Characterization of human pegivirus infection in liver transplantation recipients

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.

Impact of JMJD6 on intrahepatic cholangiocarcinoma

The association of Jumonji domain-containing 6 (JMJD6) with the prognosis of various types of cancer has been demonstrated, except in intrahepatic cholangiocarcinoma (ICC). The present study aimed to clarify the impact of JMJD6 on ICC. The liver specimens of 51 patients who underwent surgery for ICC were analyzed for JMJD6 expression using immunohistochemistry staining. The relationship between clinicopathological factors and JMJD6 expression was investigated. The cellular activity was also evaluated in JMJD6 knocked down cells with Transwell migration assay and viability assay. In the immunohistochemistry staining of clinical samples, high expression of JMJD6 was seen in 32 of 51 samples. High expression was also associated with improved overall survival (OS) and recurrence-free survival (RFS) (P=0.0033 and 0.048, respectively). Further analyses revealed that higher JMJD6 expression was one of the improved independent prognostic factors of OS and RFS. Expression of JMJD6 was knocked down in commercial culture cell lines of ICC, and RNA and protein were extracted to analyze the downstream gene expression using RNA-sequencing and western blotting. JMJD6 knockdown was associated with higher programmed death-ligand 1 (PD-L1) expression in RNA-sequencing and western blotting. In addition, PD-L1 expression was higher in JMJD6 low expression clinical samples when measured using immunohistochemistry staining. In conclusion, high expression of JMJD6 was an independent favorable prognostic factor of ICC. JMJD6 may influence the prognosis of ICC through the regulation of PD-L1 expression.

Target Enrichment Metagenomics Reveals Human Pegivirus-1 in Pediatric Hematopoietic Stem Cell Transplantation Recipients

Human pegivirus-1 (HPgV-1) is a lymphotropic human virus, typically considered nonpathogenic, but its infection can sometimes cause persistent viremia both in immunocompetent and immunosuppressed individuals. In a viral discovery research program in hematopoietic stem cell transplant (HSCT) pediatric patients, HPgV-1 was detected in 3 out of 14 patients (21.4%) using a target enrichment next-generation sequencing method, and the presence of the viruses was confirmed by agent-specific qRT-PCR assays. For the first time in this patient cohort, complete genomes of HPgV-1 were acquired and characterized. Phylogenetic analyses indicated that two patients had HPgV-1 genotype 2 and one had HPgV-1 genotype 3. Intra-host genomic variations were described and discussed. Our results highlight the necessity to screen HSCT patients and blood and stem cell donors to reduce the potential risk of HPgV-1 transmission.

Transcriptomic profiling of blood from autoimmune hepatitis patients reveals potential mechanisms with implications for management

Autoimmune hepatitis (AIH) is a poorly understood, chronic disease, for which corticosteroids are still the mainstay of therapy and most patients undergo liver biopsy to obtain a diagnosis. We aimed to determine if there was a transcriptomic signature of AIH in the peripheral blood and investigate underlying biologic pathways revealed by gene expression analysis. Whole blood RNA from 75 AIH patients and 25 healthy volunteers was extracted and sequenced. Differential gene expression analysis revealed 249 genes that were significantly differentially expressed in AIH patients compared to controls. Using a random forest algorithm, we determined that less than 10 genes were sufficient to differentiate the two groups in our cohort. Interferon signaling was more active in AIH samples compared to controls, regardless of treatment status. Pegivirus sequences were detected in five AIH samples and 1 healthy sample. The gene expression data and clinical metadata were used to determine 12 genes that were significantly associated with advanced fibrosis in AIH. AIH patients with a partial response to therapy demonstrated decreased evidence of a CD8+ T cell gene expression signal. These findings represent progress in understanding a disease in need of better tests, therapies, and biomarkers.

Human pegivirus infection after transplant: Is there an impact?

The microbiome's role in transplantation has received growing interest, but the role of virome remains understudied. Pegiviruses are single-stranded positive-sense RNA viruses, historically associated with liver disease, but their path-ogenicity is controversial. In the transplantation setting, pegivirus infection does not seem to have a negative impact on the outcomes of solid-organ and hematopoietic stem cell transplant recipients. However, the role of pegiviruses as proxies in immunosuppression monitoring brings novelty to the field of virome research in immunocompromised individuals. The possible immunomodulatory effect of pegivirus infections remains to be elucidated in further trials.

