Hepatitis E virus as an emerging cause of chronic liver disease in organ transplant recipients

The question of screening organ donors for hepatitis e virus: a case report of transmission by kidney transplantation in France and a review of the literature

BACKGROUND

Hepatitis E is a potentially serious infection in organ recipients, with an estimated two-thirds of cases becoming chronic, and with a subsequent risk of cirrhosis and death. In Europe, transmission occurs most often through the consumption of raw or undercooked pork, more rarely through blood transfusion, but also after solid organ transplantation. Here we describe a case of Hepatitis E virus (HEV) infection transmitted following kidney transplantation and review the literature describing cases of HEV infection transmitted by solid organ transplantation.

CASE PRESENTATION

Three weeks after kidney transplantation, the patient presented with an isolated minimal increase in GGT and hepatic cytolysis 6 months later, leading to the diagnosis of genotype 3c hepatitis E, with a plasma viral load of 6.5 log10IU/mL. In retrospect, HEV RNA was detected in the patient's serum from the onset of hepatitis, and in the donor's serum on the day of donation, with 100% identity between the viral sequences, confirming donor-derived HEV infection. Hepatitis E had a chronic course, was treated by ribavirin, and relapsed 10 months after the end of treatment.

DISCUSSION

Seven cases of transmission of HEV by solid organ transplantation have been described since 2012 without systematic screening for donors, all diagnosed at the chronic infection stage; two patients died. HEV organ donor transmission may be underestimated and there is insufficient focus on immunocompromised patients in whom mild liver function test impairment is potentially related to hepatitis E. However, since HEV infection is potentially severe in these patients, and as evidence accumulates, we believe that systematic screening of organ donors should be implemented for deceased and living donors regardless of liver function abnormalities, as is already the case in the UK and Spain. In January 2024, the French regulatory agency of transplantation has implemented mandatory screening of organ donors for HEV RNA.

The Re-Emergence of Hepatitis E Virus in Europe and Vaccine Development

Hepatitis E virus (HEV) is one of the leading causes of acute viral hepatitis. Transmission of HEV mainly occurs via the fecal-oral route (ingesting contaminated water or food) or by contact with infected animals and their raw meat products. Some animals, such as pigs, wild boars, sheep, goats, rabbits, camels, rats, etc., are natural reservoirs of HEV, which places people in close contact with them at increased risk of HEV disease. Although hepatitis E is a self-limiting infection, it could also lead to severe illness, particularly among pregnant women, or chronic infection in immunocompromised people. A growing number of studies point out that HEV can be classified as a re-emerging virus in developed countries. Preventative efforts are needed to reduce the incidence of acute and chronic hepatitis E in non-endemic and endemic countries. There is a recombinant HEV vaccine, but it is approved for use and commercially available only in China and Pakistan. However, further studies are needed to demonstrate the necessity of applying a preventive vaccine and to create conditions for reducing the spread of HEV. This review emphasizes the hepatitis E virus and its importance for public health in Europe, the methods of virus transmission and treatment, and summarizes the latest studies on HEV vaccine development.

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus-biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Laboratory Diagnosis of HEV Infection

Serological and nucleic acid tests for detecting hepatitis E virus (HEV) have been developed for both epidemiologic and diagnostic purposes. The laboratory diagnosis of HEV infection depends on the detection of HEV antigen or HEV RNA in the blood, stool, and other body fluids, and serum antibodies against HEV (immunoglobulin [Ig]A, IgM, and IgG). Anti-HEV IgM antibodies and low avidity IgG can be detected during the acute phase of the illness and can last approximately 12 months, representing primary infection, whereas anti-HEV IgG antibodies can last more than several years, representing remote exposure. Thus, the diagnosis of acute infection is based on the presence of anti-HEV IgM, low avidity IgG, HEV antigen, and HEV RNA, while epidemiological investigations are mainly based on anti-HEV IgG. Although significant progress has been made in developing and optimizing different formats of HEV assays, improving their sensitivity and specificity, there are many shortcomings and challenges in inter-assay concordance, validation, and standardization. This article reviews the current knowledge on the diagnosis of HEV infection, including the most common available laboratory diagnostic techniques.

High Predictive Power of Meat Juice Serology on the Presence of Hepatitis E Virus in Slaughter Pigs

Hepatitis E virus (HEV) as a zoonotic agent can be responsible for an acute hepatitis in humans, which is usually self-limiting. Progression toward a chronic stage is possible, especially in immunocompromised patients. In the past decade, the number of hepatitis E cases in humans in Germany has increased enormously to 3491 cases in 2018. Domestic pigs have been identified as a main animal reservoir and the consumption of raw and undercooked pork products, that is, livers or liver products, meat or meat products, is known as a potential risk of foodborne HEV infection. The aim of this study was to determine whether serological tests are appropriate to predict the occurrence of HEV in the liver and muscle of domestic pigs in Germany. In 2018, samples of meat juice, liver, and ham muscle were collected from 250 fattening pigs at an abattoir in North West Germany. Samples were analyzed for the presence of HEV antibodies using enzyme-linked immunosorbent assay respectively for the presence of HEV RNA using real-time reverse transcription-polymerase chain reaction. In total, 62% (155/250) of the meat juice samples were positive for HEV antibodies at a single animal basis. At herd level, 72% (18/25) of the herds were seropositive. The HEV prevalence in the liver was 17.2% (43/250). Each positive liver sample originated from seropositive herds respectively from HEV seropositive pigs. This study demonstrates for the first time the significant correlation between a positive HEV serology and the occurrence of HEV RNA in the liver of slaughter pigs (χ² = 31.83; p < 0.001), highlighting the significant predictive power of positive serological results on the occurrence of HEV RNA in the liver.

