Hepatitis E virus-related cirrhosis in kidney- and kidney-pancreas-transplant recipients

Evaluation of an antigen assay for diagnosing acute and chronic hepatitis E genotype 4 infection

BACKGROUND AND AIM

Results obtained from different hepatitis E virus (HEV) tests are usually inconsistent. The detection of serum HEV antigen (Ag) has been suggested to be more sensitive for the diagnosis of genotypes 1 and 3 HEV.

METHODS

We compared the diagnostic accuracies of serum HEV Ag and HEV RNA by using 202 serum samples from patients suspected acute viral hepatitis.

RESULTS

The HEV Ag assay was 100% specific. The lower detected levels of viremia ranged from 10² to 10³  copies/mL. The sensitivity of the HEV Ag test was 90.5%. One of the 42 cases was negative for anti-HEV IgM, but HEV Ag was still detectable. The detectable period of HEV Ag was in concordance with the detectable period of HEV RNA. Serum HEV Ag was persistently detected in two cases of chronic hepatitis E, confirmed by the persistent presence of HEV RNA despite being negative for anti-HEV IgM. HEV Ag demonstrated good consistency with positive HEV RNA (k = 0.938, P < 0.001). Receiver operating characteristic analysis of HEV Ag suggested a second cut-off value of >0.095 to predict HEV patients with 95.24% sensitivity and 98.75% specificity, and the area under the curve was 0.9887, which was higher than that of three commercial anti-HEV IgM ELISA tests.

CONCLUSIONS

The presence of HEV Ag has good consistency with HEV RNA in both acute and chronic genotype 4 hepatitis E. HEV Ag is a more promising serum marker to identify active genotype 4 HEV infection than anti-HEV IgM and HEV RNA.

Hepatitis E: an underestimated emerging threat

Hepatitis E virus (HEV) is the most common cause of viral hepatitis in the world. It is estimated that millions of people are infected every year, resulting in tens of thousands of deaths. However, these estimates do not include industrialized regions and are based on studies which employ assays now known to have inferior sensitivity. As such, this is likely to represent a massive underestimate of the true global burden of disease. In the developing world, HEV causes large outbreaks and presents a significant public-health problem. Until recently HEV was thought to be uncommon in industrialized countries, and of little relevance to clinicians in these settings. We now know that this is incorrect, and that HEV is actually very common in developed regions. HEV has proved difficult to study in vitro, with reliable models only recently becoming available. Our understanding of the lifecycle of HEV is therefore incomplete. Routes of transmission vary by genotype and location: endemic regions experience large waterborne epidemics, while sporadic cases in industrialized regions are zoonotic infections likely spread via the food chain. Both acute and chronic infection has been observed, and a wide range of extrahepatic manifestations have been reported. This includes neurological, haematological and renal conditions. As the complete clinical phenotype of HEV infection is yet to be characterized, a large proportion of cases go unrecognized or misdiagnosed. In many cases HEV infection does not feature in the differential diagnosis due to a lack of knowledge and awareness of the disease amongst clinicians. In combination, these factors have contributed to an underestimation of the threat posed by HEV. Improvements are required in terms of recognition and diagnosis of HEV infection if we are to understand the natural history of the disease, improve management and reduce the burden of disease around the world.

Prevalence and characteristics of hepatitis E virus infection in kidney transplant recipients: A single-center experience in Japan

BACKGROUND

Hepatitis E virus (HEV) infection can lead to chronic hepatitis in solid organ transplant recipients. To investigate whether HEV infection influences outcomes following kidney transplantation, we examined the prevalence of HEV infection and clinical characteristics of kidney transplant recipients in our hospital.

METHODS

Our cross-sectional study included 184 kidney transplant recipients. Blood samples were obtained from all patients to detect anti-HEV immunoglobulin (Ig)A, IgM, and IgG by enzyme-linked immunosorbent assay and HEV RNA by reverse transcription polymerase chain reaction. Clinical data were collected from medical charts for all patients.

RESULTS

The prevalence of anti-HEV IgG was 8/184 (4.3%). Anti-HEV IgA, anti-HEV IgM, and HEV RNA were not detected in any patients. Compared to their anti-HEV IgG-negative counterparts, anti-HEV IgG-positive patients were significantly older at the time of transplantation, and they were more likely to receive kidneys from deceased donors. No significant differences in other characteristics such as the prevalence of primary cause of end-stage renal disease, blood transfusion, and immunosuppressive therapy use; liver and renal function; and the frequencies of hepatitis B and hepatitis C virus infection were observed according to the patients' anti-HEV IgG status.

CONCLUSION

HEV infection had no significant influence on the outcomes of kidney transplantation at our institution. However, HEV infection should be recognized in kidney transplant recipients similarly as hepatitis B and hepatitis C virus infection in cases of liver dysfunction.

Performance of a commercial assay for detecting and quantifying HEV RNA in faeces

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No commercial HEV RNA assay is validated for use in faecal samples.

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Monitoring HEV faecal excretion is recommended for managing chronic HEV infection in solid-organ transplant recipients.

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We evaluated the Altona assay by testing patients on ribavirin therapy.

Background

Detecting hepatitis E virus (HEV) RNA in faeces is useful for diagnosing and monitoring HEV infections, particularly in immunocompromised patients requiring ribavirin therapy.

Objectives

This study evaluated the performance of the Altona RealStar HEV RNA kit for detecting and quantifying HEV in faeces.

Study design

RNA was extracted from 94 stool samples by two methods: QIAamp Viral RNA Mini kit and MagNA Pure 96 automate. The Altona results were compared to a reference laboratory-developed accredited ISO15189 RT-PCR assay.

Results

The Altona and reference assays detect HEV RNA in 77/93 (82.8%) and 83/93 (89.2%) of the QIAamp extracted samples, respectively, after exclusion of invalid result; they detected HEV RNA in 67/92 (72.8%) and 66/92 (71.7%) of the MagNA Pure extracted samples, respectively, which emphasizes the importance of the RNA extraction method. The HEV RNA concentrations obtained with Altona RT-PCR and the reference RT-PCR were well correlated whatever the extraction method, and Bland Altman analyses indicated that the Altona values were higher than the reference assay values. The Altona values for QIAamp-extracted and MagNA Pure-extracted HEV RNA were very similar.