Human pegivirus type 1 infection in kidney transplant recipients: Replication kinetics and clinical correlates

BACKGROUND

Increasing evidence suggests that infection with the nonpathogenic human pegivirus type 1 (HPgV-1) exerts a clinical benefit in human immunodeficiency virus (HIV) patients, which could be attributable to immunomodulatory effects. Whether this impact can be extrapolated to kidney transplantation (KT) remains largely unknown.

METHODS

We measured plasma HPgV-1 RNA by real-time polymerase chain reaction targeting the 5' untranslated region at various points (pretransplantation, day 7, months 1, 3, 6, and 12) in 199 KT recipients. Study outcomes included posttransplant serious infection, immunosuppression-related adverse event (opportunistic infection and/or de novo cancer), and acute graft rejection.

RESULTS

HPgV-1 infection was demonstrated in 52 (26.1%) patients, with rates increasing from 14.7% at baseline to 19.1% by month 12 (p-value = .071). De novo infection occurred in 13.8% of patients with no detectable HPgV-1 RNA before transplantation. Double-organ (liver-kidney or kidney-pancreas) transplantation (odds ratio [OR]: 5.62; 95% confidence interval [CI]: 1.52-20.82) and donation after brain death (OR: 2.21; 95% CI: 1.00-4.88) were associated with posttransplant HPgV-1 infection, whereas pretransplant hypertension was protective (OR: 0.23; 95% CI: 0.09-0.55). There were no significant differences in the incidence of study outcomes according to HPgV-1 status. Plasma HPgV-1 RNA levels at different points did not significantly differ between patients that subsequently developed outcomes and those remaining free from these events. No correlation between HPgV-1 RNA and immune parameters or torque teno virus DNA load was observed either.

CONCLUSION

Unlike patients living with HIV, HPgV-1 infection does not seem to influence patient or graft outcomes after KT.

Human pegivirus 1 infection in lung transplant recipients: Prevalence, clinical relevance and kinetics of viral replication under immunosuppressive therapy

BACKGROUND

Human pegivirus 1 (HPgV1) may cause persistent infections in immunocompetent and immunosuppressed individuals. Its clinical relevance, however, has not been determined. Previous studies have described a higher prevalence of HPgV1 infection in organ transplant recipients compared to healthy controls, but its occurrence in lung transplant recipients (LTRs) and its association with immunosuppressive therapy has not been assessed.

OBJECTIVES

The aim of this study was to evaluate the prevalence and clinical significance of HPgV1 infection in LTRs, and to compare HPgV1 loads and kinetics to Torque Teno Virus (TTV) kinetics, which reflects the level of immunosuppression.

STUDY DESIGN

From each of 110 LTRs, five consecutive plasma samples were collected within the first year after transplantation and tested for HPgV1 RNA and TTV DNA loads by quantitative PCR. Data were related to demographic data and clinical parameters followed up for 3 years post transplantation.

RESULTS

HPgV1 prevalence in LTRs was 18,2%. HPgV1 detection was significantly associated with younger age, but not with graft rejections or other microbial infections. The viral replication level remained unaffected by immunosuppressive therapy. This was in contrast to TTV loads which increased after initiation of immunosuppressive therapy, independent of the patients' HPgV1 infection status.

CONCLUSIONS

In contrast to TTV, HPgV1 kinetics do not reflect the level of immunosuppression after lung transplantation, and there is no correlation between the replication of both persistent viruses in the post transplantation follow up. Thus the individual virus host interactions seem to differ substantially and require further investigation.

Towards an Ensemble Vaccine against the Pegivirus Using Computational Modelling Approaches and Its Validation through In Silico Cloning and Immune Simulation

Pegivirus, HPgV, which was earlier known as Gb virus and hepatitis G virus, is an enveloped, positive-stranded RNA and lymphotropic virus classified into the Flaviviridae family. The transmission routes primarily involve blood products, and infections are worldwide, leading up to 25% of persistent infections. To date, no effective therapeutic means are available to clear Pegivirus infections. Effective vaccine therapeutics is the best alternative to manage this disease and any associated potential pandemic. Thus, whole proteome-based mining of immunogenic peptides, i.e., CTL (cytotoxic T lymphocytes), HTL (helper T lymphocytes), and B cell epitopes, was mapped to design a vaccine ensemble. Our investigation revealed that 29 different epitopes impart a critical role in immune response induction, which was also validated by exploring its physiochemical properties and experimental feasibility. In silico expression and host immune simulation were examined using an agent-based modeling approach and confirmed the induction of both primary and secondary immune factors such as IL, cytokines, and antibodies. The current study warrants further lab experiments to demonstrate its efficacy and safety.