Clinicopathologic features and pathologic diagnosis of hepatitis E

Infection with the hepatitis E virus (HEV) is one of the most common causes, if not the most common, of acute hepatitis worldwide. In the last decade, we have learned that, in addition to the endemically and epidemically occurring form of hepatitis E, which is predominantly transmitted by contaminated drinking water and constitutes a significant health problem in resource-poor countries, there is a globally existing form of hepatitis E, which is a zoonosis and as such is primarily transmitted by the consumption of contaminated meat products. Although in most cases hepatitis E is subclinical or mild and self-limiting, pregnant women and patients with liver cirrhosis may have severe, occasionally even fatal disease, and immunocompromised individuals may develop chronic hepatitis E. Considering the substantial global health burden caused by HEV infection, it is surprising how limited our knowledge of hepatitis E pathology still is. In this article, we describe localization studies on HEV infection and discuss their implications for everyday diagnostics. Furthermore, we outline and discuss the spectrum of histologic changes, which can be found in HEV infection in various clinical contexts.

Frequency of Hepatotropic Viruses Leading To Deranged Liver Function Tests in Renal Transplant Recipients

OBJECTIVES

The preferred modality for renal replacement therapy is renal transplantation. Marked improvements in early graft survival and long-term graft function have made renal transplantation a more cost-effective alternative to dialysis. The presence of liver disease in the posttransplant period adversely affects graft function and survival. Determining the cause of deranged liver function tests can be helpful in treating the underlying cause, leading to improved graft survival and overall quality of life in patients after renal transplant. Here, we determined the frequency of hepatotropic viral infections leading to deranged liver function tests in renal transplant recipients.

MATERIALS AND METHODS

Our study included 132 patients with deranged liver function tests who had undergone renal transplant within the past 6 months. Reactivity and nonreactivity of hepatotropic viruses leading to deranged liver function tests were recorded.

RESULTS

Average age of patients was 37.17 ± 8.75 years. There were 84 male (63.64%) and 48 female (36.36%) patients. Rates of hepatitis C virus antibodies and hepatitis B surface antigen were 62.88% (83/132) and 37.12% (49/132), respectively, whereas no patients had hepatitis E virus immunoglobulin M antibodies or hepatitis A virus immunoglobulin M antibodies.

CONCLUSIONS

Among the hepatotropic viral infections leading to deranged liver function tests in renal transplant recipients, hepatitis B virus accounted for a small fraction. In contrast, hepatitis C virus was highly prevalent in transplant recipients who developed deranged liver function tests. Renal transplant recipients with hepatic viral infections have worse patient and allograft survival after transplant compared with noninfected renal transplant recipients. We recommend that transplant candidates be screened for hepatitis B and C virus infection, thus allowing increased graft survival and improved quality of life in renal transplant recipients.

Hepatitis E Virus Assembly and Release

Hepatitis E is an underestimated threat to public health, caused by the hepatitis E virus (HEV). HEV is the most common cause of acute viral hepatitis in the world, with no available direct-acting antiviral treatment. According to a recent WHO report, 20 million people become infected with HEV annually, resulting in 44,000 deaths. However, due to the scarcity of efficient in vitro cell culture systems for HEV, our knowledge of the life cycle of HEV is incomplete. Recently, significant progress has been made towards gaining a more comprehensive view of the HEV life cycle, as several in vitro culturing systems have been developed in recent years. Here, we review current knowledge and recent advances with regard to the HEV life cycle, with a particular focus on the assembly and release of viral particles. We also discuss the knowledge gaps in HEV assembly and release. Meanwhile, we highlight experimental platforms that could potentially be utilized to fill these gaps. Lastly, we offer perspectives on the future of research into HEV virology and its interaction with host cells.

Laboratory Diagnosis and Monitoring of Viral Hepatitis

Many microbes, toxins, autoimmune diseases, and neoplastic diseases may cause liver inflammation; however, 5 viruses whose main pathogenesis is liver disease are referred to as hepatitis A, B, C, D, and E viruses. These viruses cause a significant burden of global illness. With the exception of hepatitis A virus, all may cause chronic infection potentially leading to cirrhosis and hepatocellular carcinoma. Excellent serologic and nucleic acid detection methods are available for determining the precise cause and, in some cases, the duration of infection. Diagnostics are critical for identifying individuals needing treatment and for monitoring the treatment success.

Prevalence of active hepatitis E virus infection and efficacy of ribavirin treatment in renal allograft recipients

BACKGROUND

Hepatitis E virus (HEV) genotype 3 infection frequently progresses to chronic disease with persisting HEV viremia in immunocompromised patients. Here, we evaluated the prevalence of HEV infection in renal allograft recipients and investigated the efficacy and tolerability of ribavirin monotherapy.

