Hepatitis E Virus Infection-Immune Responses to an Underestimated Global Threat

Infection with the hepatitis E virus (HEV) is one of the main ubiquitous causes for developing an acute hepatitis. Moreover, chronification plays a predominant role in immunocompromised patients such as transplant recipients with more frequent severe courses. Unfortunately, besides reduction of immunosuppression and off-label use of ribavirin or pegylated interferon alfa, there is currently no specific anti-viral treatment to prevent disease progression. So far, research on involved immune mechanisms induced by HEV is limited. It is very difficult to collect clinical samples especially from the early phase of infection since this is often asymptomatic. Nevertheless, it is certain that the outcome of HEV-infected patients correlates with the strength of the proceeding immune response. Several lymphoid cells have been identified in contributing either to disease progression or achieving sustained virologic response. In particular, a sufficient immune control by both CD4⁺ and CD8⁺ T cells is necessary to prevent chronic viral replication. Especially the mechanisms underlying fulminant courses are poorly understood. However, liver biopsies indicate the involvement of cytotoxic T cells in liver damage. In this review, we aimed to highlight different parts of the lymphoid immune response against HEV and point out questions that remain unanswered regarding this underestimated global threat.

Immunogenicity and Antigenicity of Rabbit Hepatitis E Virus-Like Particles Produced by Recombinant Baculoviruses

Rabbit hepatitis E virus (HEV) is a novel HEV belonging to genotype 3 (HEV-3) in the Orthohepevirus A species of the genus Hepevirus, family Hepeviridae. Rabbit HEV was originally isolated from rabbits and found to cause zoonotic infection. Although rabbit HEV can be successfully grown in culture with several cell lines, including the human carcinoma cell line PLC/PRF/5, it is difficult to obtain the large amounts of viral antigen required for diagnosis and vaccine development. In this study, we expressed N-terminal 13 and 111 aa-truncated rabbit HEV ORF2 proteins using recombinant baculoviruses and obtained two types of virus-like particles (VLPs), RnVLPs and RsVLPs with ~35 and 24 nm diameter, respectively. Anti-rabbit HEV IgG antibodies were induced in high titer by immunizing rabbits with RnVLPs or RsVLPs. The antibody secretion in the serum persisted more than three years. RsVLPs showed stronger antigenic cross-reactivity against HEV-1, HEV-3 and HEV-4 than rat HEV. Moreover, anti-RsVLPs antibodies neutralized not only the cognate virus but also HEV-1, HEV-3 and HEV-4 ex vivo, indicating that rabbit HEV had the same serotype as human HEVs. In contrast, the antibody did not block rat HEV infection, demonstrating that rat HEV belonged to a different serotype. Animal experiments indicated that immunization with either RnVLPs or RsVLPs completely protected the rabbits from challenge by rabbit HEV, suggesting that the VLPs are candidates for rabbit HEV vaccine development.

Hepatitis E virus persists in the ejaculate of chronically infected men

BACKGROUND & AIMS

Hepatitis E virus (HEV) infections are prevalent worldwide. Various viruses have been detected in the ejaculate and can outlast the duration of viremia, indicating replication beyond the blood-testis barrier. HEV replication in diverse organs, however, is still widely misunderstood. We aimed to determine the occurrence, features and morphology of HEV in the ejaculate.

METHODS

The presence of HEV in testis was assessed in 12 experimentally HEV-genotype 3-infected pigs. We further tested ejaculate, urine, stool and blood from 3 chronically HEV genotype 3-infected patients and 6 immunocompetent patients with acute HEV infection by HEV-PCR. Morphology and genomic characterization of HEV particles from various human compartments were determined by HEV-PCR, density gradient measurement, immune-electron microscopy and genomic sequencing.

RESULTS

In 2 of the 3 chronically HEV-infected patients, we observed HEV-RNA (genotype 3c) in seminal plasma and semen with viral loads >2 logs higher than in the serum. Genomic sequencing showed significant differences between viral strains in the ejaculate compared to stool. Under ribavirin-treatment, HEV shedding in the ejaculate continued for >9 months following the end of viremia. Density gradient measurement and immune-electron microscopy characterized (enveloped) HEV particles in the ejaculate as intact.

CONCLUSIONS

The male reproductive system was shown to be a niche of HEV persistence in chronic HEV infection. Surprisingly, sequence analysis revealed distinct genetic HEV variants in the stool and serum, originating from the liver, compared to variants in the ejaculate originating from the male reproductive system. Enveloped HEV particles in the ejaculate did not morphologically differ from serum-derived HEV particles.

LAY SUMMARY

Enveloped hepatitis E virus particles could be identified by PCR and electron microscopy in the ejaculate of immunosuppressed chronically infected patients, but not in immunocompetent experimentally infected pigs or in patients with acute self-limiting hepatitis E.

Emerging Hepatotropic Viruses in Cats: A Brief Review

The possible role of viruses in feline liver disease has long remained neglected. However, in 2018, an analogue of human hepatitis B virus was identified in cats. Moreover, antibodies for human hepatitis E have been detected consistently at various prevalence rates in cats. Although the correlation between these viruses and the liver injury in cats must be clarified, hepatotropic viruses might represent an increasing risk for feline and public health.

First molecular characterization of the hepatitis E virus in humans in Cameroon: Confirmation of the HEV outbreak in Touboro, North-Cameroon

Hepatitis E virus (HEV) is a major causative agent of acute viral hepatitis in many regions of the world including Africa. In Cameroon, there is no published molecular study on HEV in humans. However, based on serological assays, the first outbreak of HEV was detected in North-Cameroon. The objective of this study was to determine the molecular characterization of HEV that circulated during this period. A retrospective study design was used to select serum samples among those collected during the outbreak period. immunoglobulin M positive samples available in sufficient volumes to amplify HEV RNA were selected. RNA was extracted and then amplified by a real-time reverse transcription polymerase chain reaction (real time RT-PCR) assay, followed by a nested reverse transcription polymerase chain reaction (nested RT-PCR) assay for sequencing and phylogenetic analysis. Overall, 24 samples were selected and HEV RNA was amplified by real-time RT-PCR in 20 samples. Amongst these, 12 samples were positive for HEV RNA by nested RT-PCR and yielded good sequencing products. Phylogenetic analysis showed that 10 samples clustered with HEV genotype 1 (subtype 1e) and two samples clustered with HEV genotype 3 (subtype 3f). This study fills the gap of knowledge on the molecular epidemiology of HEV in Cameroon and confirms the first report of the hepatitis E outbreak in North-Cameroon.

Serological and molecular prevalence of hepatitis E virus among blood donors from Uruguay

Hepatitis E virus (HEV) infection is considered a neglected disease of major concern in developed countries. Clinically, HEV occurs as an acute and self-limited disease, though chronic cases mostly associated to HEV-3 are now being commonly reported in immunocompromised individuals and solid organ transplant recipients. Transmission of HEV through blood and derivatives have been increasingly described in the last years, highlighting the importance of including this agent on the screening programs. Since 2010 both acute and chronic hepatitis E cases have been frequently reported in Uruguay. However, updated prevalence data among different population groups are lacking and HEV is not currently screened in blood banks. Herein, we report a seroprevalence and molecular survey of HEV in 400 plasma samples from blood donors. Overall, our results showed an HEV seroprevalence rate of 10% (40/400); almost 10-fold higher than 20 years ago. Total anti-HEV immunoglobulin antibodies were found to increase with age. Moreover, we reported an RNA detection rate of at least 0.75%, and two strains were sequenced. Phylogenetic analysis grouped them with human and swine HEV-3 strains from Uruguay. Data presented here should prompt public health policies of HEV screening in blood banks to minimize the risk of transfusion-transmitted hepatitis E.

Hepatitis E virus infection and waste pickers: A case-control seroprevalence study

Whether waste pickers are a risk group for hepatitis E virus (HEV) infection is largely unknown. This study aimed to determine the association between HEV exposure and the occupation of waste pickers and the work characteristics of waste pickers. An age-and gender-matched case-control seroprevalence study of 86 waste pickers and 86 control subjects of the general population was performed. We determined anti-HEV IgG antibodies in sera of cases and controls using a commercially available enzyme-linked immunoassay. The McNemar's test was used to assess the association between HEV seropositivity and the occupation of waste picker. The association between HEV seropositivity and work characteristics of waste pickers was assessed by bivariate and logistic regression analyses. Anti-HEV IgG antibodies were detected in 14 (16.3%) of the 86 waste pickers and in 8 (9.3%) of the 86 control subjects (McNemar's pair test: odds ratio (OR) = 13.0; 95% confidence interval (CI): 0.73-230.77; p = .02). Bivariate analysis showed that HEV exposure was associated with an ill status (p = .01) and reflexes impairment (p = .009). Logistic regression analysis showed that HEV seropositivity was associated with increasing age (OR = 6.52; 95% CI: 1.95-21.78; p = .002) and raising pigs (OR = 12.01; 95% CI: 1.48-97.26; p = .02). This is the first age- and gender-matched case-control study on the association between HEV infection and the occupation of waste picker. Waste pickers represent a risk group for HEV infection. Factors associated with HEV seropositivity found in this study may help in the design of optimal planning to avoid HEV infection.

