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Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis. Numerous studies have investigated the dynamics of HEV infection markers, but the most suitable marker for diagnosing ongoing or recent HEV infection remains to be determined. Recent evidence suggests that serum antigen testing is superior to serum IgM and RNA quantification. Moreover, it has been found that infected individuals excrete HEV antigen in significant quantities through urine. To address this question, we conducted a longitudinal analysis involving 16 patients with acute or chronic HEV infection in an area where genotype 3 HEV is prevalent. Our findings indicate that the diagnostic and monitoring capabilities of antigen testing for HEV infection can be further enhanced by measuring it in urine. Additionally, we were able to demonstrate that this enhancement is likely due to the presence of HEV-reactive IgG in blood plasma, which hampers efficient detection of HEV antigen through sandwich ELISA. In conclusion, urine-based antigen testing appears to be superior to measuring anti-HEV antibodies or viral RNA for diagnosing suspected HEV infection and monitoring ongoing infections.

Background and Aims: The HEV is a small positive-sense RNA virus that encodes a cytoplasmic form of the capsid protein (ORF2c), essential for virion structure, and a secreted glycosylated form (ORF2s) that accumulates at high titer in serum and can mask neutralizing epitopes. We explored the contribution of ORF2s to HEV replication and its role in generating antibodies against ORF2 in a nonhuman primate model., Approach and Results: We used a recombinant HEV genotype 3 variant that does not express ORF2s due to the introduction of stop codons (ORF2s mut ). Rhesus macaques (RMs) were given intrahepatic injections of infectious wildtype HEV (ORF2s wt ) RNA or a variant lacking ORF2s expression (ORF2s mut ). The replication of the ORF2s mut virus was delayed by ~2 weeks compared with ORF2s wt , and peak titers were nearly tenfold lower. Reversions of the 3 mutations that blocked ORF2s expression were not detected in the ORF2s mut genomes, indicating genetic stability. However, serum antibodies against ORF2 were transiently detected in RMs infected with ORF2s mut , whereas they were long-lasting in RMs infected with ORF2s wt . Moreover, RMs infected with ORF2s mut were more susceptible to reinfection, as evidenced by the viral RNA detected in fecal samples and the expansion of HEV-specific CD8 + T cells., Conclusions: These findings indicate that ORF2s may be dispensable for viral replication in vivo but is required for long-lived antibody-mediated responses that protect against HEV re-exposure., (Copyright © 2023 American Association for the Study of Liver Diseases.)

Background & Aims: Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide and is mainly transmitted via the fecal-oral route or through consumption of contaminated food products. Due to the lack of efficient cell culture systems for the propagation of HEV, limited data regarding its sensitivity to chemical disinfectants are available. Consequently, preventive and evidence-based hygienic guidelines on HEV disinfection are lacking., Methods: We used a robust HEV genotype 3 cell culture model which enables quantification of viral infection of quasi-enveloped and naked HEV particles. For HEV genotype 1 infections, we used the primary isolate Sar55 in a fecal suspension. Standardized quantitative suspension tests using end point dilution and large-volume plating were performed for the determination of virucidal activity of alcohols (1-propanol, 2-propanol, ethanol), WHO disinfectant formulations and 5 different commercial hand disinfectants against HEV. Iodixanol gradients were conducted to elucidate the influence of ethanol on quasi-enveloped viral particles., Results: Naked and quasi-enveloped HEV was resistant to alcohols as well as alcohol-based formulations recommended by the WHO. Of the tested commercial hand disinfectants only 1 product displayed virucidal activity against HEV. This activity could be linked to phosphoric acid as an essential ingredient. Finally, we observed that ethanol and possibly non-active alcohol-based disinfectants disrupt the quasi-envelope structure of HEV particles, while leaving the highly transmissible and infectious naked virions intact., Conclusions: Different alcohols and alcohol-based hand disinfectants were insufficient to eliminate HEV infectivity with the exception of 1 commercial ethanol-based product that included phosphoric acid. These findings have major implications for the development of measures to