METHODS

A total of 947 recipients on average 8.7 years post transplant were screened for anti-HEV IgG, IgM and HEV-RNA. Sixteen HEV-viremic renal allograft recipients were treated with ribavirin for 12 weeks. HEV-RNA concentration, laboratory and clinical parameters were assessed at baseline, during therapy and 12 weeks after treatment cessation. HEV-genotyping was performed in all HEV-viremic patients.

RESULTS

Past HEV infection was detected serologically in 18% of the renal allograft recipients. Ongoing HEV replication was found in 16 recipients (all genotype 3). Unanimously, distinct HEV sequences were revealed in all HEV-viremic patients. At the start of ribavirin treatment, median HEV-RNA viral load was 4.3 × 10⁶ (8000-5.0 × 10⁶ ) IU/mL. Ninety-four percentage of HEV-infected allograft recipients showed a sustained virological response 12 weeks after treatment cessation. Ribavirin treatment was associated with rapid decrease in liver enzymes and rare occurrence of anemia.

CONCLUSIONS

Prevalence of active HEV infection is important in renal transplant patients without signs of nosocomial infection. Ribavirin treatment was safe and effective.

Hepatitis E virus seroprevalence among blood donors in Pune, India

BACKGROUND

Blood transfusion is a recently reported route of hepatitis E virus (HEV) transmission. It is a bigger concern in regions where large-scale HEV genotype 1 infections occur causing more severe disease. The present study aims to assess the prevalence and rate of HEV infection in the blood donors of Pune, India.

MATERIALS AND METHODS

A total of 2447 healthy blood donors were screened for anti-HEV IgG and IgM antibodies. Anti-HEV IgM antibody positives were further subjected to alanine aminotransferase measurement, HEV RNA detection, viral load quantification and phylogenetic analysis.

RESULTS

Anti-HEV seroprevalence rate was 17.70%, while IgM prevalence rate was 0.20%. An age dependent increase in IgG seropositive rate was observed. Two of five IgM-positives tested positive for HEV RNA. The viral load ranged from 3.5 × 10⁴ to 4.6 × 10⁵ copies/mL and belonged to HEV genotype 1.

CONCLUSIONS

HEV prevalence rate of 17.70% in the blood donors of Pune, India, a developing country, goes at par with the developed countries. Current data of 0.20% (5 of 2447) blood donors positive for anti-HEV IgM and two of them being HEV RNA positive suggest a need for consideration of cost-effective evaluation towards pooled HEV RNA testing in blood banks.

Molecular and serological infection marker screening in blood donors indicates high endemicity of hepatitis E virus in Poland

BACKGROUND

Until now, markers of hepatitis E virus (HEV) infection have not been studied in blood donors throughout Poland, and no acute case of HEV infection has been closely documented or confirmed by HEV RNA detection. The prevalence of HEV infection markers, including HEV RNA in Polish blood donors and virus genotypes was investigated.

STUDY DESIGN AND METHODS

In total, 12,664 individual donations from 22 Polish blood transfusion centers were tested for HEV RNA by transcription-mediated amplification. In addition, 3079 first-time donors sampled throughout Poland also were screened for antibodies to HEV. HEV RNA and immunoglobulin M-positive donations were confirmed using real-time reverse transcription-polymerase chain reaction and Western blotting, respectively.

RESULTS

Ten donors were identified as RNA initial reactive (one of 1266 donors), and six (one of 2109) were identified as repeat reactive and confirmed by real-time reverse transcription-polymerase chain reaction or seroconversion. Sequence analysis identified HEV Genotype 3c in one donor and Genotype 3i in two others. On average, 43.5% of donors were immunoglobulin G-positive. Immunoglobulin G seroprevalence ranged from 22.7% to 60.8% in group ages 18 to 27 years and 48 to 57 years, respectively and differed between administrative regions from 28.9% in Podlasie to 61.3% in Wielkopolska. Thirty-nine of the donors were immunoglobulin M-positive, and seven donors were IgM positive only (0.2%). Of 37 immunoglobulin M-reactive samples tested by Western blot, 24 (64.9%) were confirmed.

CONCLUSIONS

The current results indicate a high level of HEV endemicity throughout Poland compared with other countries. There is an urgent need to consider the protection of recipients of blood components against transfusion-transmitted HEV infection.

The divergence of epidemiological, antigenic and immunogenic characteristics of hepatitis E virus of different genotypes

Hepatitis E virus (HEV) is an enterically transmitted pathogen that causes hepatitis E (HE). HEVs infecting mammals have been classified into four genotypes. Numerously diverse behaviors have been found among HEV genotypes; the first two genotypes are endemic in developing countries and only infect humans, whereas genotypes 3 and 4 infect other mammalian species as well. It is still unclear why only HEV genotypes 3 and 4 can infect across species. This article comprehensively: reviews the divergence of epidemiological and immunogenic characteristics of HEV infection derived from different genotypes; provides the current knowledge on the antigenic and immunogenic differences between different HEV genotypes; and will give useful information on serological diagnosis development and vaccines preparation.