Conclusions

The Altona RealStar assay is suitable for quantifying HEV RNA in the faeces and monitoring HEV RNA shedding during ribavirin therapy. Extraction is critical for detecting faecal HEV with high performance RT-PCR assays.

Prevalence, morbidity, and therapy of hepatitis E virus infection in pediatric renal allograft recipients

BACKGROUND

Hepatitis E virus (HEV) infection in immunocompromised patients such as solid organ transplant recipients may bear a high risk of becoming a chronic infection with progression to liver cirrhosis. So far, data on HEV infection in pediatric renal transplant recipients are limited.

METHODS

This single-center cohort study investigated period prevalence, morbidity, and treatment of HEV infection in 90 pediatric renal allograft recipients aged 9.9 ± 5.6 years at transplantation (58.9% males). HEV serology was determined by enzyme-linked immunosorbent assay and immunoblot, HEV replication by quantitative nucleic acid testing.

RESULTS

Twelve of 90 (13.3%) patients were HEV seropositive, and 4/90 (4.4%) recipients showed active HEV replication (10³-10⁸ copies/mL, corresponding to 0.5 × 10³ and 0.5 × 10⁸ WHO IU/mL) in serum and stool. In all patients with HEV replication, genotype 3 was identified by partial sequencing of HEV ORF1 and ORF2 and phylogenetic analysis. All patients with HEV replication developed chronic infection associated with moderately elevated liver enzymes. HEV replication was unresponsive to reduction of immunosuppression, whereas ribavirin monotherapy (mean dosage 9.7 ± 3.6 mg/kg per day over 85 ± 11 days) was associated with sustained viral clearance and normalization of liver enzymes in all patients. Ribavirin therapy was associated with reversible, hyporegenerative anemia.

CONCLUSIONS

Given an HEV seroprevalence of 13.3% in pediatric renal transplant recipients and an HEV viremia of 4.4%, HEV infection should be considered in patients with otherwise unexplained elevation of liver enzymes. HEV infection does not necessarily respond to reduction of immunosuppressive therapy, but can be effectively and safely treated with ribavirin.

Development of new hepatitis E vaccines

Hepatitis E virus (HEV) infection is an emerging zoonotic disease posing a severe threat to public health in the world, especially to pregnant women. Currently, no specific treatments are available for HEV infection. Therefore, it is crucial to develop vaccine to prevent this infection. Although several potential candidate vaccines against HEV have been studied for their immunogenicity and efficacy, only Hecolin® which is developed by Xiamen Innovax Biotech Co., Ltd. and approved by China Food and Drug Administration (CFDA) in 2012, is the licensed HEV vaccine in the world so far. Extensive studies on safety, immunogenicity and efficacy in phase III clinical trials have shown that Hecolin® is a promising vaccine for HEV prevention and control. In this article, the advances on HEV vaccine development and research are briefly reviewed.

EASL Clinical Practice Guidelines on hepatitis E virus infection

Infection with hepatitis E virus (HEV) is a significant cause of morbidity and mortality, representing an important global health problem. Our understanding of HEV has changed completely over the past decade. Previously, HEV was thought to be limited to certain developing countries. We now know that HEV is endemic in most high-income countries and is largely a zoonotic infection. Given the paradigm shift in our understanding of zoonotic HEV and that locally acquired HEV is now the commonest cause of acute viral hepatitis in many European countries, the focus of these Clinical Practice Guidelines will be on HEV genotype 3 (and 4).

Dosing ribavirin in hepatitis E-infected solid organ transplant recipients

Hepatitis E virus (HEV) is the most common cause of viral hepatitis worldwide. Genotypes 1 and 2 (GT1 and GT2) are mainly present in developing countries, while GT3 and GT4 are prevalent in developed and high-income countries. In the majority of cases, HEV causes a self-limiting hepatitis. GT3 and GT4 can be responsible for a chronic hepatitis that can lead to cirrhosis in immunocompromized patients, i.e. solid-organ- and stem-cell-transplant-patients, human immunodeficiency virus-infected patients, and patients receiving chemotherapy or immunotherapy. HEV has also been associated with extra-hepatic manifestations such as neurologic disorders (Guillain-Barré Syndrome and neuralgic amyotrophy) and kidney disease. In patients with chronic hepatitis, reduction of immunosuppression, when possible, is the first therapeutic option. In the remaining patients, ribavirin therapy has been shown to very efficient for treating HEV infection leading to a sustained virological response in nearly 80-85% of patients. However, the mechanism of action of ribavirin in this setting is still unknown, as is the impact of HEV RNA polymerase mutations. There are unmet needs with regard to the treatment of chronic HEV with ribavirin. These include the optimal dosing and duration of treatment, and the potential beneficial effects of therapeutic drug monitoring on the virological response and the incidence of side effects. In the present review, we will provide an overview of HEV epidemiology, its mode of transmission and clinical manifestations, as well as its treatment by ribavirin with a focus on the drug's pharmacokinetics and dosing.

The Medicinal Chemistry of Antihepatitis Agents I

Since viral hepatitis, as discussed in preceding chapters, has emerged as a major public health problem throughout the world affecting several hundreds of millions of people, and since no effective chemotherapy has been developed so far that can completely treat viral hepatitis, attempts are continued to find potential drugs against this disease. In this respect, the development of medicinal chemistry has been rewarding, as it covers all aspects of drug design such as recognition of important drug targets, computational chemistry, optimization of drug activity based on their structure-activity relationship, finding the three-dimensional structures of compounds by X-ray crystallography, NMR, molecular dynamics, and then synthesis of the drugs and evaluating their activity. The present chapter, thus, presents such medicinal chemistry study on anti-HAV, anti-HDV, and anti-HEV drugs.