Prevalence of hepatitis E virus in children from Northeast of Argentina

The aim of this study was to assess the prevalence of hepatitis E virus (HEV) in a young population from the Northeast region of Argentina. Four hundred and twelve patients under 18 years old, from rural areas of Chaco Province, were tested for anti-HEV immunoglobulin G (IgG) using enzyme-linked immunosorbent assay. Anti-HEV IgG antibodies were detected in 7 out of 412 patients, accounting for an overall 1.7% prevalence. HEV infection in developing countries is associated to lack of clean drinking water. Consequently, the seroprevalence observed in children in rural areas of Chaco, Argentina, where the access to tap water is less than 15%, was unexpectedly low.

An outbreak of hepatitis E in Yavatmal, India, 2019

Hepatitis E, a public health concern in developing countries, frequently presents in epidemic, as well as in sporadic forms. This study investigated an outbreak of viral hepatitis at Yavatmal, Maharashtra, India in March 2019. Blood samples from 10 patients were received at Indian Council of Medical Research-National Institute of Virology, Pune to test for the presence of enterically transmitted hepatitis viruses. Subsequently, 49 suspected cases were screened for anti-hepatitis E virus (HEV)/hepatitis A virus (HAV) immunoglobulin M and immunoglobulin G (IgG) antibodies, alanine amino-transferase levels and HEV RNA. Water samples were screened for HEV and HAV RNA followed by phylogenetic analysis. Overall 32 of 49 (65.3%) suspected cases had recent acute HEV infection, while dual infection with HAV was noted in one case (2.04%). Forty-eight of 49 suspected cases were positive for anti-HAV IgG antibodies indicative of previously acquired immunity against HAV. Water samples had evidence of HEV contamination as detected by reverse transcription-polymerase chain reaction. Sequencing of HEV RNA from both patients (n = 2) and water samples (n = 5) indicated HEV genotype 1 to be the etiological agent of this outbreak. Serological and molecular evidence confirmed HEV as the etiology. Mixing of contaminated drain water with the domestic water supply may have triggered this outbreak. Subsequent changing of the defaulted water pipelines and its segregation from drain pipelines by the health authorities resulted in progressive decline of this outbreak. Despite the limitations, periodic surveillance of HEV exposure pattern and reporting of small outbreaks would supplement to the global disease burden data of hepatitis E.

Effector memory CD8 T cell response elicits Hepatitis E Virus genotype 3 pathogenesis in the elderly

Genotype 3 Hepatitis E virus (HEV-3) is an emerging threat for aging population. More than one third of older infected patients develops clinical symptoms with severe liver damage, while others remain asymptomatic. The origin of this discrepancy is still elusive although HEV-3 pathogenesis appears to be immune-mediated. Therefore, we investigated the role of CD8 T cells in the outcome of the infection in immunocompetent elderly subjects. We enrolled twenty two HEV-3-infected patients displaying similar viral determinants and fifteen healthy donors. Among the infected group, sixteen patients experienced clinical symptoms related to liver disease while six remained asymptomatic. Here we report that symptomatic infection is characterized by an expansion of highly activated effector memory CD8 T (EM) cells, regardless of antigen specificity. This robust activation is associated with key features of early T cell exhaustion including a loss in polyfunctional type-1 cytokine production and partial commitment to type-2 cells. In addition, we show that bystander activation of EM cells seems to be dependent on the inflammatory cytokines IL-15 and IL-18, and is supported by an upregulation of the activating receptor NKG2D and an exuberant expression of T-Bet and T-Bet-regulated genes including granzyme B and CXCR3. We also show that the inflammatory chemokines CXCL9-10 are increased in symptomatic patients thereby fostering the recruitment of highly cytotoxic EM cells into the liver in a CXCR3-dependent manner. Finally, we find that the EM-biased immune response returns to homeostasis following viral clearance and disease resolution, further linking the EM cells response to viral burden. Conversely, asymptomatic patients are endowed with low-to-moderate EM cell response. In summary, our findings define immune correlates that contribute to HEV-3 pathogenesis and emphasize the central role of EM cells in governing the outcome of the infection.

The outcome of Genotype 3 Hepatitis E virus (HEV-3) infection differs among the elderly. Some patients develop severe forms of Hepatitis E while others remain asymptomatic. Nonetheless, parameters which can lead to severe versus silent infection are largely unknown. Therefore, we investigated immunological features of CD8 T cells in infected patients (aged ≥55) with similar viral determinants but distinct clinical outcomes. We show that drastic phenotypic changes were specifically observed within the effector memory (EM) compartment. Compared to asymptomatic patients, symptomatic ones display a strong activation of both HEV-3-specific and -nonspecific EM CD8 T cells associated with qualitative and quantitative alterations in cytokine production. In addition, EM cells are endowed with high cytotoxic capacity and have the ability to rapidly migrate to the liver. Finally, we report that the inflammatory response to HEV-3 infection shape EM cell activation and function in symptomatic elderly patients. In summary, our results present the first report demonstrating that the nature and the magnitude of EM CD8 T cell response play an important role in the outcome of HEV-3 infection in the elderly.

The Burden of Hepatitis E Infection in Chronic Liver Diseases in Croatia

In patients with chronic liver disease (CLD), hepatitis E virus (HEV) may lead to decompensation and death. We tested 438 CLD patients (71.0% male; age 23-84 years) for HEV-IgG antibodies. Reactive samples were tested for HEV-IgM antibodies using ELISA. IgM positive samples were tested for HEV RNA using RT-PCR. HEV-IgG antibodies were found in 15.1% of patients, whereas 4.5% of IgG positive patients had detectable IgM antibodies. Not a single patient tested HEV RNA positive. Seroprevalence increased with age, from 9.7% (<45 years) to 17.4% (>60 years, p = 0.368). There was no difference in HEV-IgG seropositivity related to gender, level of education, geographic region, area of residence, liver disease, or hepatocellular carcinoma presence. Previous exposure to HEV was detected in 15.1% of patients, corresponding with the data from other endemic European regions. Despite the high local exposure, we did not find any evidence of acute or chronic hepatitis E among CLD patients.

Antibodies Against Hepatitis E Virus (HEV) in European Moose and White-Tailed Deer in Finland

The main animal reservoirs of zoonotic hepatitis E virus (HEV) are domestic pigs and wild boars, but HEV also infects cervids. In this study, we estimated the prevalence of HEV in Finnish cervid species that are commonly hunted for human consumption. We investigated sera from 342 European moose (Alces alces), 70 white-tailed deer (Odocoileus virginianus), and 12 European roe deer (Capreolus capreolus). The samples had been collected from legally hunted animals from different districts of Finland during 2008-2009. We analysed the samples for total anti-HEV antibodies using a double-sandwich ELISA assay. Seropositive sera were analysed with RT-qPCR for HEV RNA. HEV seroprevalence was 9.1% (31/342) in moose and 1.4% (1/70) in white-tailed deer. None of the European roe deer were HEV seropositive (0/12). No HEV RNA was detected from samples of seropositive animals. HEV seropositive moose were detected in all districts. Statistically, HEV seroprevalence in moose was significantly higher (p < 0.05) in the North-East area compared to the South-West area. The highest HEV seroprevalence (20.0%) in district level was more than six times higher than the lowest (3.1%). We demonstrated the presence of total anti-HEV antibodies in European moose and white-tailed deer in Finland. Our results suggest that HEV is circulating among the moose population. Infections may occur also in white-tailed deer. We were the first to report a HEV seropositive white-tailed deer from Europe. Further studies are needed to demonstrate the HEV genotypes in cervids in Finland and to evaluate the importance of the findings in relation to food safety.

A plant-based transient expression system for the rapid production of highly immunogenic Hepatitis E virus-like particles

OBJECTIVE

Hepatitis E virus (HEV) infection is a major cause of acute hepatitis worldwide. The aim of the study is the development of plant expression system for the production of virus-like particles formed by HEV capsid and the characterization of their immunogenicity.