Human pegivirus type 1 infection in Asia-A review of the literature

The human pegivirus type 1 (HPgV-1)-as known as hepatitis G virus and GB virus C-is a common single-stranded RNA flavivirus. Because few studies have demonstrated an association between HPgV-1 infection and disease, screening for HPgV-1 is not performed routinely. Nonetheless, a beneficial impact of HPgV-1 infection on HIV disease progression has been reported in multiple studies. Given the burden of HIV in Asia and the complex interactions between viral co-infections and the host, we provide a comprehensive overview of the existing data from Asia on HPgV-1 infection, including the prevalence and circulating genotypes in all Asian countries with data reported. This review highlights the research conducted thus far and emphasizes the need for additional studies on HPgV-1 across the Asian continent.

Beyond Cytomegalovirus and Epstein-Barr Virus: a Review of Viruses Composing the Blood Virome of Solid Organ Transplant and Hematopoietic Stem Cell Transplant Recipients

Viral primary infections and reactivations are common complications in patients after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) and are associated with high morbidity and mortality. Among these patients, viral infections are frequently associated with viremia. Beyond the usual well-known viruses that are part of the routine clinical management of transplant recipients, numerous other viral signatures or genomes can be identified in the blood of these patients. The identification of novel viral species and variants by metagenomic next-generation sequencing has opened up a new field of investigation and new paradigms. Thus, there is a need to thoroughly describe the state of knowledge in this field with a review of all viral infections that should be scrutinized in high-risk populations. Here, we review the eukaryotic DNA and RNA viruses identified in blood, plasma, or serum samples of pediatric and adult SOT/HSCT recipients and the prevalence of their detection, with a particular focus on recently identified viruses and those for which their potential association with disease remains to be investigated, such as members of the Polyomaviridae, Anelloviridae, Flaviviridae, and Astroviridae families. Current knowledge of the clinical significance of these viral infections with associated viremia among transplant recipients is also discussed. To ensure a comprehensive description in these two populations, individuals described as healthy (mostly blood donors) are considered for comparative purposes. The list of viruses that should be on the clinicians' radar is certainly incomplete and will expand, but the challenge is to identify those of possible clinical significance.

Rimonabant suppresses RNA transcription of hepatitis B virus by inhibiting hepatocyte nuclear factor 4α

Chronic infection with hepatitis B virus (HBV) sometime induces lethal cirrhosis and hepatocellular carcinoma. Although nucleot(s)ide analogs are used as main treatment for HBV infection, the emergence of the drug-resistant viruses has become a problem. To discover novel antivirals with low side effects and low risk of emergence of resistant viruses, screening for anti-HBV compounds was performed with compound libraries of inhibitors targeting G-protein-coupled receptors (GPCRs). HepG2-hNTCP C4 cells infected with HBV were treated with various GPCR inhibitors and harvested at 14 day postinfection for quantification of core protein in the first screening or relaxed circular DNA in the second screening. Finally, we identified a cannabinoid receptor 1 inhibitor, rimonabant, as a candidate showing anti-HBV effect. In HepG2-hNTCP C4 cells, treatment with rimonabant suppressed HBV propagation at the viral RNA transcription step but had no effect on entry or covalently closed circular DNA level. The values of half maximal inhibitory concentration, half maximal effective concentration, and selectivity index of rimonabant in primary human hepatocyte (PHH) are 2.77 μm, 40.4 μm, and 14.6, respectively. Transcriptome analysis of rimonabant-treated primary hepatocytes by RNA sequencing revealed that the transcriptional activity of hepatocyte nuclear factor 4α (HNF4α), which is known to stimulate viral RNA synthesis, was depressed. By treatment of PHH with rimonabant, the expression level of HNF4α protein and the production of the messenger RNAs (mRNAs) of downstream factors promoted by HNF4α were reduced while the amount of HNF4α mRNA was not altered. These results suggest that treatment with rimonabant suppresses HBV propagation through the inhibition of HNF4α activity.