Human pegivirus (HPgV-1), previously known as GB virus C (GBV-C) or hepatitis G virus (HGV), is a single-stranded positive RNA virus belonging to the genus Pegivirus of the Flaviviridae family. It is transmitted by percutaneous injuries (PIs), contaminated blood and/or blood products, sexual contact, and vertical mother-to-child transmission. It is widely prevalent in general population, especially in high-risk groups. HPgV-1 viremia is typically cleared within the first 1-2 years of infection in most healthy individuals, but may persist for longer periods of time in immunocompromised individuals and/or those co-infected by other viruses. A large body of evidences indicate that HPgV-1 persistent infection has a beneficial clinical effect on many infectious diseases, such as acquired immunodeficiency syndrome (AIDS) and hepatitis C. The beneficial effects seem to be related to a significant reduction of immune activation, and/or the inhabitation of co-infected viruses (e.g. HIV-1). HPgV-1 has a broad cellular tropism for lymphoid and myeloid cells, and preferentially replicates in bone marrow and spleen without cytopathic effect, implying a therapeutic potential. The paper aims to summarize the natural history, prevalence and distribution characteristics, and pathogenesis of HPgV-1, and discuss its association with other human viral diseases, and potential use in therapy as a biovaccine or viral vector.

In this study, using a viral metagenomic method, we investigated the composition of virome in blood and cancer tissue samples that were collected from 25 patients with lung adenocarcinoma. Results indicated that virus sequences showing similarity to human pegivirus (HPgV), anellovirus, human endogenous retrovirus (HERV), and polyomavirus were recovered from this cohort. Three different complete genomes of HPgV were acquired from the blood samples and one complete genome of polyomavirus was determined from the cancer tissue sample. Phylogenetic analysis indicated that the three HPgV strains belonged to genotype 3 and the polyomavirus showed the highest sequence identity (99.73%) to trichodysplasia spinulosa-associated polyomavirus. PCR screening results indicated that the three HPgVs were present in 5 out of the 25 blood samples and the polyomavirus only existed in a cancer tissue sample pool. Whether infections with viruses have an association with lung cancer needs further study with a larger size of sampling.

Pathogens associated with haemorrhagic fever commonly have zoonotic origins. The first documented imported case of likely viral severe haemorrhagic fever in Sweden occurred in 1990. Despite extensive study, no aetiological agent was identified. Following retrospective investigation with total RNA-sequencing of samples collected between 7 and 36 days from onset of symptoms we identified dengue virus 3 (DENV-3) and a human pegivirus (HPgV). We conclude that the patient likely suffered from haemorrhagic symptoms due to an atypical severe and undiagnosed dengue infection.

OBJECTIVE: To investigate the prevalence, risk factors, and genotypes of human pegivirus type 1 (HPgV-1) in hematopoietic stem cell transplantation (HSCT) patients.
METHODS: One hundred and eighty-eight HSCT patients and 694 healthy blood donors were investigated retrospectively, including their demographic information and HPgV-1 infection status.
RESULTS: When compared with healthy blood donors, a significantly higher HPgV-1 prevalence (18.6% vs. 2.3%) and a high risk of HPgV-1 infection (odds ratio 9.7) were observed in HSCT patients (p<0.05). The number of transfusions in patients with RNA test conversions (negative to positive) was significantly higher than the number in patients without conversions (negative to negative) (median 10 vs. 1) (p<0.05). Although HPgV-1 infection is independent of age, sex, blood type, hepatitis B virus infection, hepatitis C virus infection, marriage status, and type of hematological malignancy (p>0.05), race might be a risk factor for infection (p<0.05). The great majority (95.7%) of HPgV-1-positive patients were infected with genotype 3.
CONCLUSIONS: HPgV-1 is highly prevalent in HSCT patients, and blood transfusions can significantly increase the risk of HPgV-1 infection. Thus, HPgV-1 screening is recommended in HSCT patients to reduce the potential impact of infection on survival, as well as in their blood and stem cell donors to reduce the risk of infection after transfusions, unless the beneficial effects of HPgV-1 infection in immunocompromised patients are clearly confirmed.