reduce viral transmission in clinical practice., Lay Summary: Hepatitis E virus (HEV) showed a high level of resistance to alcohols and alcohol-based hand disinfectants. The addition of phosphoric acid to alcohol was essential for virucidal activity against HEV. This information should be used to guide improved hygiene measures for the prevention of HEV transmission., Competing Interests: Conflict of interest H.W.: Sponsored lectures/Consultant/Grants: Abbvie, Aligos, Altimmune, Biotest, BMS, BTG, Dicerna, Enanta, Gilead, Janssen, Merck/MSD, MYR GmbH, Roche, Vir Biotechnology. B.M.: Sponsored lectures/Consultant/Grants: AbbVie, Altona Diagnostics, Astellase, Fujirebio, Gilead, Medical Tribune, MSD, Roche Diagnostics, Roche. Stock or stock-options: BionTech. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: RNA detection in plasma/stool is the gold-standard for diagnosis of hepatitis E virus (HEV) infection. The impact of viral extraction methods on HEV RNA detection is poorly investigated., Methods: We determined the limit of detection of the RealStar HEV RT-PCR V2.0 Kit (altona Diagnostics, RS) utilizing 3 RNA extraction methods (COBAS ® AmpliPrep Total Nucleic Acid Isolation Kit, TNAi Roche; MagNA Pure 96 DNA, Viral NA SV Kit, MgP; QIAamp Viral RNA mini Kit Qiagen; VRK) in plasma and stool. The most sensitive method was evaluated in a total of 307 longitudinal samples of patients with HEV infection (acute = 18/chronic = 36) and compared to results with the former diagnostic standard of our centre (TNAi/FastTrack Diagnostic; FTD)., Results: The plasma-LOD was 49, 94 and 329 IU/mL for extraction with MgP, VRK and TNAi respectively. In stool, the LOD was 21 IU/mL, 528 IU/mL and indefinable for extraction with TNAi, VRK and MgP respectively. Utilizing longitudinal patient plasma samples, MgP/RS revealed 56 HEV RNA-positive samples in 158 negative samples as determined by TNAi/FTD. In stool, from 37 HEV negative samples (TNAi/FTD), 15 were positive with TNAi/RS. At end of treatment, 8 out of 27 chronically infected patients were RNA positive with MgP/RS, while classified negative with TNAi/FTD. A relapse occurred in 3 of these patients., Conclusion: Different methods for RNA extraction and quantification have a significant, compartment-specific impact on the sensitivity of HEV detection. Knowledge about the favourable combinations of extraction and quantification has important implications for diagnosis and patients receiving antiviral therapy., (© 2021 The Authors. Liver International published by John Wiley & Sons Ltd.)

Background: Hepatitis E virus (HEV) infection is an increasingly recognized cause of acute and chronic hepatitis in high-income countries and is the most frequent cause of acute viral hepatitis in many European countries. Appropriate tools to detect and quantify HEV RNA are needed. This study aimed to evaluate the performance of the Roche cobas® HEV assay and compare it with the Fast Track Diagnostics (FTD) Hepatitis E RNA assay., Methods: HEV viral load determination and lower limit of detection (LOD, defined as the lowest amount of viral copies that could be detected in 95 % of repeats) were assessed using a WHO standard dilution panel, testing 240 samples of various concentrations. Reproducibility was tested at three different concentration levels, for different genotypes, and with different sample types (serum, plasma) in 30 samples. Sample stability was analyzed after three freeze/thaw cycles in 25 samples., Results: Cobas HEV assay showed a strong linear relationship between log of HEV WHO dilution series and Ct values over the reportable range from 200-5000 IU/mL HEV RNA copies. The amplification efficiency was higher than 92 %. LOD was 22 IU/mL (95 % CI: 17.4-31.8) and reproducibility tests showed a 100 % nucleic acid test (NAT) reactivity of cobas HEV for WHO dilution series (range 200-5000 IU/mL, n = 90). Cobas HEV assay detected all different HEV genotypes from biobank samples irrespective of the sample type. NAT reactivity of cobas HEV was not affected by three freeze/thaw cycles., Conclusions: Roche cobas HEV assay is a powerful NAT tool in terms of robustness, reproducibility and linearity. It is a feasible alternative for high-volume testing., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background and Aims: Hepatitis E virus (HEV) is a major cause of acute viral hepatitis with >3 million symptomatic cases per year accounting for 70 000 HEV-related deaths. HEV-specific T-cell responses have been investigated against structural proteins expressed by open reading frames (ORF) 2 and 3. T-cell responses against non-structural HEV proteins encoded by ORF1 are hardly