Hepatitis E: A Literature Review

Hepatitis E is the fifth known form of human viral hepatitis. Although not very common in our clinical practice, the incidence in Western countries is increasing. Infection with the hepatitis E virus (HEV) may be related to acute illness, liver failure, chronic hepatitis and cirrhosis. HEV itself is an RNA virus, with eight described genotypes (HEV 1-8), four of which more commonly affect humans and have, thus, been better studied. Besides liver manifestations, genotype 3 is also related to extra-hepatic manifestations, such as neurological, renal and rheumatological. Evolution to chronic disease occurs especially in patients who underwent transplantation, have hematological malignancies requiring chemotherapy, or have infection with the human immunodeficiency virus. The diagnosis may be difficult because of the low availability of tests and due to low sensibility and specificity. The acute form of illness does not have to be treated, but the chronic one does. We present here a literature review of hepatitis E and the relation between chronic hepatitis E and transplantation.

Hepatitis E virus infection

Hepatitis E virus (HEV) infection can lead to acute and chronic hepatitis as well as to extrahepatic manifestations such as neurological and renal disease; it is the most common cause of acute viral hepatitis worldwide. Four genotypes are responsible for most infection in humans, of which HEV genotypes 1 and 2 are obligate human pathogens and HEV genotypes 3 and 4 are mostly zoonotic. Until quite recently, HEV was considered to be mainly responsible for epidemics of acute hepatitis in developing regions owing to contamination of drinking water supplies with human faeces. However, HEV is increasingly being recognized as endemic in some developed regions. In this setting, infections occur through zoonotic transmission or contaminated blood products and can cause chronic hepatitis in immunocompromised individuals. HEV infections can be diagnosed by measuring anti-HEV antibodies, HEV RNA or viral capsid antigen in blood or stool. Although an effective HEV vaccine exists, it is only licensed for use in China. Acute hepatitis E is usually self-limiting and does not require specific treatment. Management of immunocompromised individuals involves lowering the dose of immunosuppressive drugs and/or treatment with the antiviral agent ribavirin.

Emerging Infections and Pertinent Infections Related to Travel for Patients with Primary Immunodeficiencies

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text.

Clinical and virological features of acute hepatitis E in Gunma prefecture, Japan between 2004 and 2015

AIM

To evaluate the clinical and virological features of acute hepatitis E (AH-E) in Gunma prefecture and focus on the hepatitis E virus (HEV) infection in immunocompromised patients.

METHODS

A total of 30 patients with AH-E diagnosed at our Gunma University Hospital, and located in 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan, and its affiliated hospitals from 2004 to 2015, were studied. We evaluated the detailed medical histories, laboratory examinations and virological features of these participants.

RESULTS

Of the 30 patients, 21 patients were men, with a median age of 61 years. Three of these patients had a history of recent oversea travel. A total of 14 patients had eaten raw or undercooked meat/viscera from animals, and two patients had contracted transfusion-transmitted AH-E. Eight patients were immunocompromised, including those with hematological disease, cancer receiving systemic chemotherapy and kidney transplant or connective tissue disease undergoing immunosuppressive medications. The alanine aminotransferase and total bilirubin levels were more significantly reduced in these immunocompromised patients than in the non-immunocompromised patients. Severe thrombocytopenia, an extra-hepatic manifestation of AH-E, occurred in one case. Among the 22 HEV strains whose subgenotype was determined, two were imported strains (1a and 1f), and 11 strains formed four distinct phylogenetic clusters within subgenotype 3b. The remaining nine strains differed from each other by 9.8-22.4%, and were classified into four subgenotypes (3a, 3b, 3e and 3f).

CONCLUSION

Markedly divergent HEV strains (3a, 3b, 3e and 3f) were found to circulate in Gunma. Although immunosuppression appears to play a crucial role in establishing chronic sequels, AH-E in eight immunocompromised patients, including transfusion-transmitted HEV infection in two patients, did not become chronic.

Hepatitis E virus: A potential threat for patients with liver disease and liver transplantation

Immunocompromised patients are at risk of acquiring acute hepatitis E virus infection (HEV), leading to chronicity. Chronic HEV infection is associated with persistent viraemia, raised transaminase activity, histological features associated with chronic hepatitis and evidence of rapid development of cirrhosis. Extrahepatic manifestations have been associated with HEV. Most frequently reported are neurological disorders with predominantly involvement of the peripheral nervous system. In patients using immunosuppressive drugs antibody production is often delayed and HEV RNA detection is superior to serology to detect infection. Therapeutic options for chronic HEV includes tapering immunosuppressive and secondly ribavirin, pegylated interferon alpha (PEG-IFN). Present recommendation is to treat chronic HEV patients for 3 months, asses serum HEV RNA and stool HEV RNA and stop therapy if both are undetectable. Studies are required to determine which other antiviral agents than ribavirin and (PEG-)IFN are of clinical utility in treating HEV in the minority of patients who do not respond to ribavirin.

Hepatitis E Virus (HEV) Detection and Quantification by a Real-Time Reverse Transcription-PCR Assay Calibrated to the World Health Organization Standard for HEV RNA

Hepatitis E virus (HEV) has emerged as a cause of chronic hepatitis among immunocompromised patients. Molecular assays have become important tools for the diagnosis and management of these chronically infected patients. A real-time reverse transcription-quantitative PCR (RT-qPCR) assay utilizing Pleiades probe chemistry and an RNA internal control for the simultaneous detection and quantification of HEV RNA in human serum was developed based on an adaptation of a previously described and broadly reactive primer set targeting the overlapping open reading frame 2/3 (ORF2/3) nucleotide sequence of HEV. A chimeric bovine viral diarrhea virus construct containing an HEV RNA insert (SynTura HEV) was developed, value assigned with the first World Health Organization (WHO) international standard for HEV RNA (code 6329/10), and used to prepare working assay calibrators and controls, which supported an assay quantification range of 100 to 5,000,000 IU/ml. The analytical sensitivity (95% detection rate) of this assay was 25.2 IU/ml (95% confidence interval [CI], 19.2 to 44.1 IU/ml). The assay successfully amplified 16 different HEV sequences with significant nucleotide mismatching in primer/probe binding regions, while evaluation of a WHO international reference panel for HEV genotypes (code 8578/13) showed viral load results falling within the result ranges generated by WHO collaborative study participants for all panel members (genotypes 1 to 4). Broadly reactive RT-qPCR primers targeting HEV ORF2/3 were successfully adapted for use in an assay based on Pleiades probe chemistry. The availability of secondary standards calibrated to the WHO HEV international standard can improve the standardization and performance of assays for the detection and quantification of HEV RNA.