RESULTS

Open reading frame (ORF) 2 encodes the viral capsid protein and possesses candidate for vaccine production. In this study, we used truncated genotype 3 HEV ORF 2 consisting of aa residues 110 to 610. The recombinant protein was expressed in Nicotiana benthamiana plants using the self-replicating potato virus X-based vector pEff up to 10% of the soluble protein fraction. The yield of HEV 110-610 after purification was 150-200 µg per 1 g of green leaf biomass. The recombinant protein formed nanosized virus-like particles. The immunization of mice with plant-produced HEV 110-610 protein induced high levels of HEV-specific serum antibodies.

CONCLUSIONS

HEV ORF 2 (110-610 aa) can be used as candidate for the development of a plant-produced vaccine against Hepatitis E.

Disseminated inflammation of the central nervous system associated with acute hepatitis E: a case report

BACKGROUND

Hepatitis E infection affects over 20 million people worldwide. Reports of neurological manifestations are largely limited to the peripheral nervous system. We report a middle-aged genotype 3c male patient with acute hepatitis E virus (HEV) infection and severe neurological deficits with evidence of multiple disseminated inflammatory lesions of the central nervous system.

CASE PRESENTATION

A 42-year-old male patient presented to our emergency department with musculoskeletal weakness, bladder and bowel retention, blurred vision and ascending hypoesthesia up to the level of T8. Serology showed elevated liver enzymes and positive IgM-titers of hepatitis E. Analysis of cerebrospinal fluid (CSF) showed mild pleocytosis and normal levels of glucose, lactate and protein. HEV-RNA-copies were detected in the CSF and stool. Within 3 days after admission the patient became paraplegic, had complete visual loss and absent pupillary reflexes. MRI showed inflammatory demyelination of the optic nerve sheaths, multiple subcortical brain regions and the spinal cord. Electrophysiology revealed axonal damage of the peroneal nerve on both sides with absent F-waves. Treatment was performed with methylprednisolone, two cycles of plasma exchange (PLEX), one cycle of intravenous immunoglobulins (IVIG) and ribavirin which was used off-label. Liver enzymes normalized after 1 week and serology was negative for HEV-RNA after 3 weeks. Follow-up MRI showed progressive demyelination and new leptomeningeal enhancement at the thoracic spine and cauda equina 4 weeks after admission. Four months later, after rehabilitation was completed, repeated MRI showed gliotic transformation of the spinal cord without signs of an active inflammation. Treatment with rituximab was initiated. The patient remained paraplegic and hypoesthesia had ascended up to T5. Nevertheless, he regained full vision.

CONCLUSIONS

Our case indicates a possible association of acute HEV infection with widespread disseminated central nervous system inflammation. Up to now, no specific drugs have been approved for the treatment of acute HEV infection. We treated our patient off-label with ribavirin and escalated immunomodulatory therapy considering clinical progression and the possibility of an autoimmune response targeting nerve cell structures. While response to treatment was rather limited in our case, detection of HEV in patients with acute neurological deficits might help optimize individual treatment strategies.

Experimental infection of hepatitis E virus induces pancreatic necroptosis in miniature pigs

Infection by hepatitis E virus (HEV) via the oral route causes acute hepatitis. Extra-hepatic manifestations of HEV infection may stem from various causes; however, its distribution in organs such as the liver, as well as the mechanisms underlying HEV-induced cell injury, remain unclear. The objective of this study was to determine the chronological distribution of HEV in various tissues of HEV-challenged miniature pigs and to investigate the mechanisms underlying HEV-induced cell death in the pancreas and liver. Virological and serological analyses were performed on blood and faecal samples. Histopathology of the liver and extra-hepatic tissues was analysed. Cell death pathways and immune cell characterisation in inflammatory lesions were analysed using immunohistochemistry. The liver and pancreas displayed inflammation and cellular injury, and a large amount of HEV was observed in the lesions. The liver was infiltrated by T and natural killer cells. HEV was identified in all organs except the heart, and was associated with immune cells. Although the liver and the pancreas strongly expressed TNF-α and TRAIL, TUNEL assay results were negative. RIP3 and pMLKL were expressed in the pancreas. RIP3, but not pMLKL, was expressed in the liver. Pancreatitis induced in HEV-infected miniature pigs is associated with necroptosis.

Unexpected long-lasting anti-HEV IgM positivity: Is HEV antigen a better serological marker for hepatitis E infection diagnosis?

Hepatitis E virus (HEV) is the leading cause of acute hepatitis worldwide. The minimum criterion for diagnosis of acute infection is detection of anti-HEV antibodies, although there are scant data on IgM duration. Our aim was to assess the persistence of HEV markers after acute self-limited hepatitis E. HEV serological tests (IgM by Mikrogen and Wantai and HEV-Ag) and HEV RNA were carried out in two cohorts: (a) patients with prior acute hepatitis E (ALT >10 x ULN plus positive IgM ± HEV RNA) currently self-limited and (b) 50 blood donors with positive HEV RNA. Among 25 cases of prior acute hepatitis E, after a median follow-up of 34 months, all presented undetectable HEV RNA. However, anti-HEV IgM remained detectable in 14 (56%) by Mikrogen, 6 (24%) by Wantai and none for HEV-Ag. Anti-HEV IgM tested positive in 80%-100% within the second year and 17%-42% over 3 years later, by Wantai and Mikrogen, respectively. Among HEV RNA-positive donors, 12 (25%) tested positive for either IgM by Mikrogen or Wantai, 9 (18%) for both and 18 (36%) for HEV-Ag. HEV-Ag positivity was more likely as HEV RNA was higher (14% if <2.2 log IU/mL; 64% if RNA ≥ 3.7). Overall, HEV-Ag performed best, with a positive predictive value of 100% and diagnostic accuracy of 57%. Anti-HEV IgM exhibited unexpectedly long persistence after a self-limited acute hepatitis E. HEV-Ag had the best performance and could be especially useful in settings where HEV RNA is not available.

Seroepidemiology of hepatitis E in patients on haemodialysis in Croatia

PURPOSE

Data on the seroprevalence of hepatitis E virus (HEV) in heamodialysis (HD) patients are conflicting, ranging from 0 to 44%. The aim of this study was to determine the HEV seroprevalence and risk factors among HD patients in Croatia.

METHODS

A total of 394 HD patients from six medical facilities in five Croatian cities (three sites in the continental and three sites in the coastal region) were tested for HEV IgM/IgG antibodies using an enzyme-linked immunosorbent assay. Additionally, all samples were tested for HEV RNA by RT-PCR. Sociodemographic data and risk factors were collected using a questionnaire.

RESULTS

HEV IgG antibodies were detected in 110 (27.9%) patients. The seroprevalence varied significantly between dialysis centres, ranging from 5.2 to 43.4% (p = 0.001). HEV IgM antibodies were found in 0.04% of IgG positive patients. All patients tested negative for HEV RNA. Factors associated with HEV IgG seropositivity were age > 60 years (OR 8.17; 95% CI 1.08-62.14), living in the continental parts of the country (OR 2.58; 95% CI 1.55-4.30), and transfusion of blood products (OR 1.66; 95% CI 1.01-2.73). After adjusting for age and gender, patients from continental regions had higher odds of HEV seropositivity compared to patients from coastal regions (OR 2.88; 95% CI 1.71-4.85) and those who had RBC transfusions (OR 1.70, 95% CI 1.02-2.69) compared to those who did not.

CONCLUSION

The study showed a high HEV seropositivity among HD patients in Croatia, with significant variations between geographical regions. Continental area of residence and RBC transfusion were the most significant risk factors for HEV seropositivity. Due to the high seroprevalence, routine HEV screening among HD patients, especially in transplant candidates should be considered.

Establishment of a Highly Sensitive Assay for Detection of Hepatitis E Virus-Specific Immunoglobulins

Hepatitis E, a liver disease caused by infection with the hepatitis E virus (HEV), is a worldwide emerging disease. The diagnosis is based on the detection of viral RNA and of HEV-specific immunoglobulins (Ig). For the latter, various assays are commercially available but still lack harmonization. In this study, a Luminex-based multiplex serological assay was established that measures the presence of total IgG, IgA, and IgM antibodies, targeting a short peptide derived from the viral E2 protein. For the validation, 160 serum samples with a known HEV serostatus were used to determine the assay cutoff and accuracy. Thereby, HEV IgG- and RNA-positive sera were identified with a sensitivity of 100% and a specificity of 98% (95% confidence interval [CI], 94% to 100%). Application of the assay by retesting 514 serum samples previously characterized with different HEV-IgG or total antibody tests revealed a high level of agreement between the assays (Cohen's kappa, 0.58 to 0.99). The established method is highly sensitive and specific and can be easily implemented in a multiplex format to facilitate rapid differential diagnostics with a few microliters of sample input.