studied. The aim of this study was to determine HEV ORF1-specific T-cell responses in comparison to ORF2/3 in patients exposed to HEV., Methods: HEV-specific CD4 + and CD8 + T-cell responses against HEV genotype 3 were investigated in patients with acute and chronic hepatitis E as well as in HEV seropositive and seronegative individuals. HEV-specific T-cell responses were determined by proliferation and intracellular cytokine assay upon stimulation of PBMCs with HEV-specific overlapping peptide pools spanning the entire HEV genome. HEV-antigen was measured using an anti-HEV antigen-specific ELISA., Results: Broad HEV ORF1-specific T-cell responses were detected in patients with acute, resolved and chronic hepatitis E without distinct dominant regions. The magnitude and frequency in recognition of ORF1-specific T-cell responses were similar compared to responses against HEV ORF2/3. Longitudinal studies of HEV-specific T-cell responses displayed similar behaviour against structural and non-structural proteins. HEV-antigen levels were inversely correlated with HEV-specific T-cell responses., Conclusions: HEV-specific T-cell responses are detectable against the entire HEV genome including the non-structural proteins. HEV-specific T-cell responses are associated with control of HEV infection. These findings have implications for the design of HEV vaccines., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: Hepatitis E virus (HEV) infection can take chronic courses in immunocompromised patients potentially leading to liver cirrhosis and liver failure. Ribavirin (RBV) is currently the only treatment option for many patients, but treatment failure can occur which has been associated with the appearance of a distinct HEV polymerase mutant (G1634R). Here, we performed a detailed analysis of HEV viral intrahost evolution during chronic hepatitis E infections., Design: Illumina deep sequencing was performed for the detection of intrahost variation in the HEV genome of chronically infected patients. Novel polymerase mutants were investigated in vitro using state-of-the-art HEV cell culture models., Results: Together, these data revealed that (1) viral diversity differed markedly between patients but did not show major intraindividual short-term variations in untreated patients with chronic hepatitis E, (2) RBV therapy was associated with an increase in viral heterogeneity which was reversible when treatment was stopped, (3) the G1634R mutant was detectable as a minor population prior to therapy in patients who subsequently failed to achieve a sustained virological response to RBV therapy and (4) in addition to G1634R further dominant variants in the polymerase region emerged, impacting HEV replication efficiency in vitro., Conclusions: In summary, this first investigation of intrahost HEV population evolution indicates that RBV causes HEV mutagenesis in treated patients and that an emergence of distinct mutants within the viral population occurs during RBV therapy. We also suggest that next-generation sequencing could be useful to guide personalised antiviral strategies., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Hepatitis E is an inflammatory liver disease caused by infection with the hepatitis E virus (HEV). In tropical regions, HEV is highly endemic and predominantly mediated by HEV genotypes 1 and 2 with >3 million symptomatic cases per year and around 70 000 deaths. In Europe and America, the zoonotic HEV genotypes 3 and 4 have been reported with continues increasing new infections per year. So far, little is known about T-cell responses during acute HEV genotype 3 infection. Therefore, we did a comprehensive study investigating HEV-specific T-cell responses using genotypes 3- and 1-specific overlapping peptides. Additional cytokines and chemokines were measured in the plasma. In four patients, longitudinal studies were performed. Broad functional HEV-specific CD4(+) and CD8(+) T-cell responses were detectable in patients acutely infected with HEV genotype 3. Elevated of pro- and anti-inflammatory cytokine levels during acute HEV infection correlated with ALT levels. Memory HEV-specific T-cell responses were detectable up to >1.5 years upon infection. Importantly, cross-genotype HEV-specific T-cell responses (between genotypes 1 and 3) were measurable in all investigated patients. In conclusion, we could show for the first time HEV-specific T-cell responses during and after acute HEV genotype 3 infection. Our data of cross-genotype HEV-specific T-cell responses might suggest a potential role in cross-genotype-specific protection between HEV genotypes 1 and 3., (© 2016 John Wiley & Sons Ltd.)