Xenotransplantation - A special case of One Health

The chronic shortage of human transplants to treat tissue and organ failure has led to the development of xenotransplantation, the transplantation of cells, tissues and organs from another species to human recipients. For a number of reasons, pigs are best suited as donor animals. Successful, routine xenotransplantation would have an enormous impact on the health of the human population, including the young, who sometimes require a replacement organ or islet cells, but especially the elderly, who more often suffer the consequences of organ failure. The first form of xenotransplantation applied to humans is the use of pig islet cells to treat insulin-dependent diabetes, a procedure that will have a significant economic impact. However, although xenotransplantation using pig cells, tissues and organs may save and prolong the lives of patients, it may also be associated with the transmission of porcine microorganisms to the recipient, eventually resulting in emerging infectious diseases. For this reason, the health of both the donor animals and the human recipients represents a special and sensitive case of the One Health concept. Basic research leading to strategies how to prevent transmission of porcine microorganisms by selection of virus-free animals, treatment of donor pigs by antiviral drugs, vaccines, colostrum deprivation, early weaning, Caesarean delivery, embryo transfer and/or gene editing should be undertaken to supply an increasing number of potential recipients with urgently required transplants. The methods developed for the detection and elimination of porcine microorganisms in the context of xenotransplantation will also contribute to an improvement in the health of pig populations in general and an increase in the quality of meat products. At present, there is evidence for transmission of porcine viruses to humans eating pork and having contact with pigs, however the impact of these viruses on public health is still unknown.

Hepatitis E Pathogenesis

Although most hepatitis E virus (HEV) infections are asymptomatic, some can be severe, causing fulminant hepatitis and extra-hepatic manifestations, including neurological and kidney injuries. Chronic HEV infections may also occur in immunocompromised patients. This review describes how our understanding of the pathogenesis of HEV infection has progressed in recent years.

Detection of Hepatitis E Virus Genotype 1 Among Blood Donors From Southwest of Iran

BACKGROUND

Infection with hepatitis E virus (HEV) is endemic in developing countries and reveals significant regional differences. Several studies have reported virus transmission via blood transfusion. To date, however, no cases of HEV RNA detection in blood donors have been reported from Iran.

OBJECTIVES

The aim of this study was to determine the presence of HEV RNA in plasma samples of blood donors referred to a blood transfusion center in Shiraz in the southwest of Iran. The HEV genotypes were also investigated using nucleotide sequencing.

PATIENTS AND METHODS

Blood samples were collected from 700 blood donors who were referred to Fars blood transfusion organization from January to March 2014. Plasma samples were screened for the presence of HEV IgG and IgM antibodies by standard enzyme immunoassay. Samples seroreactive to anti-HEV were further tested for the presence of HEV RNA using nested polymerase chain reaction (PCR) with universal primers for detection of all four HEV genotypes. Positive PCR samples were then subjected to DNA sequencing for further analysis.

RESULTS

Fifty (50, 7.1%) out of 700 plasma samples tested positive for anti-HEV antibodies. HEV RNA was detected in 7/50 (12%) of the antibody-positive samples, the majority of which were IgM positive. Sequence analysis of seven isolates of the HEV RNA ORF 2 gene region revealed > 80% similarity with genotype 1.

CONCLUSIONS

The analysis indicates that the HEV isolated from blood donors in the southwest of Iran belongs to genotype 1. However, more samples from other geographic regions of Iran are needed to confirm these findings. Because transmission of HEV by administration of blood or blood components is likely to occur, it may be sensible to screen donor blood for HEV to eliminate transfusion-transmitted HEV infection when the recipient is immunocompromised.

Travel vaccination recommendations and endemic infection risks in solid organ transplantation recipients

BACKGROUND

Solid organ transplant (SOT) recipients are often heavily immunosuppressed and consequently at risk of serious illness from vaccine preventable viral and bacterial infections or with endemic fungal and parasitic infections. We review the literature to provide guidance regarding the timing and appropriateness of vaccination and pathogen avoidance related to the immunological status of SOT recipients.

METHODS

A PUBMED search ([Vaccination OR vaccine] AND/OR ["specific vaccine"] AND/OR [immunology OR immune response OR cytokine OR T lymphocyte] AND transplant was performed. A review of the literature was performed in order to develop recommendations on vaccination for SOT recipients travelling to high-risk destinations.

RESULTS

Whilst immunological failure of vaccination in SOT is primarily the result of impaired B-cell responses, the role of T-cells in vaccine failure and success remains unknown. Vaccination should be initiated at least 4 weeks prior to SOT or more than 6 months post-SOT. Avoidance of live vaccination is generally recommended, although some live vaccines may be considered in the specific situations (e.g. yellow fever). The practicing physician requires a detailed understanding of region-specific endemic pathogen risks.

CONCLUSIONS

We provide a vaccination and endemic pathogen guide for physicians and travel clinics involved in the care of SOT recipients. In addition, recommendations based on timing of anticipated immunological recovery and available evidence regarding vaccine immunogenicity in SOT recipients are provided to help guide pre-travel consultations.