Prophylactic Hepatitis E Vaccines: Antigenic Analysis and Serological Evaluation

Hepatitis E virus (HEV) infection causes sporadic outbreaks of acute hepatitis worldwide. HEV was previously considered to be restricted to resource-limited countries with poor sanitary conditions, but increasing evidence implies that HEV is also a public health problem in developed countries and regions. Fortunately, several vaccine candidates based on virus-like particles (VLPs) have progressed into the clinical development stage, and one of them has been approved in China. This review provides an overview of the current HEV vaccine pipeline and future development with the emphasis on defining the critical quality attributes for the well-characterized vaccines. The presence of clinically relevant epitopes on the VLP surface is critical for eliciting functional antibodies against HEV infection, which is the key to the mechanism of action of the prophylactic vaccines against viral infections. Therefore, the epitope-specific immunochemical assays based on monoclonal antibodies (mAbs) for HEV vaccine antigen are critical methods in the toolbox for epitope characterization and for in vitro potency assessment. Moreover, serological evaluation methods after immunization are also discussed as biomarkers for clinical performance. The vaccine efficacy surrogate assays are critical in the preclinical and clinical stages of VLP-based vaccine development.

Hepatitis E outbreak in Jaipur due to Genotype IA

Purpose

Suddenly, many cases of fever with jaundice were reported from Sodala area at Jaipur. This outbreak of acute hepatitis at Jaipur Rajasthan was investigated for aetiology and subsequent phylogenetic analysis.

Methods

Blood samples were collected from 106 symptomatic patients of acute hepatitis and 39 pregnant females (with or without symptoms of hepatitis) during an outbreak at Jaipur. The samples were tested for hepatitis A virus (HAV) and hepatitis E virus (HEV) by serological and molecular methods (polymerase chain reaction [PCR]). Sequencing of nested PCR product was done for phylogenetic analysis. Hepatitis B surface antigen (HBs antigen), anti-hepatitis C virus (HCV), anti-Leptospira and anti-scrub typhus IgM enzyme-linked immunosorbent assay (ELISA) was done for patients negative for HEV and HAV.

Results

Among 106 symptomatic patients, HEV IgM was positive in 84/106 (79.2%) patients and HEV RNA in 72/106 (67.9%) patients. Among pregnant women, 6/39 (15.4%) were HEV IgM positive and 5/39 (12.8%) for HEV RNA. One (2.5%) pregnant woman died due to hepatitis. All the isolates belonged to genotype 1A of HEV. All HAV, HEV-negative samples were negative for HBs antigen, HCV antibody, Leptospira and scrub typhus IgM ELISA.

Conclusion

The outbreak was due to HEV genotype 1A. The municipal water supply was contaminated and sanitary conditions and waste disposal were poor in the area. Boiling of drinking water, fixing the water supply pipes and frequent hand washing helped in controlling the outbreak.

Circulating interferon-λ3 and post-vaccination antibodies against the surface antigen of hepatitis B virus in hemodialysis patients exposed to hepatitis E virus

Responsiveness to the hepatitis B virus (HBV) vaccination in hemodialysis (HD) patients who had been exposed to the hepatitis E virus (HEV) and persistently generate antibodies against HEV remains unknown. Interferon (IFN)-λ3 positively correlates with the surface HBV antibodies (anti-HBs) in both healthy and HD subjects. We aimed to show whether HD patients differ in circulating IFN-λ3 and vaccine-induced anti-HBs titers concerning natural HEV immunization. HBV/HCV negative HD patients (31 HEV IgG positive, 45 HEV negative), HBV vaccinated and receiving booster doses as needed, had been tested for anti-HBs titers (CMIA) and IFN-λ3 concentrations (ELISA) in the blood collected before a dialysis session. There were no differences in circulating IFN-λ3 and anti-HBs titers between both groups. In responders to the HBV vaccine, there was a positive correlation between plasma IFN-λ3 levels and anti-HBs titers (r = 0.505, adjusted P = 0.01 in HEV exposed subjects; r = 0.523, adjusted P = 0.001 in controls). HEV past infection does not attenuate post-vaccination anti-HBs generation and does not influence a correlation between circulating IFN-λ3 levels and anti-HBs titers.

Evaluation of the protective effects of a nanogel-based vaccine against rabbit hepatitis E virus

Infection with hepatitis E virus (HEV) has raised serious public health concerns worldwide. In this study, a nanogel-based vaccine encapsulating the capsid protein of rabbit HEV was developed and its protective efficacy was compared with a subunit vaccine. A total of 23 rabbits were divided into 5 groups: (1) negative control (n = 4), (2) positive control (n = 4), (3) nanogel control (n = 5), (4) nanogel vaccine (n = 5), and (5) subunit vaccine (n = 5). Rabbits were vaccinated two times, at weeks 0 and 1, with nanogel and subunit vaccines, respectively, and challenged with rabbit HEV at week 4. By week 11, rabbits vaccinated with the nanogel vaccine produced higher antibodies than those vaccinated with the subunit vaccine. Fecal viral shedding and viremia were identified in rabbits of the positive and nanogel control groups at weeks 6-10. However, there was no viral shedding and viremia in rabbits immunized with both the nanogel and subunit vaccines. Alanine aminotransferase and aspartate aminotransferase levels were not elevated in any rabbit. However, histopathological examination revealed much less hepatic inflammation in rabbits of the nanogel vaccine group compared to the positive and nanogel control groups. Significant increases in IL-12 and IFN-γlevels were identified from rabbits immunized with the nanogel vaccine. Collectively, these results indicate that the newly developed nanogel vaccine induced sufficient immunity leading to complete protection from HEV infection in rabbits. Application of this vaccine should be considered as a preventive measure against HEV infection in other animal species and humans.

Immune dissociation during acute hepatitis E infection

OBJECTIVE

We report the immune response during a case of acute HEV response in a patient with an acute hepatitis E virus (HEV) genotype 3 infection in the Netherlands.

METHODS

Cytokine evaluation was performed via multiplex cytokine array for 65 immune markers in plasma during the different phases of hepatitis.

RESULTS

The patient initially presented with features typical of acute viral hepatitis, with detectable HEV RNA in blood. This evolved into a cholestatic disease following peripheral clearance of the virus, leading to the demise of the patient. Real time PCR revealed the presence of HEV in liver tissue, suggestive of active intrahepatic infection despite clearance in blood. During the phase of detectable HEV RNA in serum, there was a surge in T-cell-related immune mediators, as well as interferon alpha and interferon gamma-induced protein 10 (IP-10), characteristic of a viral infection. After clearance of the virus in the blood and development of cholestatic hepatitis, several inflammatory markers subsided, followed by an increase in immune factors related to anti-inflammatory activity, as well as monocyte/macrophage-related markers, likely due to the intrahepatic presence of the virus.

CONCLUSIONS

This report describes the dissociation of intra- and extra-hepatic immune responses during acute HEV infection. As shedding of the virus became solely intrahepatic, an immune profile reflective of the activity of hepatic resident cells was observed.

Hepatitis E and Allogeneic Hematopoietic Stem Cell Transplantation: A French Nationwide SFGM-TC Retrospective Study

Usually self-limited, hepatitis E virus (HEV) infection may evolve to chronicity and cirrhosis in immunosuppressed patients. HEV infection has been described in solid-organ transplantation and hematology patients, but for allogeneic hematopoietic stem cell transplant (alloHSCT) recipients, only small cohorts are available. This retrospective nationwide multi-center series aimed to describe HEV diagnostic practices in alloHSCT French centers, and the course of infection in the context of alloHSCT. Twenty-nine out of 37 centers participated. HEV search in case of liver function tests (LFT) abnormalities was never performed in 24% of centers, occasionally in 55%, and systematically in 21%. Twenty-five cases of active HEV infection were diagnosed in seven centers, all because of LFT abnormalities, by blood nucleic acid testing. HEV infection was diagnosed in three patients before alloHSCT; HEV infection did not influence transplantation planning, and resolved spontaneously before or after alloHSCT. Twenty-two patients were diagnosed a median of 283 days after alloHSCT. Nine patients (41%) had spontaneous viral clearance, mostly after immunosuppressive treatment decrease. Thirteen patients (59%) received ribavirin, with sustained viral clearance in 11/12 evaluable patients. We observed three HEV recurrences but no HEV-related death or liver failure, nor evolution to cirrhosis.