Objectives: Cases of chronic hepatitis E virus (HEV) infection have been described in HIV-infected patients. There are several commercial anti-HEV assays, but anti-HEV seroprevalence rates differ largely depending on the assay used. The aim of this study was to (1) compare two commercial anti-HEV assays in a German cohort of HIV-positive individuals, and (2) determine whether HEV takes chronic courses in controlled HIV infection., Methods: 246 HIV patients were tested for both HEV RNA and HEV antibodies. All patients received antiretroviral therapy, if this was indicated, according to European guidelines. All but 19 individuals had CD4+ counts above 200/µl. Anti-HEV IgG was determined by two independent commercial assays (Wantai and MP)., Results: None of the patients tested HEV RNA positive. Anti-HEV IgG was detected more frequently by the Wantai assay (26%) than the MP assay (1.6%, p < 0.001). Patients born in Europe tested more frequently positive for anti-HEV (p = 0.047) than individuals from other regions. Increasing age but not CD4 count correlated with a higher likelihood of anti-HEV positivity (R = 0.313, p < 0.001)., Conclusions: About one quarter of HIV-infected patients show evidence of previous HEV contact. The risk of developing chronic HEV infection is very low in individuals receiving appropriate antiretroviral therapy. The large variability in HEV seroprevalence rates determined by different assays requires consideration for the diagnostic workup of HIV patients., (© 2015 S. Karger AG, Basel.)

We analyzed blood samples collected from 15 patients with chronic hepatitis E who were recipients of solid-organ transplants. All patients cleared the hepatitis E virus (HEV) except for 2 (nonresponders); 1 patient died. A G1634R mutation in viral polymerase was detected in the HEV RNA of the nonresponders; this mutation did not provide the virus with resistance to ribavirin in vitro. However, the mutant form of a subgenomic replicon of genotype 3 HEV replicated more efficiently in vitro than HEV without this mutation, and the same was true for infectious virus, including in competition assays. Similar results were obtained for genotype 1 HEV. The G1634R mutation therefore appears to increase the replicative capacity of HEV in the human liver and hence reduce the efficacy of ribavirin., (Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Objective: Persistent hepatitis E virus (HEV) infections have been described in various transplant cohorts. However, the frequency and the course of HEV infection in lung transplant recipients (Lu-Tr) are not well defined., Methods: We retrospectively analyzed serum from 95 Lu-Tr for HEV RNA and anti-HEV immunoglobulin-G (IgG) (with the MP assay). Anti-HEV seroprevalence was compared to that of 537 healthy individuals. Prospective HEV screening was subsequently initiated in Lu-Tr., Results: Elevated liver enzymes were observed in 44/95 (46.3%) patients. Anti-HEV IgG was present in 5/95 patients (5.3%), revealing a slightly higher prevalence compared to controls (2%, 11/537; P = 0.07). Chronic HEV infection with detectable viral replication was confirmed by polymerase chain reaction in 3 (3.2%) patients, all of whom demonstrated clinical and biochemical features of active liver disease (maximum alanine aminotransferase [ALTmax ] 89, 215, and 270 IU/L, respectively). One patient had died from multi-organ failure in combination with liver cirrhosis before HEV diagnosis. Two additional patients with chronic hepatitis E were identified during prospective screening (ALTmax 359 and 318 IU/L). All patients still alive commenced ribavirin therapy for 5 months, with dose adjustment (400-600 mg/day) according to renal function and hemoglobin level. Sustained resolution of HEV infection occurred in 2 patients. One patient is still under treatment, and the fourth died from graft failure considered unrelated to ribavirin therapy., Conclusion: Chronic hepatitis E should be considered in the differential diagnosis of elevated liver enzymes, which are commonly seen in Lu-Tr. We observed 1 case of end-stage liver cirrhosis and death in an HEV-infected subject, who was not treated with ribavirin. Given this potentially devastating consequence, ribavirin therapy of persistent HEV infection appears to be acceptably safe and effective in Lu-Tr. However, larger prospective studies are warranted., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Chronic courses of hepatitis E virus (HEV) infections have been described in immunosuppressed patients. We aimed to study the role of HEV infections in heart transplant recipients (HTR). 