Hepatitis Vaccines

Viral hepatitis is a serious health problem all over the world. However, the reduction of the morbidity and mortality due to vaccinations against hepatitis A and hepatitis B has been a major component in the overall reduction in vaccine preventable diseases. We will discuss the epidemiology, vaccine development, and post-vaccination effects of the hepatitis A and B virus. In addition, we discuss attempts to provide hepatitis D vaccine for the 350 million individuals infected with hepatitis B globally. Given the lack of a hepatitis C vaccine, the many challenges facing the production of a hepatitis C vaccine will be shown, along with current and former vaccination trials. As there is no current FDA-approved hepatitis E vaccine, we will present vaccination data that is available in the rest of the world. Finally, we will discuss the existing challenges and questions facing future endeavors for each of the hepatitis viruses, with efforts continuing to focus on dramatically reducing the morbidity and mortality associated with these serious infections of the liver.

Full coding hepatitis E virus genotype 3 genome amplification method

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A new amplification method for the complete HEV coding genome was described.

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HEV genome organization and function were reviewed.

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Polymorphic amino acids of each HEV genome region were analyzed in reference sequences.

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Complete coding HEV sequence of an immunocompromised patient with acute infection was analyzed.

Hepatitis E virus (HEV) genotype 3 produces zoonotic infection associated with the consumption of infected animals. HEV infections can become chronic in immunocompromised (IC) patients. The viral genome has three well defined open reading frames (ORF1, ORF2 and ORF3) within which various domains and functions have been described. This paper (i) describes a new method of complete sequencing of the HEV coding region through overlapping PCR systems, (ii) establishes a consensus sequence and polymorphic positions (PP) for each domain, and (iii) analyzes the complete coding sequence of an IC patient. With regard to the consensus, a high percentage of PP was observed in protease (PP = 19%) and the X domain (PP = 22%) within ORF1, the N-terminal region of the S domain (PP = 22%) in ORF2, and the P1 (PP = 35%) and P2 (PP = 25%) domains in ORF3. In contrast, the ORF1 Y, ORF2 S, ORF2 M and ORF3 D1 domains were conserved in the reference sequences (0.40, 1, 0.70 and 0% of PP, respectively). The sequence from the IC patient had more mutations in the RpRp (D1235G, Q1242R, S1454T, V1480I, I1502 V, K1511R, G1373 V, E1442D, V1693 M), the terminal ORF2 S- domain (F10L, S26T, G36S, S70P, A105 V, I113 V), the X domain (T938 M, T856 V, S898A) and the helicase (S1014N, S975T, Q1133 K).

Hepatitis E Virus Infection Among Solid Organ Transplant Recipients at a North American Transplant Center

Background.  Autochthonous hepatitis E virus (HEV) infection has been reported in over 200 solid organ transplant (SOT) recipients since 2006, yet little is known about the burden of HEV among SOT recipients in North America. We performed a retrospective, cross-sectional study to investigate the prevalence and risk factors associated with HEV infection among SOT recipients at our institution. Methods.  Children and adults (n = 311) who received allografts between 1988 and 2012 at the Johns Hopkins Hospital were assessed for evidence of HEV infection by testing posttransplantation serum samples for HEV antibody by enzyme immunoassay and HEV RNA by reverse transcription quantitative polymerase chain reaction. Individuals with evidence of posttransplant HEV infection (presence of anti-HEV immunoglobulin [Ig]M antibody, anti-HEV IgG seroconversion, or HEV RNA) were compared with individuals without evidence of infection and assessed for risk factors associated with infection. Results.  Twelve individuals (4%) developed posttransplant HEV infection. Posttransplant HEV infection was associated with an increased risk for graft rejection (odds ratio, 14.2; P = .03). No individuals developed chronic infection. Conclusions.  Solid organ transplant recipients in the United States are at risk for posttransplant HEV infection. Further studies are needed to characterize environmental risk factors and the risk of HEV infection after SOT in North America.

Role of asparagine at position 562 in dimerization and immunogenicity of the hepatitis E virus capsid protein

The hepatitis E virus (HEV) capsid protein, pORF2, contains 2 potential N-glycosylation sites, N137 and N310, located in the S domain, and one site, N562, in the P domain. The last domain located at positions 454-606 aa forms a protruding spike from the shell, with N562 being located in the apical center of the spike, which is also a cell-attachment region and neutralizing antigenic site. Here, we expressed in Pichia pastoris a recombinant polypeptide p179 comprising the region of 439-617 aa of the HEV pORF2 as well as a set of 4 mutant proteins containing substitutions of Q, D, P and Y instead of N at position 562. All proteins were shown to be secreted from yeast. Using SDS-PAGE, Western blot analysis and tunicamycin treatment assay, we showed that the wild-type (wt) protein, p179N562, and 2 mutant variants, p179N562Q and p179N562D, formed homodimers but only the wt protein was shown to be glycosylated. As homodimers, all 3 proteins were immunoreactive with a neutralizing monoclonal antibody (5G5); however, they did not immunoreact with 5G5 after denaturation into monomers. Two other mutant variants, p179N562P and p179N562Y, did not form homodimers but were immunoreactive with the 5G5 antibody. The wt protein was shown to be less immunoreactive with 5G5 than the mutant variants in a double-antibody sandwich ELISA, suggesting a role of glycosylation at N562 in reducing antibody binding. In vitro neutralization experiments showed a more efficient neutralization with mouse antibody against p179N562P and p179N562Y than against the other 3 proteins. These findings indicate that specific substitutions at position 562 have a more measurable effect on the activity of the HEV neutralizing epitope than dimerization or glycosylation of the structural protein. Furthermore, the secretion of monomers fully immunoreactive may call into question the importance of dimerization for an effective presentation of HEV neutralization epitopes.