Cross-sectional Seroprevalence and Genotype of Hepatitis E Virus in Humans and Swine in a High-density Pig-farming Area in Central China

Hepatitis E virus (HEV) infection is a common public health problem in developing countries. However, the current prevalence of HEV and the relationship of HEV genotype between swine and human within high-density pig-farming areas in central China are still inadequately understood. Here, cross-sectional serological and genotypic surveys of HEV among the 1232 general population, 273 workers occupationally exposed to swine, and 276 pigs in a high-density pig-breeding area, were undertaken by ELISA and nested RT-PCR methods. Anti-HEV IgG was detected in 26.22% of general population and 48.35% of occupational workers. The prevalence of swine serum HEV-Ag was 6.52%. The prevalence of anti-HEV IgG was significantly higher among the workers occupationally exposed to swine than among the general population. An increased HEV seropositivity risk among the general population was associated with either being a peasant or male and was very strongly associated with the increase of age. Among the occupationally exposed group, the prevalence of anti-HEV IgG antibodies increased with age and working years. Among the 30 HEV-IgM-positive people, the infection rates of clerks in the public, peasants, pork retailers, and pig farmers were higher than those of others. A phylogenetic analysis revealed that all the isolates belonged to subgenotype 4_d, and four people and four pigs shared 97.04%-100% sequence homology. This study revealed a high HEV seroprevalence among the general population and workers occupationally exposed to swine in the Anlu City, and supports the notion that swine are a source of human HEV infection.

Prevalence of hepatitis E virus and reassessment of HIV and other hepatitis virus seroprevalences among French prison inmates

Background

Prison inmates are considered a high-risk population for blood-borne and enterically transmitted infections before and during their imprisonment. Hepatitis E virus (HEV) prevalence is unknown among French inmates, whereas a reassessment of human immunodeficiency virus (HIV), hepatitis A virus (HAV), hepatitis B virus (HBV) and hepatitis C virus (HCV) prevalences is required to describe the epidemiologic evolution in this high-risk population.

Methods

A prospective survey was conducted from June to December 2017 in Fresnes prison, a penitentiary center with 2,581 inmates. In addition to HIV, HAV, HBV and HCV testing, which is offered to all patients at admission, we systematically offered HEV screening. Retrospective serological data for HIV, HBV and HCV, collected annually from 2014 to 2017, were also used to assess evolution.

Results

In 2017, 1,093 inmates were screened for HEV, HIV, HAV, HBV and HCV. Prevalences in this population were 8.2%, 1.3%, 62.7%, 1.9% and 2.9%, respectively. HEV seroprevalence increased with age (p<0.0001) and was higher among Eastern Europe born inmates (p<0.0001). Between 2014 and 2017, HIV seroprevalence remained steady, while a decrease in HBV and HCV seroprevalence was observed.

Conclusions

Compared to the reported prevalence in French blood donors, HEV seroprevalence was remarkably low in French inmates. HIV, HAV, HBV and HCV prevalences among prisoners were higher than reported in the general population.

Evidences of HEV genotype 3 persistence and reactivity in liver parenchyma from experimentally infected cynomolgus monkeys (Macaca fascicularis)

Hepatitis E virus genotype 3 (HEV-3) is an emerging zoonotic pathogen, responsible for sporadic cases of acute hepatitis E worldwide. Primate models have proven to be an essential tool for the study of HEV pathogenesis. Here we describe the outcomes of HEV infection in Macaca fascicularis (cynomolgus) inoculated experimentally with genotype 3. Eight adult cynomolgus macaques were inoculated intravenously with HEV-3 viral particles isolated from swine and human samples. Liver, spleen, duodenum, gallbladder and bile were sequential assessed up to the end-point of this study, 67 days post-inoculation (dpi). Our previously published findings showed that biochemical parameters return gradually to baseline levels at 55 dpi, whereas anti-HEV IgM and HEV RNA become undetectable in the serum and feces of all animals, indicating a non-viremic phase of recovery. Nevertheless, at a later stage during convalescence (67 dpi), the presence of HEV-3 RNA and antigen persist in central organs, even after peripheral viral clearance. Our results show that two cynomolgus inoculated with swine HEV-3 (animals I3 and O1) presented persistence of HEV RNA low titers in liver, gallbladder and bile. At this same stage of infection, HEV antigen (HEV Ag) could be detected in all infected animals, predominantly in non-reactive Kupffer cells (CD68+iNOS-) and sinusoidal lining cells. Simultaneously, CD4+, CD3+CD4+, and CD3+CD8+ immune cells were identified in hepatic sinusoids and small inflammatory clusters of lobular mononuclear cells, at the end-point of this study. Inability of HEV clearance in humans can result in chronic hepatitis, liver cirrhosis, with subsequent liver failure requiring transplantation. The results of our study support the persistence of HEV-3 during convalescence at 67 dpi, with active immune response in NHP. We alert to the inherent risk of viral transmission through liver transplantation, even in the absence of clinical and biochemical signs of acute infection. Thus, besides checking conventional serological markers of HEV infection, we strongly recommend HEV-3 RNA and antigen detection in liver explants as public health measure to prevent donor-recipient transmission and spread of hepatitis E.

Serological evidence of hepatitis E virus and influenza A virus infection in farmed wild boars in China

Hepatitis E virus (HEV) and influenza A virus (IAV) are two important pathogens which can infect humans and various animals causing public health problems. In this study, the seroprevalence and risk factors associated with HEV and IAV infection in farmed wild boars were investigated in China. A total of 758 serum samples were collected from farmed wild boars between 2015 and 2016, and antibodies against HEV and IAV were examined by enzyme-linked immunosorbent assay (ELISA) using commercially available kits. The overall prevalence of anti-HEV antibodies was 24.54% (186/758, 95% CI 21.48-27.60) in farmed wild boars. There were statistically significant differences in the HEV seroprevalence in farmed wild boars of different ages (<22 days: 8.33%; 22-66 days: 18.89%; >66 days: 26.36%) (P < 0.05) and different genders (50.00% in male and 23.49% in female) (P <  0.01). However, there was no statistically significant difference in the HEV seroprevalence in farmed wild boars of different regions and different years. The overall IAV seroprevalence was 5.80% (44/758, 95% CI 4.14-7.46), and there was no statistically significant difference in the IAV seroprevalence in farmed wild boars of different ages and genders, collected from different regions and different years. Our results indicate that HEV and IAV infections in farmed wild boars may pose a potential risk for human infection. To our knowledge, this is the first report of HEV and IAV seroprevalence in farmed wild boars in China, which provides baseline data for further studies and for control of HEV and IAV infection in farmed wild boars.

An Optimized High-Throughput Neutralization Assay for Hepatitis E Virus (HEV) Involving Detection of Secreted Porf2

Hepatitis E virus (HEV) is a common cause of acute hepatitis worldwide. Current methods for evaluating the neutralizing activity of HEV-specific antibodies include immunofluorescence focus assays (IFAs) and real-time PCR, which are insensitive and operationally complicated. Here, we developed a high-throughput neutralization assay by measuring secreted pORF2 levels using an HEV antigen enzyme-linked immunosorbent assay (ELISA) kit based on the highly replicating HEV genotype (gt) 3 strain Kernow. We evaluated the neutralizing activity of HEV-specific antibodies and the sera of vaccinated individuals (n = 15) by traditional IFA and the novel assay simultaneously. A linear regression analysis shows that there is a high degree of correlation between the two assays. Furthermore, the anti-HEV IgG levels exhibited moderate correlation with the neutralizing titers of the sera of vaccinated individuals, indicating that immunization with gt 1 can protect against gt 3 Kernow infection. We then determined specificity of the novel assay and the potential threshold of neutralizing capacity using anti-HEV IgG positive sera (n = 27) and anti-HEV IgG negative sera (n = 23). The neutralizing capacity of anti-HEV IgG positive sera was significantly stronger than that of anti-HEV IgG negative. In addition, ROC curve analysis shows that the potential threshold of neutralizing capacity of sera was 8.07, and the sensitivity and specificity of the novel assay was 88.6% and 100%, respectively. Our results suggest that the neutralization assay using the antigen ELISA kit could be a useful tool for HEV clinical research.

Hepatitis E seroprevalence and associated risk factors in Croatian liver transplant recipients

INTRODUCTION

Solid-organ transplant recipients are at risk of hepatitis E virus (HEV) infection. We analyzed the seroprevalence/risk factors of HEV in Croatian liver transplant recipients.

METHODS

Two hundred forty-two serum samples were tested for HEV immunoglobuline IgG/IgM and HEV RNA. Sociodemographic data and risk factors were collected using a questionnaire.

RESULTS

HEV IgG seroprevalence rate was 24.4%. Positive/equivocal HEV IgM were found in two patients. HEV RNA was not detected. Logistic regression showed that older age, female gender, rural area/farm, water well, and septic tank were associated with HEV seropositivity.

CONCLUSIONS

This study revealed a high exposure rate to HEV in Croatian liver recipients.