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically only seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Laboratory Diagnosis of HEV Infection

Serological and nucleic acid tests for detecting hepatitis E virus (HEV) have been developed for both epidemiologic and diagnostic purposes. The laboratory diagnosis of HEV infection depends on the detection of HEV antigen, HEV RNA, and serum antibodies against HEV (immunoglobulin [Ig]A, IgM, and IgG). Anti-HEV IgM antibodies can be detected during the acute phase of the illness and can last approximately 4 or 5 months, representing recent exposure, whereas anti-HEV IgG antibodies can last more than 10 years, representing remote exposure. Thus, the diagnosis of acute infection is based on the presence of anti-HEV IgM, HEV antigen, and HEV RNA, while epidemiological investigations are mainly based on anti-HEV IgG. Although significant progress has been made in developing and optimizing different formats of HEV assays, improving their sensitivity and specificity, there are many shortcomings and challenges in inter-assay concordance, validation, and standardization. This article reviews the current knowledge on the diagnosis of HEV infection, including the most common available laboratory diagnostic techniques.

Pig model mimicking chronic hepatitis E virus infection in immunocompromised patients to assess immune correlates during chronicity

Chronic hepatitis E virus (HEV) infection is a significant clinical problem in immunocompromised individuals such as organ transplant recipients, although the mechanism remains unknown because of the lack of an animal model. We successfully developed a pig model of chronic HEV infection and examined immune correlates leading to chronicity. The conditions of immunocompromised patients were mimicked by treating pigs with an immunosuppressive regimen including cyclosporine, azathioprine, and prednisolone. Immunocompromised pigs infected with HEV progressed to chronicity, because 8/10 drug-treated HEV-infected pigs continued fecal virus shedding beyond the acute phase of infection, whereas the majority (7/10) of mock-treated HEV-infected pigs cleared fecal viral shedding at 8 wk postinfection. During chronic infection, serum levels of the liver enzyme γ-glutamyl transferase and fecal virus shedding were significantly higher in immunocompromised HEV-infected pigs. To identify potential immune correlates of chronic infection, we determined serum levels of cytokines and cell-mediated immune responses in pigs. Results showed that HEV infection of immunocompromised pigs reduced the serum levels of Th1 cytokines IL-2 and IL-12, and Th2 cytokines IL-4 and IL-10, particularly during the acute phase of infection. Furthermore IFN-γ-specific CD4⁺ T-cell responses were reduced in immunocompromised pigs during the acute phase of infection, but TNF-α-specific CD8⁺ T-cell responses increased during the chronic phase of infection. Thus, active suppression of cell-mediated immune responses under immunocompromised conditions may facilitate the establishment of chronic HEV infection. This pig model will aid in delineating the mechanisms of chronic HEV infection and in developing effective therapeutics against chronic hepatitis E.

Hepatitis E Virus and the Liver: Clinical Settings and Liver Pathology

Infection with hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide, now increasingly recognized also in nonendemic regions. Clinical manifestation of hepatitis E includes mostly asymptomatic/subclinical presentations or acute, self-limiting hepatitis, but also potentially fatal liver failure or chronic hepatitis in immunocompromised individuals. Accordingly, hepatitis E histolpathologic patterns range from an unremarkable histology over acute (cholestatic) hepatitis with variable degree of necrosis to chronic hepatitis with fibrosis. Awareness of hepatitis E and its differential diagnoses, knowledge of its clinico-pathologic manifestations and familiarity with its diagnostic tools will enable clinicians and pathologists to competently make this diagnosis.

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.

Characterization of the Specificity, Functionality, and Durability of Host T-Cell Responses Against the Full-Length Hepatitis E Virus

The interplay between host antiviral immunity and immunopathology during hepatitis E virus (HEV) infection determines important clinical outcomes. We characterized the specificity, functionality, and durability of host T-cell responses against the full-length HEV virus and assessed a novel "Quantiferon" assay for the rapid diagnosis of HEV infection. Eighty-nine volunteers were recruited from Oxford, Truro (UK), and Toulouse (France), including 44 immune-competent patients with acute HEV infection, 18 HEV-exposed immunosuppressed organ-transplant recipients (8 with chronic HEV), and 27 healthy volunteers. A genotype 3a peptide library (616 overlapping peptides spanning open reading frames [ORFs] 1-3) was used in interferon-gamma (IFN-γ) T-cell ELISpot assays. CD4⁺ /CD8⁺ T-cell subsets and polyfunctionality were defined using ICCS and SPICE analysis. Quantification of IFN-γ used whole-blood stimulation with recombinant HEV-capsid protein in the QuantiFERON kit. HEV-specific T-cell responses were detected in 41/44 immune-competent HEV exposed volunteers (median magnitude: 397 spot-forming units/10⁶ peripheral blood mononuclear cells), most frequently targeting ORF2. High-magnitude, polyfunctional CD4 and CD8⁺ T cells were detected during acute disease and maintained to 12 years, but these declined over time, with CD8⁺ responses becoming more monofunctional. Low-level responses were detectable in immunosuppressed patients. Twenty-three novel HEV CD4⁺ and CD8⁺ T-cell targets were mapped predominantly to conserved genomic regions. QuantiFERON testing demonstrated an inverse correlation between IFN-γ production and the time from clinical presentation, providing 100% specificity, and 71% sensitivity (area under the receiver operator characteristic curve of 0.86) for HEV exposure at 0.3 IU/mL.