Epidemiology of Hepatitis E Virus in European Countries

Over the last decade the seroprevalence of immunoglobulin (IgG) anti hepatitis E virus (HEV) has been increasing in European countries and shows significant variability among different geographical areas. In this review, we describe the serological data concerning the general population and risk groups in different European countries. Anti-HEV antibody prevalence ranged from 1.3% (blood donors in Italy) to 52% (blood donors in France). Various studies performed on risk groups in Denmark, Moldova and Sweden revealed that swine farmers have a high seroprevalence of HEV IgG (range 13%-51.1%), confirming that pigs represent an important risk factor in HEV infection in humans. Subtypes 3e,f are the main genotypes detected in the European population. Sporadic cases of autochthonous genotype 4 have been described in Spain, France, and Italy. Although most HEV infections are subclinical, in immune-suppressed and transplant patients they could provoke chronic infection. Fulminant hepatitis has rarely been observed and it was related to genotype 3. Interferon and ribavirin treatment was seen to represent the most promising therapy.

Prevalence and clinical consequences of Hepatitis E in patients who underwent liver transplantation for chronic Hepatitis C in the United States

Background

Infection with hepatitis E virus (HEV) in immunocompromised patients can lead to severe liver disease. Treatment options for HEV include peginterferon or ribavirin, routinely also used for the treatment of hepatitis C virus (HCV) infection.

We determined the prevalence and clinical consequences of HEV in United States (US) based patients who underwent liver transplantation (LT) for chronic HCV.

Methods

Seroprevalence of HEV in 145 US LT recipients with a history of chronic HCV was determined pre-LT, 1, 3 and 5 years post-LT. All last available samples and all samples in IgM positive patients and post-LT IgG seroconverters were tested for HEV RNA.

Results

Overall anti-HEV seroprevalence was 42 %. Five patients were HEV IgM positive pre-LT, one patient had IgM seroconversion post-LT and eight patients had IgG seroconversion post-LT. None of the tested samples were positive for HEV RNA. Eight out of nine of the post-LT seroconverters had been treated for HCV recurrence before or at the moment of seroconversion.

Conclusions

LT recipients in the US are at risk of acquiring HEV. Post-LT HCV treatment with interferons and/or ribavirin may have protected patients against chronic HEV. With the arrival of new direct antiviral agents for the treatment of HCV and the elimination of peginterferon and ribavirin from HCV treatment regimens, the prevalence of chronic HEV in this population may rise again.

Current Knowledge on Hepatitis E

Although only a single serotype of hepatitis E virus (HEV), the causative agent of hepatitis E, has been identified, there is great genetic variation among the different HEV isolates reported. There are at least four major recognized genotypes of HEV: genotypes 1 and 2 are mainly restricted to humans and linked to epidemic outbreaks in nonindustrialized countries, whereas genotypes 3 and 4 are zoonotic in both developing and industrialized countries. Besides human strains, genotype 3 and 4 strains of HEV have been genetically characterized from swine, sika deer, mongooses, sheep, and rabbits. Currently, there are approximately 11,000 human and animal sequences of HEV available at the International Nucleotide Sequence Database Collaboration. HEV is the major cause of waterborne outbreaks of hepatitis in areas of poor sanitation. Additionally, it is responsible for sporadic cases of viral hepatitis in not only endemic but industrialized countries as well. Transmission of HEV occurs predominantly by the fecal-oral route, although parenteral and perinatal routes have been reported. HEV infection develops in most individuals as a self-limiting, acute, icteric hepatitis; with mortality rates around 1%. However, some affected individuals will develop fulminant hepatic failure, a serious condition that is frequently fatal without a liver transplant. This complication is particularly common when the infection occurs in pregnant women, where mortality rates rise dramatically to up to 25%. Among the preventive measures available to avoid HEV infection, two separate subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in the prevention of disease. One of them, HEV 239, was approved in China, and its commercialization by Innovax began in November 2012 under the name Hecolin(®).

Seroprevalence in blood donors reveals widespread, multi-source exposure to hepatitis E virus, southern France, October 2011

The apparent seroprevalence of hepatitis E Virus (HEV) varies greatly among developed countries depending on the geographical area and the sensitivity of immunoassays. We used a validated assay to determine the prevalence of HEV IgG and IgM antibodies among 3,353 blood donors living in southern France, who gave blood during the two first weeks of October 2011 and participated in the study. Demographic and epidemiological information was collected using a specific questionnaire. We also screened 591 samples for HEV RNA. Overall IgG seroprevalence was 39.1% and varied from 20% to 71.3% depending on the geographical area (p?<?0.001) while IgM seroprevalence was 3.31%. Anti-HEV IgG was significantly correlated with increasing age (p?<?0.001), eating uncooked pork liver sausages (p?<?0.001), offal (p?=?0.003), or mussels (p?=?0.02). Anti-HEV IgM was associated with being male (p?=?0.01) and eating uncooked pork liver sausages (p?=?0.02). HEV RNA was detected in one of the 99 anti-HEV IgM-positive samples, but in none of the 492 anti-HEV IgM-negative samples. HEV is hyperendemic in southern France. Dietary and culinary habits alone cannot explain the epidemiology of HEV in this region, indicating that other modes of contamination should be investigated.

Xenotransplantation and Hepatitis E virus

Xenotransplantation using pig cells, tissues and organs may be associated with the transmission of porcine microorganisms to the human recipient. Some of these microorganisms may induce a zoonosis, that is an infectious disease induced by microorganisms transmitted from another species. With exception of the porcine endogenous retroviruses (PERVs), which are integrated in the genome of all pigs, the transmission of all other microorganisms can be prevented by specified or designated pathogen-free (spf or dpf, respectively) production of the animals. However, it is becoming clear in the last years that the hepatitis E virus (HEV) is one of the viruses which are difficult to eliminate. It is important to note that there are differences between HEV of genotypes (gt) 1 and gt2 on one hand and HEV of gt3 and gt4 on the other. HEV gt1 and gt2 are human viruses, and they induce hepatitis and in the worst case fatal infections in pregnant women. In contrast, HEV gt3 and gt4 are viruses of pigs, and they may infect humans, induce commonly only mild diseases, if any, and are harmless for pregnant women. The goal of this review was to evaluate the risk posed by HEV gt3 and gt4 for xenotransplantation and to indicate ways of their elimination from pigs in order to prevent transmission to the human recipient.