Different Outcomes of Experimental Hepatitis E Virus Infection in Diverse Mouse Strains, Wistar Rats, and Rabbits

Hepatitis E virus (HEV) is the causative agent of acute hepatitis E in humans in developing countries, but autochthonous cases of zoonotic genotype 3 (HEV-3) infection also occur in industrialized countries. In contrast to swine, rats, and rabbits, natural HEV infections in mice have not yet been demonstrated. The pig represents a well-established large animal model for HEV-3 infection, but a suitable small animal model mimicking natural HEV-3 infection is currently missing. Therefore, we experimentally inoculated C57BL/6 mice (wild-type, IFNAR^−/−, CD4^−/−, CD8^−/−) and BALB/c nude (nu/nu) mice, Wistar rats, and European rabbits with a wild boar-derived HEV-3 strain and monitored virus replication and shedding, as well as humoral immune responses. HEV RNA and anti-HEV antibodies were detected in one and two out of eight of the rats and all rabbits inoculated, respectively, but not in any of the mouse strains tested. Remarkably, immunosuppressive dexamethasone treatment of rats did not enhance their susceptibility to HEV infection. In rabbits, immunization with recombinant HEV-3 and ratHEV capsid proteins induced protection against HEV-3 challenge. In conclusion, the rabbit model for HEV-3 infection may serve as a suitable alternative to the non-human primate and swine models, and as an appropriate basis for vaccine evaluation studies.

Effects of hepatitis E virus infection on interferon production via ISG15

AIM

To assess the effects of hepatitis E virus (HEV) on the production of type I interferons (IFNs) and determine the underlying mechanisms.

METHODS

We measured the production of interferon (IFN)-alpha and -beta (-α/β) in genotype 3 HEV-infected C3A cells at different time points (0, 8, 12, 24, 48, 72 and 120 h) by enzyme-linked immunosorbent assay (ELISA). The expression levels of IFN-stimulated gene (ISG)15 in HEV-infected C3A cells at different time points were tested by western blotting. The plasmid-expressing open reading frame 3 (ORF3) or control plasmids (green fluorescent protein-expressing) were transfected into C3A cells, and the levels of IFN-α/β and ISG15 were evaluated, respectively. Furthermore, the plasmid-expressing ISG15 or small interfering RNA-inhibiting ISG15 was transfected into infected C3A cells. Then, the production of IFN-α/β was also measured by ELISA.

RESULTS

We showed that genotype 3 HEV could enhance the production of IFN-α/β and induce elevation of ISG15 in C3A cells. HEV ORF3 protein could enhance the production of IFN-α/β and the expression of ISG15. Additionally, ISG15 silencing enhanced the production of IFN-α/β. Overexpression of ISG15 resulted in the reduction of IFN-α/β.

CONCLUSION

HEV may promote production of IFN-α/β and expression of ISG15 via ORF3 in the early stages, and increased ISG15 subsequently inhibited the production of IFN-α/β.

Seroprevalence of Hepatitis E Virus in Roma Settlements: A Comparison with the General Population in Slovakia

Hepatitis E infection is one of the most frequent causes of acute hepatitis in the world. Currently five human genotypes with different geographical distributions and distinct epidemiologic patterns are identified. In Slovakia, only rare cases of hepatitis E have been reported in past years. Because the most important risk factors associated with HEV infection include consumption of contaminated pork meat and poor hygienic standards, the aim of the study was to evaluate the prevalence of anti-HEV total antibodies and the main risk factors for HEV in the population living in separated and segregated Roma settlements (n = 195), which represent places with increased risk of infection in Slovakia and to compare it with the prevalence in the general population (n = 69). Of 264 respondents included in the study, 47 (17.8%) showed positivity for anti-HEV antibodies, 42 of whom were Roma (21.5%, n = 195) and 5 (7.2%, n = 69) non-Roma. The population living in Roma settlements lives in poorer conditions and are at higher risk of HEV in comparison to the general population. However, differences in living conditions within the settlements do not contributed to lower risk of HEV antibody prevalence between Roma living in settlements.

Prevalence of hepatitis E virus antibodies and infection in New Zealand blood donors

AIM

Blood transfusion is one route of transmission of hepatitis E virus (HEV). The aim of this study was to assess both the prevalence of HEV antibodies and HEV infection in New Zealand blood donors.

METHOD

To determine HEV seroprevalence, donor plasma samples (n=1,013) were tested for HEV antibodies using two commercially available ELISA kits, the Wantai HEV IgG ELISA and the MP Diagnostics HEV ELISA 4.0. To assess the prevalence of HEV infection, pooled plasma samples from individual plasma donors (n=5,000) were tested for HEV RNA using RT-qPCR. Samples that tested HEV antibody positive or gave an equivocal result with either ELISA were also tested for HEV RNA.

RESULTS

The HEV seroprevalence in New Zealand blood donors was 9.7% using the Wantai HEV IgG ELISA and 8.1% using the MP Diagnostics HEV ELISA 4.0. The presence of HEV antibodies was significantly and positively correlated with increasing donor age. HEV RNA was not detected in any of the samples tested, indicating no evidence of current infection.

CONCLUSION

This study, the largest to date to assess HEV seroprevalence in New Zealand, provides valuable baseline information on HEV seroprevalence and infection in New Zealand blood donors. The seroprevalence rate in New Zealand is similar to that reported in other developed countries.

Hepatitis E: Update on Prevention and Control

Hepatitis E virus (HEV) is a common etiology of acute viral hepatitis worldwide. Recombinant HEV vaccines have been developed, but only one is commercially available and licensed in China since 2011. Epidemiological studies have identified genotype 3 as the major cause of chronic infection in immunocompromised individuals. Ribavirin has been shown to be effective as a monotherapy to induce HEV clearance in chronic patients who have undergone solid organ transplant (SOT) under immunosuppressive therapy. Efforts and improvements in prevention and control have been made to reduce the instances of acute and chronic hepatitis E in endemic and nonendemic countries. However, this review shows that further studies are required to demonstrate the importance of preventive vaccination and treatment worldwide, with emphasis on hepatitis E infection in the public health system.

Chronic hepatitis E virus infection in a cirrhotic patient: A case report

RATIONALE

Acute hepatitis E virus (HEV) infections are usually self-limiting in immunocompetent patients. HEV persistence has been described only in immunosuppressed patients such as solid-organ transplant recipients, patients with hematological diseases, or patients with human immunodeficiency virus (HIV) infection.

PATIENT CONCERNS

A 61-year-old patient was admitted in hospital for jaundice and asthenia.

DIAGNOSES

The patient had underlying cirrhosis and developed a chronic HEV infection.

INTERVENTION

Ribavirin therapy was initiated.

OUTCOMES

Ribavirin therapy for 12 months allowed the clearance of the virus and HEV viral load remained undetectable thereafter. This patient had taken no immunosuppressive drugs, was not suffering from any autoimmune disease and was not infected with HIV. We studied the patient's anti-HEV immune response months after the viral clearance. His peripheral blood mononuclear cells (PBMC) were stimulated in vitro by HEV peptides. The patient had a mild T lymphopenia, but polyclonal stimulation of PBMC showed a robust T cell response. The response of his anti-HEV specific interferon-γ producing T cells was low.

LESSONS

Other studies are now needed to identify the population with a chronic evolution of HEV infection despite no apparent immunodepression.

Risk Analysis and Occurrence of Hepatitis E Virus (HEV) in Domestic Swine in Northeast Brazil

Anti-HEV antibodies were detected in animals from abattoir and in farms from northeast Brazil. Our results suggest that HEV is highly disseminated in the swine population and might present a great risk to animal handlers and for consumption of raw or undercooked meat and meat products in northeast Brazil.