CONCLUSION

Robust HEV-specific T-cell responses generated during acute disease predominantly target ORF2, but decline in magnitude and polyfunctionality over time. Defining HEV T-cell targets will be important for the investigation of HEV-associated autoimmune disease. (Hepatology 2016;64:1934-1950).

Chronic hepatitis E: A brief review

Hepatitis E viral infection has traditionally been considered an acute, self-limited, water borne disease similar to hepatitis A, endemic to developing countries. However, over the past decade, zoonotic transmission and progression to chronicity in human patients has been identified, resulting in persistently elevated transaminase levels, progressive liver injury and cirrhosis. In addition to liver injury, neurological, renal and rheumatological manifestations have also been reported. Chronic hepatitis E occurs mainly in immunosuppressed individuals such as transplant recipients, human immunodeficiency virus patients with low CD4 counts and in patients with hematological malignancies receiving chemotherapy. Diagnosis is established by persistent elevation of hepatitis E virus RNA in the stool or serum. This population often requires treatment with antiviral agents, particularly ribavirin, as spontaneous clearance with reduction in immunosuppression occurs only in about a third of the patients. The purpose of this review, is to further discuss the clinical presentation, and recent advances in diagnosis, treatment and prophylaxis of chronic hepatitis E.

The emergence of hepatitis E virus in Europe

ABSTRACT 

Hepatitis E virus (HEV) infections appear to be an emerging problem in Europe. Infections are mainly caused by viruses of genotype 3. Pigs and wild boar are the main reservoirs of HEV in Europe and most autochthonous infections are probably caused by the consumption of uncooked or undercooked infected meat. Nevertheless, transfusion-associated transmission has been described in different European countries but the efficiency of this route of transmission need to be further investigated. Most acute infections are asymptomatic or the induced symptoms are rather nonspecific. Although people that are otherwise completely healthy can spontaneously clear an HEV infection, people with underlying liver disease and/or suffering from immune deficiencies may require treatment to avoid chronicity and exacerbation of liver disease. In this review, we give an epidemiological overview of HEV in Europe and the potential complications.

Hepatitis E in hemodialysis and kidney transplant patients in south-east Italy

AIM: To investigate the serovirological prevalence and clinical features of hepatitis E virus (HEV) infection in end-stage renal failure patients and in the healthy population.

METHODS: HEV infection is a viral disease that can cause sporadic and epidemic hepatitis. Previous studies unexpectedly showed a high prevalence of HEV antibodies in immunosuppressed subjects, including hemodialysis (HD) patients and patients who had undergone kidney transplant. A cohort/case-control study was carried out from January 2012 to August 2013 in two hospitals in southern Italy (Foggia and S. Giovanni Rotondo, Apulia). The seroprevalence of HEV was determined in 801 subjects; 231 HD patients, 120 renal transplant recipients, and 450 health individuals. All HD patients and the recipients of renal transplants were attending the Departments of Nephrology and Dialysis at two hospitals located in Southern Italy, and were included progressively in this study. Serum samples were tested for HEV antibodies (IgG/IgM); in the case of positivity they were confirmed by a Western blot assay and were also tested for HEV-RNA, and the HEV genotypes were determined.

RESULTS: A total of 30/801 (3.7%) patients were positive for anti-HEV Ig (IgG and/or IgM) and by Western blot. The healthy population presented with a prevalence of 2.7%, HD patients had a prevalence of 6.0%, and transplant recipients had a prevalence of 3.3%. The overall combined HEV-positive prevalence in the two groups with chronic renal failure was 5.1%. The rates of exposure to HEV (positivity of HEV-IgG/M in the early samples) were lower in the healthy controls, but the difference among the three groups was not statistically significant (P > 0.05). Positivity for anti-HEV/IgM was detected in 4/30 (13.33%) anti-HEV Ig positive individuals, in 2/14 HD patients, in 1/4 transplant individuals, and in 1/12 of the healthy population. The relative risk of being HEV-IgM-positive was significantly higher among transplant recipients compared to the other two groups (OR = 65.4, 95%CI: 7.2-592.7, P < 0.001), but the subjects with HEV-IgM positivity were numerically too few to calculate a significant difference. No patient presented with chronic hepatitis from HEV infection alone.

CONCLUSION: This study indicated a higher, but not significant, circulation of HEV in hemodialysis patients vs the healthy population. Chronic hepatitis due to the HEV virus was not observed.

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.

Phylogenetic demonstration of hepatitis E infection transmitted by pork meat ingestion

Hepatitis E virus (HEV) is responsible for a small number of acute hepatitis in developed countries. In this setting, HEV infection seems to be a zoonosis, although this has not been completely demonstrated. High morbidity and mortality associated with severe acute infections have been described, as well as the possible role of ribavirin therapy in those cases. We describe a case of acute hepatitis after pork meat ingestion in a patient with Waldeström macroglobulinemia with immunoglobulin A deficiency. Acute hepatitis E was diagnosed based on positive IgM anti-HEV antibodies and HEV RNA detected by real-time PCR. Because of clinical and analytical worsening, ribavirin was initiated, achieving sustained virologic response after 12 weeks of treatment. The phylogenetic analysis revealed the same HEV strain genotype 3 in both plasma and consumed meat samples, proving the zoonotic transmission. Regarding immunocompromised patients, acute hepatitis E can be associated to high morbidity and mortality rate, so dietetic recommendations may be needed to avoid the virus transmission.

