Molecular and Clinical Profiles of Human Pegivirus Type 1 Infection in Individuals Living with HIV-1 in the Extreme South of Brazil

Pegivirus Detection in Cerebrospinal Fluid from Patients with Central Nervous System Infections of Unknown Etiology in Brazil by Viral Metagenomics

Metagenomic next-generation sequencing (mNGS) methodology serves as an excellent supplement in cases where diagnosis is challenging to establish through conventional laboratory tests, and its usage is increasingly prevalent. Examining the causes of infectious diseases in the central nervous system (CNS) is vital for understanding their spread, managing outbreaks, and effective patient care. In a study conducted in the state of São Paulo, Brazil, cerebrospinal fluid (CSF) samples from 500 patients with CNS diseases of indeterminate etiology, collected between 2017 and 2021, were analyzed. Employing a mNGS approach, we obtained the complete coding sequence of Pegivirus hominis (HPgV) genotype 2 in a sample from a patient with encephalitis (named IAL-425/BRA/SP/2019); no other pathogen was detected. Subsequently, to determine the extent of this virus's presence, both polymerase chain reaction (PCR) and/or real-time PCR assays were utilized on the entire collection. The presence of the virus was identified in 4.0% of the samples analyzed. This research constitutes the first report of HPgV detection in CSF samples in South America. Analysis of the IAL-425 genome (9107 nt) revealed a 90% nucleotide identity with HPgV strains from various countries. Evolutionary analyses suggest that HPgV is both endemic and extensively distributed. The direct involvement of HPgV in CNS infections in these patients remains uncertain.

A Case of Persistent Human Pegivirus Infection in Two Separate Pregnancies of a Woman

Human pegivirus (HPgV) is best known for persistent, presumably non-pathogenic, infection and a propensity to co-infect with human immunodeficiency virus or hepatitis C virus. However, unique attributes, such as the increased risk of malignancy or immune modulation, have been recently recognized for HPgV. We have identified a unique case of a woman with high levels HPgV infection in two pregnancies, which occurred 4 years apart and without evidence of human immunodeficiency virus or hepatitis C virus infection. The second pregnancy was complicated by congenital heart disease. A high level of HPgV infection was detected in the maternal blood from different trimesters by RT-PCR and identified as HPgV type 1 genotype 2 in both pregnancies. In the second pregnancy, the decidua and intervillous tissue of the placenta were positive for HPgV by PCR but not the chorion or cord blood (from both pregnancies), suggesting no vertical transmission despite high levels of viremia. The HPgV genome sequence was remarkably conserved over the 4 years. Using VirScan, sera antibodies for HPgV were detected in the first trimester of both pregnancies. We observed the same anti-HPgV antibodies against the non-structural NS5 protein in both pregnancies, suggesting a similar non-E2 protein humoral immune response over time. To the best of our knowledge, this is the first report of persistent HPgV infection involving placental tissues with no clear indication of vertical transmission. Our results reveal a more elaborate viral-host interaction than previously reported, expand our knowledge about tropism, and opens avenues for exploring the replication sites of this virus.

Regional mutations in CHIKV-ECSA genomes and detection of other viruses in the serum of acute febrile patients by a metagenomic approach in Mato Grosso, Central-Western Brazil, 2018

Mato Grosso (MT) State is part of central western Brazil and has a tropical permissive environment that favors arbovirus outbreaks. A metagenomic approach was used to identify viral genomes in seven pools of serum from patients (n=65) with acute febrile disease. Seven chikungunya virus (CHIKV) genomes were determined, showing four amino acid changes found only in CHIKV genomes obtained in MT since 2018: nsP2:T31I, nsP3: A388V, E3:T201I and E3:H57R, in addition to other mutations in E1, nsP2 and nsP4. Six parvovirus B19 (B19V) genotype I genomes (4771-5131 nt) showed four aa alterations (NS1:N473D, R579Q; VP1:I716T; and 11 kDa:V44A) compared to most similar B19V from the USA. Coinfection between CHIKV and B19V was evidenced in 22/65 (33.8%) patients by RT‒PCR and PCR, respectively. Other viruses found in these pools include human pegivirus C, torque teno virus 3, an unclassified TTV and torque teno mini virus. Metagenomics represents a useful approach to detect viruses in the serum of acute febrile patients suspected of arbovirus disease.