[A sero-epidemiological study of hepatitis E among general population in Shandong Province of China in 2014]

Objective: To analyze the sero-epidemiological characteristics of hepatitis E virus (HEV) in Shandong province, and thereby to provide evidence for the policy-making of hepatitis E prevention and control. Methods: The inhabitants aged between 1-59 years old were randomly selected to participate in the study by two-stage stratified random sampling method from 12 counties in Shandong province in October, 2014. Firstly two townships were selected from each county by probability proportional to size sampling (PPS) method. A total of 5 229 participants aged 1-59 years old were selected by stratified random sampling method. All the participants finished a questionnaire survey and a venous blood sample (3-5 ml) was collected from each to test anti-HEV IgG by enzyme-linked assay (ELISA). The weighted prevalence of anti-HEV IgG with different demographic characteristics was estimated. The variance of the positive rate of anti-HEV IgG was calculated by Taylor series linearization method, as well as its 95%CI. A statistical test was conducted to compare the rate of its 95%CI, and the results in the present study were compared with those in sero-survey in 2006. Results: A total of 5 229 subjects entered the final analysis in 2014. The overall weighed prevalence of anti-HEV IgG was 9.19% (95%CI: 6.18%-12.20%) among natural population in Shandong province, decreased by 19.88% in comparison with that in 2006 sero-survey (11.47%, 95%CI: 8.92%-14.02%). The prevalence increased with age increasing (χ(2trend)=288.11, P<0.001) in 2014, which was similar to the result in 2006 sero-survey. Except for 1-4 years old group, the prevalence of anti-HEV IgG in the other age groups were lower than it in the corresponding groups in 2006. The prevalence of anti-HEV IgG in urban (8.19%, 95%CI: 0.00-22.23%), rural areas (9.69%, 95%CI: 4.99%-14.38%), eastern areas (12.70%, 95%CI: 0.00-27.72%), central areas (4.74%, 95%CI: 0.00-9.91%) and western areas (9.32%, 95%CI: 0.69%-17.94%) in 2014 were all lower than the corresponding prevalences (11.39%, 95%CI: 8.17%-14.62%; 11.92%, 95%CI: 8.75%-15.08%; 22.77%, 95%CI: 14.99%-30.55%; 7.97%, 95%CI: 4.75%-11.20%; 10.59%, 95%CI: 6.37%-14.82%) in 2006 survey. The prevalence of anti-HEV IgG in coastal areas (16.56%, 95%CI: 12.94%-20.18%) and inland areas (7.63%, 95%CI: 5.16%-10.10%) in 2014 were lower than it in the corresponding areas (28.04%, 95%CI: 20.45%-35.64%; 9.50%, 95%CI: 7.31%-11.70%) in 2006 survey. The prevalence among peasant (11.98%, 95%CI: 8.20%-15.76%), worker (9.68%, 95%CI: 4.48%-14.88%), cadre (13.90%, 95%CI: 7.47%-20.33%), service provider (12.26%, 95%CI: 1.80%-22.73%) in 2014 survey were lower than it among the corresponding populations (13.76%, 95%CI: 10.15%-17.38%; 21.11%, 95%CI: 12.67%-29.55%; 17.81%, 95%CI: 7.63%-28.00%; 21.08%, 95%CI: 0.03%-42.12%) in 2006 survey. Conclusion: The prevalence of anti-HEV IgG has decreased in Shandong province in the recent years, but the epidemiological characteristics found no obvious changes. HEV susceptibility in natural population was generally high. Hepatitis E vaccines were recommended to be used in HEV high-risk population in the province.

RIG-I is a key antiviral interferon-stimulated gene against hepatitis E virus regardless of interferon production

Interferons (IFNs) are broad antiviral cytokines that exert their function by inducing the transcription of hundreds of IFN-stimulated genes (ISGs). However, little is known about the antiviral potential of these cellular effectors on hepatitis E virus (HEV) infection, the leading cause of acute hepatitis globally. In this study, we profiled the antiviral potential of a panel of important human ISGs on HEV replication in cell culture models by overexpression of an individual ISG. The mechanism of action of the key anti-HEV ISG was further studied. We identified retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated protein 5, and IFN regulatory factor 1 (IRF1) as the key anti-HEV ISGs. We found that basal expression of RIG-I restricts HEV infection. Pharmacological activation of the RIG-I pathway by its natural ligand 5'-triphosphate RNA potently inhibits HEV replication. Overexpression of RIG-I activates the transcription of a wide range of ISGs. RIG-I also mediates but does not overlap with IFN-α-initiated ISG transcription. Although it is classically recognized that RIG-I exerts antiviral activity through the induction of IFN production by IRF3 and IRF7, we reveal an IFN-independent antiviral mechanism of RIG-I in combating HEV infection. We found that activation of RIG-I stimulates an antiviral response independent of IRF3 and IRF7 and regardless of IFN production. However, it is partially through activation of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade of IFN signaling. RIG-I activated two distinct categories of ISGs, one JAK-STAT-dependent and the other JAK-STAT-independent, which coordinately contribute to the anti-HEV activity.

CONCLUSION

We identified RIG-I as an important anti-HEV ISG that can be pharmacologically activated; activation of RIG-I stimulates the cellular innate immunity against HEV regardless of IFN production but partially through the JAK-STAT cascade of IFN signaling. (Hepatology 2017;65:1823-1839).

Hepatitis E virus persists in the presence of a type III interferon response

The RIG-I-like RNA helicase (RLR)-mediated interferon (IFN) response plays a pivotal role in the hepatic antiviral immunity. The hepatitis A virus (HAV) and the hepatitis C virus (HCV) counter this response by encoding a viral protease that cleaves the mitochondria antiviral signaling protein (MAVS), a common signaling adaptor for RLRs. However, a third hepatotropic RNA virus, the hepatitis E virus (HEV), does not appear to encode a functional protease yet persists in infected cells. We investigated HEV-induced IFN responses in human hepatoma cells and primary human hepatocytes. HEV infection resulted in persistent virus replication despite poor spread. This was companied by a type III IFN response that upregulated multiple IFN-stimulated genes (ISGs), but type I IFNs were barely detected. Blocking type III IFN production or signaling resulted in reduced ISG expression and enhanced HEV replication. Unlike HAV and HCV, HEV did not cleave MAVS; MAVS protein size, mitochondrial localization, and function remained unaltered in HEV-replicating cells. Depletion of MAVS or MDA5, and to a less extent RIG-I, also diminished IFN production and increased HEV replication. Furthermore, persistent activation of the JAK/STAT signaling rendered infected cells refractory to exogenous IFN treatment, and depletion of MAVS or the receptor for type III IFNs restored the IFN responsiveness. Collectively, these results indicate that unlike other hepatotropic RNA viruses, HEV does not target MAVS and its persistence is associated with continuous production of type III IFNs.

Comparison of foeto-maternal outcome in pregnant women with hepatitis E - A review of 12 years

OBJECTIVE

To compare adverse maternal and foetal outcome in pregnant women with hepatitis E immunoglobulin M reactive versus non-reactive.

METHODS

This retrospective study was conducted at the Aga Khan University Hospital, Karachi, and comprised records of pregnant patients at any gestational age with clinical and biochemical evidence of hepatitis E from January 2002 and December 2014. . Maternal and perinatal outcome of the subjects were analysed. SPSS 20 was used for data analysis.

RESULTS

Out of the 200 subjects, 168(84 %) were hepatitis E immunoglobulin M reactive and 32(16%) were non-reactive. The overall mean age was 26.7±4.5 years. Also, 12(7%) patients in the immunoglobulin M reactive group were admitted to intensive care unit compared to no one from the non-reactive group. Similarly fulminant hepatic failure was seen in 12(7.1%) patients in the immunoglobulin M reactive group compared to no one in the other group. Post-partum haemorrhage was more frequent in the immunoglobulin M reactive group compared to the non-reactive group. There were 5(3%) maternal deaths in the reactive group compared to no death in the other group. Moreover, 34(20.2%) neonates of the immunoglobulin M reactive group needed neonatal intensive care unit admission compared to none in the non-reactive group. There were 4(2.4%) neonatal deaths in the reactive group.

CONCLUSIONS

Participants in the immunoglobulin M reactive group had a higher percentage of adverse foeto-maternal outcomes compared to the non-reactive group.

Genetic and physicochemical analyses of a novel ferret hepatitis E virus, and clinical signs of infection after birth

A novel cluster of five ferret hepatitis E virus (HEV) strains was detected from nine laboratory ferrets (Mustela putorius furo) imported from a ferret farm in the U.S. Our detection of ferret HEV RNA and anti-HEV antibodies, and alanine aminotransferase (ALT) value assessment indicated that all of the 9 ferrets were infected with ferret HEV, and that the infection exhibited three patterns: sub-clinical infection (n=2), acute hepatitis (n=6) and persistent infection (n=1). Next-generation sequence analyses of the entire genome sequences of the five strains revealed that their nucleotide sequence identities ranged from 99.5% to 99.9%, indicating that genetically similar ferret HEVs had been circulating at this the U.S. ferret farm. In contrast, the strains shared 82% and 89% nucleotide sequence identities with other ferret HEV that isolated from the Netherlands (JN998607) and the U.S. (AB890374), suggesting that these strains form a novel cluster of ferret HEV with diverse genomes depending on the region where their host. Particles with a diameter of ~35nm at a density of 1.201g/cm³ were observed in the fecal specimens by electron microscopy. There was no evidence that the particles were associated with the cell membrane. The ferret HEV RNA was not constantly detected in urine, suggesting that the excretion of ferret HEV into urine is not a common feature of HEV infection.