Hepatitis viruses and liver transplantation: evolving trends in antiviral management

Viral hepatitis is both a leading indication for liver transplant (LT) and an important cause of posttransplant graft loss and mortality. Treatment and prevention of hepatitis B virus in LT recipients, with the observed corresponding improvement in post-LT outcomes, is among the great success stories in transplantation. By comparison, treatment of hepatitis C virus with safe and effective regimens is only just becoming a reality. Chronic hepatitis E virus infection in LT recipients represents a newly described phenomenon that can also lead to graft loss; early diagnosis and treatment may be key in the management of these patients.

Hepatitis E virus infection

Hepatitis E virus (HEV) infection is a worldwide disease. An improved understanding of the natural history of HEV infection has been achieved within the last decade. Several reservoirs and transmission modes have been identified. Hepatitis E is an underdiagnosed disease, in part due to the use of serological assays with low sensitivity. However, diagnostic tools, including nucleic acid-based tests, have been improved. The epidemiology and clinical features of hepatitis E differ between developing and developed countries. HEV infection is usually an acute self-limiting disease, but in developed countries it causes chronic infection with rapidly progressive cirrhosis in organ transplant recipients, patients with hematological malignancy requiring chemotherapy, and individuals with HIV. HEV also causes extrahepatic manifestations, including a number of neurological syndromes and renal injury. Acute infection usually requires no treatment, but chronic infection should be treated by reducing immunosuppression in transplant patients and/or the use of antiviral therapy. In this comprehensive review, we summarize the current knowledge about the virus itself, as well as the epidemiology, diagnostics, natural history, and management of HEV infection in developing and developed countries.

Chronic hepatitis E: a review of the literature

In 1978, the first case of hepatitis E was identified as non-A, non-B hepatitis. Hepatitis E virus (HEV) infection is believed to be one of the common causes of enterically transmitted acute hepatitis in developing countries and is rare in developed countries, except in patients with a history of travel. However, an increasing number of chronic HEV infection cases have recently been reported in developed countries. In these countries, immunosuppressed patients with HEV infection, such as organ transplant recipients, human immunodeficiency virus (HIV)-infected patients or patients with haematological malignancies, could develop chronic hepatitis E (CHE) infection. Approximately 60% of HEV infections in immunocompromised patients after solid organ transplantation evolve to CHE without antiviral treatment. Clinical manifestations of CHE are often nonspecific symptoms. Many patients with CHE infection are asymptomatic, but some have jaundice, fatigue, abdominal pain, fever and asthenia. Several extrahepatic manifestations have also been reported. Although chronic HEV infection can result in progressive severe liver failure and cirrhosis, diagnosis is often controversial because of the lack of specific diagnostic criteria. Many CHE cases are diagnosed by HEV RNA-positive serum or stool for >6 months. Immunosuppressive drugs, interferon-alpha and ribavirin have been used for treatment. Diagnostic reverse-transcription polymerase chain reaction is useful for estimating treatment efficacy. Preventive measures for HEV infection have been discussed, while systematic guidelines have not yet been reported.

Hepatitis E virus reinfections in solid-organ-transplant recipients can evolve into chronic infections

BACKGROUND

Hepatitis E virus (HEV) infections are a major cause of acute hepatitis in developing and industrialized countries. Little is known about anti-HEV immunity in solid-organ recipients.

METHODS

We screened 263 solid-organ recipients for anti-HEV immunoglobulin G (IgG) at transplantation. They were followed up for 1 year and tested for HEV RNA and anti-HEV antibodies 1 year after transplantation and if their liver enzyme activities increased.

RESULTS

A total of 38.4% had anti-HEV IgG at transplantation. The mean concentrations (±SD) of anti-HEV IgG at transplantation (8 ± 17.5 U/mL) and 1 year later (6.4 ± 12.0 U/mL, P = .4) were similar. There were 3 de novo HEV infections during the 1-year follow-up among patients who were HEV seronegative before transplantation, giving an annual incidence of 2.1%. We also identified 3 HEV reinfections among patients who were seropositive before transplantation through detection of HEV RNA, for an annual incidence of 3.3%. Their anti-HEV IgG concentrations were 0.3, 2.1, and 6.2 World Health Organization (WHO) units/mL before transplantation. Reinfection of the patient with the lowest IgG concentration at transplantation had evolved to a chronic infection.

CONCLUSIONS

Low anti-HEV antibodies (<7 WHO units/mL) seemed not to protect solid-organ recipients. HEV reinfection in immunocompromised patients can lead to chronic infection, as in primary infections.

Hepatitis E: an emerging disease

Currently, the infection with the hepatitis E virus represents the most frequent cause for acute hepatitis and jaundice in the world. According to WHO estimations, around two billion people, representing one third of the world's population, live in endemic areas for HEV and, therefore, are at risk of infection. In developed countries, the circulation of the virus in both human and animal (swine, boar, deer) sewage has been confirmed; however, the incidence rate is low compared to that of developing countries where outbreaks of acute hepatitis transmitted via the fecal-oral route are originated, more frequently in the flooding season or after natural disasters, combined with deficient sanitary conditions. There are currently 4 known genotypes of HEV. Genotypes 1 and 2 are isolated in all human epidemic outbreaks in developing countries, while genotypes 3 and 4 are isolated not only in humans but also in animals, in both developing and industrialized countries. These data support genotypes 3 and 4 having zoonotic nature. The diagnosis of this disease is based in the detection of anti-HEV IgG and IgM in blood serum using enzyme-linked immunosorbent methods. However, the method that best confirms the diagnosis is the RT-PCR, which detects HEV RNA in blood serum and also provides the genotype. The clinical course is generally that of an acute hepatitis which in some cases may require hospitalization and that, in transplant patients or HIV infected individuals can become a chronic hepatitis. Furthermore, the virus constitutes an important risk for pregnant women. The hepatitis E can present a wide range of symptoms, from a subclinical case to chronic liver disease with extrahepatic manifestations. For this reason, the diagnostic is challenging if no differential diagnosis is included. There is no specific antiviral drug for hepatitis E, but satisfactory results have been observed in some patients treated with pegylated interferon alfa2a and/or ribavirin. This revision is an update of all the molecular, epidemiological, clinic and preventive knowledge on this emergent disease up to date.

