Direct evidence for GB virus C/hepatitis G virus (GBV-C/HGV) superinfection: elimination of resident viral strain by donor strain in a patient undergoing liver transplantation

Expansion of Betatorquevirus and/or Gammatorquevirus in Patients with Severe Clinical Outcomes of the Liver Diseases

Anellovirus (AV) is a ubiquitous virus in the human population. Individuals can be infected with multiple AV genera and species to form a heterogeneous repertoire, termed the anellome. Using advanced methods, we examined the anellomes from 12 paired serum and liver samples, as well as 2701 subjects with different clinical diagnoses. Overall, anellomes are remarkably individualized, with significant among-group differences (Kruskal-Wallis test p = 6.6 × 10-162 for richness and p = 7.48 × 10-162 for Shannon entropy). High dissimilarity scores (beta diversity) were observed between patient groups, except for paired serum and liver samples. At the population level, the relative abundance of combinational AV genus Betatorquevirus (torque teno mini viruses, TTMV), and Gammatorquevirus (torque teno midi viruses, TTMDV) exhibited an exponential distribution with a low bound point at 32%. Defined by this value, the AV TTMV/TTMDV-expanded anellome was significantly enriched among patients with acute liver failure (31.7%) and liver transplantation (40.7%), compared with other patient groups (χ2 test: p = 4.1 × 10-8-3.2 × 10-3). Therefore, anellome heterogeneity may be predictive of clinical outcomes in certain diseases, such as liver disease. The consistency of anellome between paired serum and liver samples indicates that a liquid biopsy approach would be suitable for longitudinal studies to clarify the causality of the AV TTMV/TTMDV-expanded anellome in the outcomes of liver disease.

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.

High prevalence and autochtonous transmission of human pegivirus (HPgV-1) in blood donors in the extreme southern of Brazil

Recent studies have suggested that human pegivirus 1 (HPgV-1) may have some pathogenic potential. In the southernmost region of Brazil, studies on HPgV-1 are scarce, and circulating genotypes have not yet been identified. The current study aimed to evaluate the prevalence of HPgV-1 among blood donors from the southernmost region of Brazil and identify the genotypes involved with associated factors. A cross-sectional study was conducted with 281 blood donors, who had their plasma subjected to RNA extraction, complementary DNA synthesis, HPgV-1 detection by nested polymerase chain reaction, and subsequent genotyping. The observed prevalence of HPgV-1-RNA was 21.7%. The only variable that was significantly associated with virus infection was the relationship status of the donor. Single or no fixed partner blood donors were twice as likely to have HPgV-1 (95% CI, 1.12 to 4.56; P = 0.02). Genotype 2-subtypes 2b (69%) and 2a (29%)-was the most prevalent. In the absence of risk factors for parenteral transmission, it is likely that sexual transmission was the route of infection in the individuals studied. Further work will be needed to determine whether this virus is inert in the population, or if there are potential deleterious effects in infected individuals.

Human pegivirus (HPgV) infection in sub-Saharan Africa-A call for a renewed research agenda

The human pegivirus (HPgV)-formerly GB virus C-has a beneficial impact on HIV disease progression that has been described in multiple studies. Given the high prevalence of HIV in sub-Saharan Africa and the continuing need to suppress HIV replication, this review provides a comprehensive overview of the existing data on HPgV infection in sub-Saharan Africa, with a particular focus on studies of prevalence and the circulating HPgV genotypes. This review also highlights the need for additional studies of HPgV conducted on the African continent and proposes a research agenda for evaluation of HPgV.

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.

[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.