: A total of 1993 sera from different groups in Guangdong, Hong Kong, and Yunnan were detected by reverse transcription polymerase chain reaction (RT-PCR). The nucleotide sequences of 5’untranslated region (5’UTR) derived from 20 strains and NS5 region from 3 strains were determined.

RESULTS: The positive rate of HGV RNA was 0.89% in community population, 2.57% in blood donors, 17.86% in intravenous drug abusers, 14.13% in patients with hemodialysis, 13.66% in those with hepatocellular carcinoma, 25.30% in non A-E hepatitis, 7.22% in hepatitis B, 12.73% in hepatitis C, 41.67% in patients received bone marrow transplantation, respectively. The homology was 90.40%-100% in 5’UTR among different strains, while that of NS5 region was 93.3%-94% in nucleotide sequence, and 97%-99.2% in amino acid sequence.

CONCLUSION: These results showed that there was a high incidence of HGV infection in patients from Southern China, being treated for bone marrow transplantation, hepatocellular carcinoma and those on haemodialysis. Furthermore, there was also a high frequency of co-infection of HGV with HBV, HCV, non A-E viral hepatitis and that among intravenous drug abusers. The study also showed that sequence variation in different strains was associated with geographical factors but there was no significant difference in 5’UTR in circulating viruses between different patient groups. Finally, by sequential analysis of viral species present in individual patients over a three months period there was no evidence of sequence variation in the 5' UTR.

Non-A to E hepatitis

PURPOSE OF THE REVIEW

The list of possible hepatotropic viruses continues to grow with the discovery of the GB virus-C, the TT virus and the SEN virus. There is emerging data on the biology of these newly discovered :In spite of continuing research into the pathogenicity of the GB virus-C and the TT virus, definite evidence linking them to acute or chronic liver disease is lacking. The SEN virus was reported in 2000, and although there seems to be an association between virus and transfusion-related hepatitis, more data are awaited before definite conclusions can be drawn. The effect of GB virus-C, the TT virus and the SEN virus co-infection on other viral and non-viral hepatitides has also been studied in some detail. Again, there is no definite evidence so far that these viruses modify other liver diseases.

SUMMARY

At the present time, diagnostic testing for these viruses does not seem to be warranted outside of clinical studies. The discovery of these viruses, however, paves the way for further research into novel viral agents that infect humans, other among hosts.