Cynomolgus monkeys are successfully and persistently infected with hepatitis E virus genotype 3 (HEV-3) after long-term immunosuppressive therapy

Epidemiological studies found that hepatitis E virus genotype 3 (HEV-3) infection was associated with chronic hepatitis and cirrhosis in immunocompromised patients. Our study aimed to investigate the relationship between the host immunosuppressive status and the occurrence of HEV-related chronic hepatitis. Here we describe a successful experimental study, using cynomolgus monkeys previously treated with tacrolimus, a potent calcineurin inhibitor immunosuppressant, and infected with a Brazilian HEV-3 strain isolated from naturally infected pigs. HEV infected monkeys were followed up during 160 days post infection (dpi) by clinical signs; virological, biochemical and haematological parameters; and liver histopathology. The tacrolimus blood levels were monitored throughout the experiment. Immunosuppression was confirmed by clinical and laboratorial findings, such as: moderate weight loss, alopecia, and herpes virus opportunistic infection. In this study, chronic HEV infection was characterized by the mild increase of liver enzymes serum levels; persistent RNA viremia and viral faecal shedding; and liver histopathology. Three out of four immunosuppressed monkeys showed recurrent HEV RNA detection in liver samples, evident hepatocellular ballooning degeneration, mild to severe macro and microvesicular steatosis (zone 1), scattered hepatocellular apoptosis, and lobular focal inflammation. At 69 dpi, liver biopsies of all infected monkeys revealed evident ballooning degeneration (zone 3), discrete hepatocellular apoptosis, and at most mild portal and intra-acinar focal inflammation. At 160 dpi, the three chronically HEV infected monkeys showed microscopic features (piecemeal necrosis) corresponding to chronic hepatitis in absence of fibrosis and cirrhosis in liver parenchyma. Within 4-months follow up, the tacrolimus-immunosuppressed cynomolgus monkeys infected with a Brazilian swine HEV-3 strain exhibited more severe hepatic lesions progressing to chronic hepatitis without liver fibrosis, similarly as shown in tacrolimus-immunosuppressed solid organ transplant (SOT) recipients. The cause-effect relationship between HEV infection and tacrolimus treatment was confirmed in this experiment.

HEV infection in French HIV-infected patients

OBJECTIVES

The reported prevalence of anti-hepatitis E virus antibodies in HIV-positive patients from industrialized countries varies greatly. It is also difficult to compare these data with the anti-IgG prevalence in the general population because age and sex are not matched in most studies. Moreover, MSM are at increased risk of viral hepatitis.

METHODS

HEV is endemic in southwestern France. We investigated therefore 300 HIV-infected patients consecutively attending the out-patient clinic of Toulouse University Hospital. Each HIV-infected patient was matched for sex and age with 2 healthy blood donors from the same area. They were tested for anti-HEV IgM and IgG.

RESULTS

Anti-HEV IgG was found in 116 HIV-infected patients (38.7%) and in 284 matched controls (47.3%, p = 0.027). However, anti-HEV IgG concentration tended to be lower in HIV-patients than in controls. Anti-HEV IgM prevalence was similar HIV-infected patients (3.6%) and in matched controls (3.8%, p = 0.85).

CONCLUSION

The prevalence and concentrations of anti-HEV IgG in HIV-infected patients from Southern-France were lower than in controls, suggesting a weaker humoral response. But their prevalences of anti-HEV IgM were similar, indicating a high incidence of HEV infection. These data do not indicate that HEV is transmitted sexually.

A Nationwide Survey of Hepatitis E Virus Infection and Chronic Hepatitis E in Liver Transplant Recipients in Japan

Background

Recently, chronic hepatitis E has been increasingly reported in organ transplant recipients in European countries. In Japan, the prevalence of hepatitis E virus (HEV) infection after transplantation remains unclear, so we conducted a nationwide cross-sectional study to clarify the prevalence of chronic HEV infection in Japanese liver transplant recipients.

Methods

A total of 1893 liver transplant recipients in 17 university hospitals in Japan were examined for the presence of immunoglobulin G (IgG), IgM and IgA classes of anti-HEV antibodies, and HEV RNA in serum.

Findings

The prevalence of anti-HEV IgG, IgM and IgA class antibodies was 2.9% (54/1893), 0.05% (1/1893) and 0% (0/1893), respectively. Of 1651 patients tested for HEV RNA, two patients (0.12%) were found to be positive and developed chronic infection after liver transplantation. In both cases, HEV RNA was also detected in one of the blood products transfused at the perioperative period. Analysis of the HEV genomes revealed that the HEV isolates obtained from the recipients and the transfused blood products were identical in both cases, indicating transfusion-transmitted HEV infection.

Interpretation

The prevalence of HEV antibodies in liver transplant recipients was 2.9%, which is low compared with the healthy population in Japan and with organ transplant recipients in European countries; however, the present study found, for the first time, two Japanese patients with chronic HEV infection that was acquired via blood transfusion during or after liver transplantation.

•

We conducted the multicenter survey for HEV infection in liver transplant recipients.

•

Though the chronic HEV infection is rare, transfusion-transmitted cases were detected.

•

Blood products can be a risk of chronic HEV infection in transplant recipients.

TGF-β1 and contact mediated suppression by CD4+CD25+CD127- T regulatory cells of patients with self-limiting hepatitis E

BACKGROUND AND AIM

Literature on the role of Regulatory T cells (Tregs) in acute viral infections is limited. Having established that the Tregs in self-limiting hepatitis E infection are elevated and functional, this study has focused on characterizing the specificity, phenotypes and identifying the molecules or factors responsible for enhancement of Treg cells and abrogation of Treg-mediated suppression in hepatitis E.

METHODS

HEV rORF2p specific (a) Treg frequency, subset analysis and expression of surface and intracellular markers on Tregs and CFSE based functional analysis by flow cytometry (b) key cytokines quantification by multiplex (c) suppressive functional assay in the presence of anti-TGF-β₁ or anti-IL-10 or both antibodies or Transwell insert or in combination were performed on samples from 58 acute patients (AVH-E), 45 recovered individuals from hepatitis E and 55 controls.

RESULTS

In AVH-E, the increased frequencies of Tregs and Teff cells were HEV rORF2p specific and Treg cells were of effector memory phenotype. Higher expressions of HEV rORF2p stimulated CTLA-4, GITR, PD1L, CD103, CD39, TLR2 and TGF-β₁ molecules on Tregs of AVH-E were observed. Tregs produced TGF-β₁ and inhibited the secretion of IFN-γ. Transwell insert and cytokines blocking assays indicated Tregs mediated suppression in AVH-E patients is majorly TGF-β₁ mediated and partly cell-cell contact mediated.

CONCLUSION

Overall, we have identified beneficial involvement of HEV specific, functional Tregs and TGF-β₁ as the regulatory molecule responsible for enhancement of Tregs in self-limiting HEV infection. Therefore, use of TGF-β₁ as a possible supplement for boosting Treg response in recovery from severe hepatitis E needs evaluation.

Hepatitis E Seroprevalence in Europe: A Meta-Analysis

There have been large numbers of studies on anti-HEV IgG seroprevalence in Europe, however, the results of these studies have produced high variability of seroprevalence rates, making interpretation increasingly problematic. Therefore, the aim of this study was to develop a clearer understanding of anti-HEV IgG seroprevalence in Europe and identify risk groups for HEV exposure by a meta-analysis of published studies.

METHODS

All European HEV-seroprevalence studies from 2003 to 2015 were reviewed. Data were stratified by assay, geographical location, and patient cohort (general population, patients with HIV, solid-organ transplant recipients, chronic liver disease patients, and individuals in contact with swine/wild animals). Data were pooled using a mixed-effects model.

RESULTS

Four hundred thirty-two studies were initially identified, of which 73 studies were included in the analysis. Seroprevalence estimates ranged from 0.6% to 52.5%, increased with age, but were unrelated to gender. General population seroprevalence varied depending on assays: Wantai (WT): 17%, Mikrogen (MG): 10%, MP-diagnostics (MP): 7%, DiaPro: 4%, Abbott 2%. The WT assay reported significantly higher seroprevalence rates across all cohorts (p < 0.001). Individuals in contact with swine/wild animals had significantly higher seroprevalence rates than the general population, irrespective of assay (p < 0.0001). There was no difference between any other cohorts. The highest seroprevalence was observed in France (WT: 32%, MP: 16%) the lowest in Italy (WT: 7.5%, MP 0.9%). Seroprevalence varied between and within countries. The observed heterogeneity was attributed to geographical region (23%), assay employed (23%) and study cohort (7%).

CONCLUSION

Seroprevalcence rates primarily depend on the seroassy that is used, followed by the geographical region and study cohort. Seroprevalence is higher in individuals exposed to swine and/or wild animals, and increases with age.