274 HTR were prospectively screened for HEV infection using an anti-HEV-IgG ELISA and HEV-PCR. In addition, 137 patients undergoing cardiac surgery (non-HTR) and 537 healthy subjects were studied cross-sectionally. The anti-HEV-IgG seroprevalence was 11% in HTR, 7% in non-HTR and 2% in healthy controls (HTR vs. healthy controls p<0.0001; non-HTR vs. healthy controls p<0.01). Anti-HEV tested positive in 4.0% in control cohorts of other immunocompromised patients (n = 474). Four HTR (1.5%) were chronically infected with HEV as shown by HEV-PCR and all four patients had liver transaminases of >200 IU/L and histological or clinical evidence of advanced liver disease. In three patients ribavirin treatment was successful with a sustained biochemical and virological response while treatment failed in one cirrhotic patient after ribavirin dose reduction. Heart transplant recipients and patients undergoing cardiac surgery have an increased risk for HEV infections. Chronic hepatitis E may explain elevated liver enzymes in heart transplant recipients. Treatment of HEV infection with ribavirin is effective but the optimal dose and duration of ribavirin therapy remains to be determined., (© Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Hepatitis E virus (HEV) infection is usually self-limited but may lead to acute hepatitis and rarely to fulminant hepatic failure. Persistent HEV infections have recently been described in organ transplant recipients receiving immunosuppressive medications, suggesting that HEV is controlled by adaptive immune responses. However, only few studies have investigated HEV-specific T-cell responses and immune correlates for the failure to clear HEV infection have not been established so far. We investigated T-cell responses against HEV in 38 subjects including anti-HEV-positive (exposed, n = 9) and anti-HEV-negative (n = 10) healthy controls, 12 anti-HEV-positive but HEV RNA-negative organ transplant recipients, and seven transplant recipients with chronic hepatitis E. Proliferation as well as cytokine production of CD4+ and CD8+ T cells was studied after stimulation with overlapping peptides spanning all proteins encoded by HEV-open reading frame (ORF)2 and HEV-ORF3. We show that (1) strong and multispecific HEV-specific T-cell responses are present in exposed healthy controls, and to a lesser extent also in recovered patients after transplantation; (2) that these responses are absent in patients with chronic hepatitis E but become detectable after viral clearance; and (3) that HEV-specific T-cell responses can be restored in vitro by blocking the PD-1 or CTLA-4 pathways. However, a combination of PD-1 and CTLA-4 blockade had no synergistic effects. We conclude that chronic hepatitis E is associated with impaired HEV-specific T-cell responses and suggest that enhancing adaptive cellular immunity against HEV might prevent persistent HEV infections., (Copyright © 2011 American Association for the Study of Liver Diseases.)

Cases of chronic hepatitis E have been described in patients after kidney and liver transplantation. In addition, hepatitis E virus (HEV) reactivation was reported after hematopoietic stem cell transplantation (HSCT). We here evaluated if HEV infection might explain elevated liver enzymes in a well selected cohort of allogeneic HSCT patients with biochemical evidence of hepatitis (n = 52). Of note, none of the subjects tested positive for HEV RNA, including 2 HSCT patients who had been infected with HEV already before transplantation. Thus, both chronic courses of HEV infections and HEV reactivations seem to be rather rare events in HSCT patients in a non-endemic country., (© 2011 John Wiley & Sons A/S.)

Increased frequencies of HEV infections have been reported in several industrialized countries. We suggest that this finding might be explained by a better awareness of the disease and not by an increased incidence. Although reported HEV infections increased more than 6-fold in Germany in recent years, the seroprevalence remained unchanged (2 %)., (© Georg Thieme Verlag KG Stuttgart · New York.)

Hepatitis E virus (HEV) infection induces self-limiting liver disease in immunocompetent individuals. Cases of chronic hepatitis E have recently been identified in organ transplant recipients. We questioned if chronic hepatitis E plays a role in graft hepatitis after liver transplantation in a low endemic area. Two hundred twenty-six liver transplant recipients, 129 nontransplanted patients with chronic liver disease, and 108 healthy controls were tested for HEV antibodies. HEV RNA was investigated in all sera from transplanted patients. HEV antibodies were detected in 1 healthy control (1%), 4 patients with chronic liver disease (3%), and 10 liver transplant recipients (4%). Three liver transplant patients also tested positive for HEV RNA. Two of them developed persistent viremia with HEV genotype 3. The patients were anti-HEV immunoglobulin G-negative and HEV RNA-negative before transplantation and had an episode of acute hepatitis 5 or 7 months after transplantation, which led to advanced liver fibrosis after 22 months in 1 patient. Seroconversion to anti-HEV occurred not before 4 months after the first detection of HEV RNA. The possibility of reverse zoonotic transmission was experimentally confirmed by the infection of 5 pigs with a patient's serum. The pigs showed histological inflammation in the liver, and HEV RNA was detectable in different organs, including muscle. In conclusion, the prevalence of HEV infection in Central European liver transplant recipients is low; however, chronic hepatitis E may occur and needs to be considered in the differential diagnosis of graft hepatitis. The diagnosis of HEV infection should be based on HEV RNA determination in immunosuppressed patients. We suggest that immunocompromised individuals should avoid eating uncooked meat and contact with possibly HEV-infected animals.