Comparison of real-time PCR and antigen assays for detection of hepatitis E virus in blood donors

Hepatitis E virus (HEV) infection is recognized as an emerging and often undiagnosed disease in industrialized countries, with asymptomatic infections actually occurring in blood donors. Sensitive detection of HEV-RNA is crucial for diagnosis and monitoring of disease progression. We evaluated the analytical sensitivity and performance of three HEV RT-PCR assays (RealStar HEV reverse transcription-PCR [RT-PCR], hepatitis@ceeramTools, and ampliCube HEV RT-PCR) for screening of individuals for HEV infections (ID-nucleic acid amplification technology [ID-NAT]) and for blood donor pool screening (minipool-NAT [MP-NAT]). RNA was extracted using NucliSens easyMAG (ID-NAT) and a high-volume extraction protocol (4.8 ml, chemagic Viral 5K, MP-NAT). Three NAT assays were evaluated for ID-NAT but only two assays for MP-NAT due to inhibition of the ampliCube HEV RT-PCR kit using the corresponding RNA extract. Assays provided good analytical sensitivity, ranging from 37.8 to 180.1 IU/ml (ID-NAT) and from 4.7 to 91.2 IU/ml (MP-NAT). The applicability of HEV antigen (HEV-Ag) screening was compared to that of RT-PCR screening and detection of HEV-IgM antibodies using seroconversion panels of 10 HEV genotype 3-infected individuals. Four individuals revealed a positive HEV-Ag detection result, with corresponding viremias ranging from 1.92 E + 03 to 2.19 E + 05 IU/ml, while the progression of HEV-Ag followed that of HEV viremia. The other six individuals showed no presence of HEV-Ag although the corresponding viremias were also in the range of >1.0 E + 03. Anti-HEV-IgM antibodies were detectable in seven donors; one donor presented parallel positivities of HEV-Ag and anti-HEV IgM. The evaluated NAT methods present powerful tools providing sensitive HEV detection. Application of HEV-Ag or anti-HEV IgM screening is currently inferior for the early detection of HEV infection due to the decreased sensitivity compared to NAT methods.

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.

Autochthonous hepatitis e virus infections: a new transfusion-associated risk?

Hepatitis E virus (HEV) has been recognized since 2004 as a transfusion-transmissible infectious agent, and recent epidemiological data suggest that it may pose a safety threat to the blood supply. It has recently become obvious that hepatitis E is endemic in industrialized countries, and that more infections are autochthonous than travel-associated. Epidemiological and phylogenetic analysis suggests that HEV infection has to be considered as a zoonosis and that viral transmission from animals (pigs, wild animals) occurs through food or direct contact. The seroprevalence and incidence of HEV in the general population and blood donors in European countries indicate an underestimated risk for transfusion transmissions. Recently reported cases of transfusion transmission of HEV infection, and detection of viremic, asymptomatic blood donors in nucleic acid amplification technique screening programs give an indication of the importance of this virus. Diagnostic assays for detection of anti-HEV antibodies, HEV antigens and RNA are discussed. Recent studies support the idea that active immunization can prevent hepatitis E, highlighting the need for vaccination programs. Here we review current knowledge of HEV and its epidemiology, blood transmission and prevention of this disease with emphasis on blood supply.

Protective immunity against HEV

Rural community of Dongtai City in eastern China is endemic for hepatitis E virus (HEV), with the zoonotic genotype 4 virus predominating. The virus appears to be widely distributed in environment at generally low levels, such that infection is common, but >97% of which are asymptomatic and provoke a modest antibody response. Naturally acquired immunity affords 75% protection against infection, prevents disease caused by primary infection and alleviates severity of the disease caused by the residual infection that had evaded host immune surveillance. The protection, however, is extended to a minority, while leaving the majority of population essentially without the benefits of immune protection. Vaccination affords similar level of protection as does natural immunity, but expands the protective coverage to the entire population.

Hepatitis E virus infections in HIV-infected patients in Ghana and Cameroon

BACKGROUND

Chronic hepatitis E virus (HEV) infections have recently been described in HIV-infected patients. Only few data are available for sub-Saharan Africa, where HIV and HEV are highly co-endemic, and where liver pathology is common in HIV-infected individuals.

OBJECTIVES

To assess the prevalence of HEV viremia, anti-HEV antibodies, and serum aminotransferase levels in HIV patients in Ghana and Cameroon.

STUDY DESIGN

We retrospectively surveyed a cross-section of patients who were enrolled in cohort studies in Ghana (West Africa), and Cameroon (Central Africa). Plasma samples from 1029 HIV patients from Ghana and 515 patients from Cameroon including 214 children were analyzed for HEV-RNA by two reverse transcription PCR methods. In a subset of 791 patients, anti-HEV IgG and IgM antibodies were analyzed.

RESULTS

No HEV-RNA was detected in any of the plasma samples of 1544 patients. HEV seroprevalence was high in adult HIV patients from Ghana (45.3%, n=402) and Cameroon (14.2%, n=289), but low in pediatric HIV patients from Cameroon (2.0%, n=100). Elevations of alanine aminotransferase and aspartate aminotransferase levels were common in adult patients from Ghana (20.8% and 25.4%) and Cameroon (38.9% and 69.8%). The prevalence of hepatitis B virus surface antigen was 11.8% and of hepatitis C virus antibodies 2.5% in our adult Cameroonian study population.