Hepatitis E virus serological testing in kidney transplant recipients with elevated liver enzymes in 2007-2011 in southeastern France

Hepatitis E virus (HEV) is an emerging cause of acute and chronic hepatitis in Europe, particularly in solid organ transplant recipients. Anti-HEV IgG/IgM testing in kidney transplant recipients with liver biological disturbances indicated high HEV exposure in our geographical area and led to diagnose HEV infection in 6% of cases.

Hepatitis E infection in liver transplant recipients

Hepatitis E virus (HEV) infection (genotype 3) has been described in developed countries as a cause of chronic hepatitis in recipients of solid organ transplantation (SOT), with the first cases reported in 2008. Immunosuppression seems to play a major role in the pathogenesis of chronic infections. The current gold standard for the diagnosis of HEV infection is the detection of HEV RNA in serum, stools, or both. In liver transplant recipients, HEV infection is considered an uncommon disease; however, a high index of suspicion is needed for patients with graft hepatitis of an unclear etiology. Liver transplant recipients seem more likely to develop chronic HEV after an acute infection, and there is accelerated progression to advanced fibrosis and cirrhosis. A decrease in immunosuppression is considered the first line of treatment, and pegylated interferon can be considered the second line of treatment for liver transplant recipients. At the present time, there are not enough data to recommend treatment with ribavirin for adult liver transplant recipients, although this has been tried in other SOT populations.

Antiviral strategies for hepatitis E virus

The hepatitis E virus is a common cause of acute hepatitis. Contrary to hepatitis B and C, hepatitis E is mostly a mild infection, although it has a high mortality in pregnant women and can evolve to chronicity in immunocompromised patients. Ribavirin and pegylated interferon-α are the only available therapies, but both have side effects that are not acceptable for prophylaxis or treatment of mild infections. In addition, these drugs cannot be used for all patient types (e.g. in case of pregnancy, specific organ transplants or co-morbidities) and in resource-poor settings. Hence there is an urgent need for better antiviral treatments that are efficacious and safe, also during pregnancy. In this review, a concise introduction to the virus and disease is provided, followed by a discussion of the available assay systems and potential molecular targets (viral proteins and host factors) for the development of inhibitors of HEV replication. Finally, directions for future research are presented.

Epidemiology, geographical distribution, and economic consequences of swine zoonoses: a narrative review

We sought to review the epidemiology, international geographical distribution, and economic consequences of selected swine zoonoses. We performed literature searches in two stages. First, we identified the zoonotic pathogens associated with swine. Second, we identified specific swine-associated zoonotic pathogen reports for those pathogens from January 1980 to October 2012. Swine-associated emerging diseases were more prevalent in the countries of North America, South America, and Europe. Multiple factors were associated with the increase of swine zoonoses in humans including: the density of pigs, poor water sources and environmental conditions for swine husbandry, the transmissibility of the pathogen, occupational exposure to pigs, poor human sanitation, and personal hygiene. Swine zoonoses often lead to severe economic consequences related to the threat of novel pathogens to humans, drop in public demand for pork, forced culling of swine herds, and international trade sanctions. Due to the complexity of swine-associated pathogen ecology, designing effective interventions for early detection of disease, their prevention, and mitigation requires an interdisciplinary collaborative “One Health” approach from veterinarians, environmental and public health professionals, and the swine industry.

Hepatitis E virus: new faces of an old infection

Hepatitis E virus is one of the most common causes of acute hepatitis worldwide, with the majority of cases occurring in Asia. In recent years, however, an increasing number of acute and chronic hepatitis E virus infections have been reported in industrialized countries. The importance of this infection resides in the associated morbidity and mortality. In acute cases, a high mortality rate has been reported in patients with previously undiagnosed alcoholic liver disease. Hepatitis E infection can become chronic in immunocompromised patients, such as solid organ transplant recipients, patients receiving chemotherapy, and HIV-infected patients, and lead to the development of hepatic fibrosis and cirrhosis. Hence, treatment strategies involving reductions in immunosuppressive regimens and therapy with ribavirin or peg-interferon have been evaluated. In terms of prevention, a promising new vaccine was recently licensed in China, although its efficacy is uncertain and potential adverse effects in risk groups such as chronic liver disease patients and pregnant women require investigation. In conclusion, physicians should be aware of hepatitis E as a cause of both acute and chronic hepatitis in immunocompromised patients. The best treatment option for HEV infection remains to be defined, but both ribavirin and peg-interferon may have a role in therapy for this condition.

Performance of anti-HEV assays for diagnosing acute hepatitis E in immunocompromised patients

Hepatitis E virus is an emerging concern in immunocompromised patients, who may become chronically infected. This prompted us to assess the performance of two anti-HEV IgG and IgM assays for diagnosing acute HEV infections. The specificities of the assays were estimated by testing samples from 2 to 3 year-old French children and blood donors and their sensitivities by testing 40 immunocompromised patients acutely infected. Both anti-HEV IgM assays were highly specific (99.6% and 100%). The sensitivity of the Adaltis was 87.5%, and that of Wantai was 85%. The specificities of anti-HEV IgG Wantai (97.8%) and Adaltis tests (89.5%, p=0.1) were similar but the Wantai test was more sensitive (45%) than the Adaltis test (15%, p<0.001). None of the samples was anti-HEV IgM negative and IgG positive. We conclude that these anti-HEV IgM assays performed well in immunosuppressed subjects with acute hepatitis E and can be used as first line virological tools. Testing for anti-HEV IgG and IgM simultaneously at the acute phase did not improve the diagnostic performance. In contrast, molecular detection of HEV RNA appears essential to exclude an HEV infection in patients who are negative for anti-HEV IgM and to assess the evolution of hepatitis E 3 months thereafter.