Tissue presentation of human pegivirus infection in liver transplanted recipients

Human pegivirus-1 (HPgV-1) is known for its protective role in HIV co-infected individuals. This immunomodulatory effect raised questions concerning the possible role of HPgV-1 infection and the risk of rejection in liver transplanted patients. We aimed to evaluate the possible protective effect of HPgV-1 on graft outcome of liver transplanted patients. A total of 283 patients were recruited. Formalin-fixed paraffin-embedded tissue samples were collected from the explanted liver. HBV-DNA, HCV-RNA, and HPgV-1-RNA were determined using PCR and multiplex RT-PCR assays. The clinical course of patients including the occurrence of acute cellular rejection was compared between HPgV-1-infected vs. uninfected patients. HBV-DNA, HCV-RNA and HPgV-1-RNA were detected in 42.6%, 4.9%, and 7.8% of samples, respectively. None of the HPgV-1-infected patients experienced graft rejection. Group LASSO logistic regression revealed that HPgV-1 infection was the only factor which significantly reduced the odds of graft rejection (OR = 0.5, 95% CI = 0.29-0.89). No significant association was found between the presence of HPgV-1 with HBV and HCV infections. The lack of graft rejection in HPgV-1-infected liver transplanted patients might indicate a possible role of this virus for graft surveillance. Since these are still preliminary findings, prospective studies should further elucidate the role of HPgV-1 in liver transplantation outcomes.

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.

METAVIROME COMPOSITION OF BRAZILIAN BLOOD DONORS POSITIVE FOR THE ROUTINELY TESTED BLOOD-BORNE INFECTIONS

Viral metagenomics is widely applied to characterize emerging viral pathogens but it can also reveal the virome composition in health and disease. The evaluation of the virome in healthy blood donors can provide important knowledge on possible transfusion threats. Currently, there is still a paucity of information regarding the virome of blood donors who test positive for routinely tested blood-borne infections. Such analysis may reveal co-infections which in turn appear to be crucial for transfusion medicine and for patient management. The aim of this study was to evaluate the metavirome in blood donors who tested positive for routinely tested blood-borne infections, the information for which is important for transfusion medicine and blood donor management. For this purpose, we analyzed 18 blood donations obtained from HIV and HBV-infected blood donors from the Brazilian Amazon (Amapa state) and 11 HIV, HBV, HCV, syphilis and Chagas disease - positive blood donations obtained from blood donors sampled in South Brazil (Rio Grande do Sul state). We additionally included a control group of 20 blood donors obtained from Southeast Brazil (State of São Paulo). Samples were assembled in pools and sequenced by the Illumina NovaSeq 6000 platform. To link a given virus with geographic region or type of blood donor, we performed supervised machine learning classification (fingerprint analysis). The virome of both locations was predominantly composed of commensal viruses. However, in HBV-infected blood donors from the Brazilian Amazon, the Human Pegivirus-1 (HPgV-1) reads were prevailing, while in HIV-infected donors from the same location, the torque teno virus (TTV) reads expressive abundance. In blood donors from South Brazil, the most abundant reads were classified as Human endogenous retrovirus K (HERV-K). Putative emerging viruses like the Human gemykibivirus-2 (HuGkV-2) were exclusively identified in samples from the Brazilian Amazon. The fingerprint analysis demonstrated that the HERV-K, TTV-7, 13, and 15 were statistically important for the infected blood donors, while TTV-5, 12 and 20 were linked to geographic localization. Our study revealed differences in the viral composition among blood donors who tested positive for routinely tested blood-borne infections from two different Brazilian regions and indicated the presence of putative emerging viruses in samples obtained from the Amazon. Together our results show that the presence of specific commensal viruses may be related donor infection status but additional investigations including larger study groups and samples from other Brazilian regions are needed to confirm this hypothesis.

Role of human Pegivirus infections in whole Plasmodium falciparum sporozoite vaccination and controlled human malaria infection in African volunteers

BACKGROUND

Diverse vaccination outcomes and protection levels among different populations pose a serious challenge to the development of an effective malaria vaccine. Co-infections are among many factors associated with immune dysfunction and sub-optimal vaccination outcomes. Chronic, asymptomatic viral infections can contribute to the modulation of vaccine efficacy through various mechanisms. Human Pegivirus-1 (HPgV-1) persists in immune cells thereby potentially modulating immune responses. We investigated whether Pegivirus infection influences vaccine-induced responses and protection in African volunteers undergoing whole P. falciparum sporozoites-based malaria vaccination and controlled human malaria infections (CHMI).

METHODS

HPgV-1 prevalence was quantified by RT-qPCR in plasma samples of 96 individuals before, post vaccination with PfSPZ Vaccine and after CHMI in cohorts from Tanzania and Equatorial Guinea. The impact of HPgV-1 infection was evaluated on (1) systemic cytokine and chemokine levels measured by Luminex, (2) PfCSP-specific antibody titers quantified by ELISA, (3) asexual blood-stage parasitemia pre-patent periods and parasite multiplication rates, (4) HPgV-1 RNA levels upon asexual blood-stage parasitemia induced by CHMI.