CONCLUSIONS

Acute or chronic HEV infections did not play a role in liver pathology in two HIV cohorts in Ghana and Cameroon. A better understanding of the epidemiology and genotype-specific characteristics of HEV infections in HIV patients in sub-Saharan Africa is needed.

Chronic hepatitis e virus infection and treatment

It is now well accepted that hepatitis E virus (HEV) infection can induce chronic hepatitis and cirrhosis in immunosuppressed patients. Chronic genotype-3 HEV infections were first reported in patients with a solid-organ transplant. Thereafter, cases of chronic HEV infection have been reported in patients with hematological disease and in those who are human immunodeficiency virus (HIV)-positive. HEV-associated extra-hepatic manifestations, including neurological symptoms, kidney injuries, and hematological disorders, have been also reported. In transplant patients, reducing the dosage of immunosuppressive drugs allows the virus to be cleared in some patients. In the remaining patients, as well as hematological patients and patients who are HIV-positive, anti-viral therapies, such as pegylated interferon and ribavirin, have been found to be efficient in eradicating HEV infection. This review summarizes our current knowledge of chronic HEV infection, its treatment, and the extra-hepatic manifestations induced by HEV.

Chronic hepatitis E infection: risks and controls

Very recently, an unusual clinical presentation with an altered natural history associated with hepatitis E virus (HEV) infection has emerged in high-income industrialized nations. Although HEV infection does not develop into chronicity in general, viremia can persist for long periods of time in immunocompromised solid organ, bone marrow and stem cell transplant patients. Conceivably, the atypical clinical and virological outcomes in these cases could be related to immunosuppressive chemotherapy, resulting in suboptimal HEV-specific immune responses. In the absence of travel to endemic regions, foodborne autochthonous HEV infection due to viral genotypes 3 and 4 has been implicated in the chronic cases. Presently, pegIFN-α-2a and ribavirin, the commonly used drugs to treat chronic viral hepatitis, are proving very promising in hepatitis E patients. Nevertheless, the most-awaited HEV vaccine could be protective in naïve travelers or high-risk group populations. The mechanisms of establishing chronic HEV infection and the disease severity have hitherto not been clearly understood. Therefore, a comprehensive clinical, virological and molecular study is needed to understand and control the disease.

Hepatitis E: source and route of infection, clinical manifestations and new developments

Hepatitis E was previously thought to be a disease of developing countries causing significant morbidity and mortality in young adults, particularly among pregnant women and patients with pre-existing chronic liver disease. Recent studies have shown that hepatitis E is also an issue in developed countries. In this setting, hepatitis E is a zoonotic infection and causes acute infection mainly in middle-aged and elderly men; and chronic infection in the immunosuppressed. The scope and burden of disease are still emerging. The diagnosis of hepatitis E should be considered in any patient with hepatitis, irrespective of their age or travel history.

Infection with hepatitis E virus in kidney transplant recipients in southeastern France

Hepatitis E virus (HEV) is an emerging cause of acute hepatitis in Europe, particularly in southern France, and HEV is a new causative agent of chronic hepatitis and cirrhosis in immunocompromised patients. However, the data regarding HEV infection after kidney transplantation are still scarce with respect to the clinical issues that have been raised, and no study has specifically focused on kidney transplant recipients. This study described the clinical features and outcomes of HEV infections in a cohort of kidney transplant recipients living in southeastern France. The epidemiological, clinical, and virological characteristics of HEV infections diagnosed by PCR over a 53-month period were retrospectively analyzed in a cohort of 1,350 kidney transplant recipients monitored at the Marseille University Hospital. Sixteen HEV infections were diagnosed, all of which were autochthonous and involved genotype 3 viruses (HEV-3). Chronic infections occurred in 80% of these patients and resolved in half of the cases after a median time of 39 months. The rate of HEV clearance was 54% after a decrease in the dose of immunosuppressants. One patient developed liver cirrhosis 14 months after infection and experienced acute rejection after a decrease in the dose of immunosuppressants. Autochthonous HEV-3 infections in kidney transplant recipients progress to chronicity in most cases and might be complicated by early liver cirrhosis. Chronic HEV infection can resolve following the reduction of immunosuppressive therapy, but ribavirin may be required if reduction of the immunosuppressant dose is not associated with HEV clearance or is inappropriate for the patient management.

[Hepatitis E: molecular virology, epidemiology and pathogenesis]

Hepatitis E represents a significant proportion of enteric transmitted liver diseases and poses a major public health problem, mainly associated with epidemics due to contamination of water supplies, especially in developing countries. Hepatitis E virus (HEV) is responsible for self-limiting acute liver oral-faecal infections. In industrialised countries, acute hepatitis E is sporadic, detected in travellers from endemic areas but also in sporadic cases with no risk factors. HEV is a non-enveloped virus with a single-stranded RNA genome classified into 4 genotypes and a single serotype. Genotypes 1 and 2 only infect humans, and are predominant in the developing countries, while 3 and 4 are predominant in industrialised countries, and also infect other species of mammals, especially pigs, and multiple evidence classifies HEV as a zoonotic agent. Some HEV chronic infections have recently been reported in kidney and liver transplant patients. The mortality rate of HEV infection is greater than hepatitis A. In addition to faecal-oral transmission, parenteral transmission of HEV has also been reported. Several vaccines are currently in development. The severity of this infection in some groups of patients, especially pregnant women, and the occurrence of chronic hepatitis, even with progression to cirrhosis, have raised interest in the application of interferon and/or ribavirin therapy.