RESULTS

The prevalence of HPgV-1 was 29.2% (28/96) and sequence analysis of the 5' UTR and E2 regions revealed the predominance of genotypes 1, 2 and 5. HPgV-1 infection was associated with elevated systemic levels of IL-2 and IL-17A. Comparable vaccine-induced anti-PfCSP antibody titers, asexual blood-stage multiplication rates and pre-patent periods were observed in HPgV-1 positive and negative individuals. However, a tendency for higher protection levels was detected in the HPgV-1 positive group (62.5%) compared to the negative one (51.6%) following CHMI. HPgV-1 viremia levels were not significantly altered after CHMI.

CONCLUSIONS

HPgV-1 infection did not alter PfSPZ Vaccine elicited levels of PfCSP-specific antibody responses and parasite multiplication rates. Ongoing HPgV-1 infection appears to improve to some degree protection against CHMI in PfSPZ-vaccinated individuals. This is likely through modulation of immune system activation and systemic cytokines as higher levels of IL-2 and IL17A were observed in HPgV-1 infected individuals. CHMI is safe and well tolerated in HPgV-1 infected individuals. Identification of cell types and mechanisms of both silent and productive infection in individuals will help to unravel the biology of this widely present but largely under-researched virus.

Human pegivirus (HPgV, GBV-C) RNA in volunteer blood donors from a public hemotherapy service in Northern Brazil

BACKGROUND

Human pegivirus (HPgV)-formerly known as GBV-C-is a member of the Flaviviridae family and belongs to the species Pegivirus C. It is a non-pathogenic virus and is transmitted among humans mainly through the exposure to contaminated blood and is often associated with human immunodeficiency virus (HIV) infection, among other viruses. This study aimed to determine the prevalence of HPgV viremia, its association with HIV and clinical epidemiological factors, as well as the full-length sequencing and genome characterization of HPgV recovered from blood donors of the HEMOPA Foundation in Belém-PA-Brazil.

METHODS

Plasma samples were obtained from 459 donors, tested for the presence of HPgV RNA by the RT-qPCR. From these, a total of 26 RT-qPCR positive samples were submitted to the NGS sequencing approach in order to obtain the full genome. Genome characterization and phylogenetic analysis were conducted.

RESULTS

The prevalence of HPgV was 12.42%. We observed the highest prevalences among donors aged between 18 and 30 years old (16.5%), with brown skin color (13.2%) and men (15.8%). The newly diagnosed HIV-1 prevalence was 26.67%. The HPgV genotype 2 (2a and 2b) was identified. No data on viral load value was found to corroborate the protective effect of HPgV on HIV evolution.

CONCLUSIONS

This study provided information regarding the HPgV infection among blood donors from HEMOPA Foundation. Furthermore, we genetically characterized the HPgV circulating strains and described by the first time nearly complete genomes of genotype 2 in Brazilian Amazon.

Low prevalence of human pegivirus 1 (HPgV-1) in HTLV-1 carriers from Belém, Pará, North Region of Brazil

Introduction

Human pegivirus 1 (HPgV-1) is a single-stranded, positive-sense RNA virus belonging to the Flaviviridae family with limited cause-effect evidence of the causation of human diseases. However, studies have shown a potential beneficial impact of HPgV-1 coinfection in HIV disease progression. Human T lymphotropic virus-1 (HTLV-1) is a retrovirus known for causing diseases, especially in muscle and white blood cells, in approximately 5% of patients. Thus, this study aimed to investigate the potential effects of an HPgV-1 infection in patients carrying HTLV-1 in the state of Pará in the North Region of Brazil.

Methods

A group of HTLV-1 carriers was compared to healthy controls. Blood samples were collected, data from medical regards were collected, and a questionnaire was administered. HPgV-1 and HTLV-1 positivity was determined by quantitative polymerase chain reaction (qRT-PCR). The data were analyzed to correlate the effects of HPgV-1 coinfection in HTLV-1 carriers.

Results

A total of 158 samples were included in the study: 74 HTLV-1-positive patients (46,8%) and 84 healthy controls (53,2%). The overall HPgV-1 positivity rate was 7.6% (12/158), resulting in a prevalence of 5.4% (4/74) and 9.5% (8/84) in HTLV-1 carriers and healthy controls, respectively. No significant differences were found when comparing any clinical or demographic data between groups.

Conclusion

This study indicated that the prevalence of HPgV-1 infection is low in HTLV-1 carriers in Belém, Pará, and probably does not alter the clinical course of HTLV-1 infection, however, further studies are still needed.