[Hepatitis E: scale of the problem in Spain]

Hepatitis E virus (HEV) infection is one of the most frequent causes of acute hepatitis worldwide. However, in Spain, HEV causes only a tiny number of cases of acute hepatitis, the most prevalent cause being hepatitis A. Most cases of HEV in Spain are "imported", being acquired through travel to areas where this infection is endemic. Nevertheless, in the last few years a growing number of "autochthonous cases" have been reported in persons with no history of travelling to HEV-endemic areas. The prevalence of IgG antibodies against HEV, indicating exposure to this virus, is approximately 0.6-7.3% in the general population in Spain and is 19% in persons with risk factors such as exposure to pigs.

Hepatitis E seroprevalence in recipients of renal transplants or haemodialysis in southwest England: a case-control study

Locally acquired HEV infection is increasingly recognized in developed countries. Anti-HEV IgG seroprevalence has been shown to be high in haemodialysis patients in a number of previous studies, employing assays of uncertain sensitivity. The aim of this study was to investigate anti-HEV IgG seroprevalence in recipients of haemodialysis and renal transplants compared to a control group using a validated, highly sensitive assay. Eighty-eight patients with functioning renal transplants and 76 receiving chronic haemodialysis were tested for HEV RNA and anti-HEV IgG and IgM. Six hundred seventy controls were tested for anti-HEV IgG. Anti-HEV IgG was positive in 28/76 (36.8%) of haemodialysis and 16/88 (18.2%) of transplant patients. HEV RNA was not found in any patient. 126/670 (18.8%) of control subjects were anti-HEV IgG positive. After adjusting for age and sex, there was a significantly higher anti-HEV IgG seroprevalence amongst haemodialysis patients compared to controls (OR = 1.97, 95% CI = 1.16-3.31, P = 0.01) or transplant recipients (OR = 2.63, 95% CI = 1.18-6.07, P = 0.02). Patients with a functioning transplant showed no difference in anti-HEV IgG seroprevalence compared to controls. The duration of haemodialysis or receipt of blood products were not significant risk factors for HEV IgG positivity. Patients receiving haemodialysis have a higher seroprevalence of anti-HEV IgG than both age- and sex-matched controls and a cohort of renal transplant patients. None of the haemodialysis patients had evidence of chronic infection. The reason haemodialysis patients have a high seroprevalence remains uncertain and merits further study.

Emerging viral diseases in kidney transplant recipients

Viruses are the most important cause of infections and a major source of mortality in Kidney Transplant Recipients (KTRs). These patients may acquire viral infections through exogenous routes including community exposure, donor organs, and blood products or by endogenous reactivation of latent viruses. Beside major opportunistic infections due to CMV and EBV and viral hepatitis B and C, several viral diseases have recently emerged in KTRs. New medical practices or technologies, implementation of new diagnostic tools, and improved medical information have contributed to the emergence of these viral diseases in this special population. The purpose of this review is to summarize the current knowledge on emerging viral diseases and newly discovered viruses in KTRs over the last two decades. We identified viruses in the field of KT that had shown the greatest increase in numbers of citations in the NCBI PubMed database. BKV was the most cited in the literature and linked to an emerging disease that represents a great clinical concern in KTRs. HHV-8, PVB19, WNV, JCV, H1N1 influenza virus A, HEV, and GB virus were the main other emerging viruses. Excluding HHV8, newly discovered viruses have been infrequently linked to clinical diseases in KTRs. Nonetheless, pathogenicity can emerge long after the discovery of the causative agent, as has been the case for BKV. Overall, antiviral treatments are very limited, and reducing immunosuppressive therapy remains the cornerstone of management.

Prevalence of hepatitis E virus infection in pediatric solid organ transplant recipients--a single-center experience

HEV infection appears to be an emerging disease in industrialized countries. The aim of this study was to evaluate the prevalence of HEV infection in pediatric solid organ transplant recipients. One hundred and twenty-four pediatric recipients of liver (n = 41) or kidney (n = 83) transplants aged between one and 18 yr were screened for anti-HEV IgG antibodies. Patients were tested for fecal HEV RNA excretion if they showed anti-HEV seropositivity. As a control group, 108 immunocompetent pediatric patients without liver disease aged between three and 18 yr were screened for anti-HEV IgG. HEV seroprevalence was 2.4% in renal Tx (2/83), 4.9% in liver Tx patients (2/41), and 3.2% overall (4/124). Three of these four patients were HEV RNA-negative. In one renal transplant patient, HEV genotype 3 RNA excretion persisted and liver enzymes were elevated, indicating chronic hepatitis. In the control group, eight patients (7.4%) were HEV IgG-positive without biochemical evidence of hepatitis. The prevalence of HEV infection in pediatric renal or liver transplant recipients is not higher compared with immunocompetent children. Chronic HEV infection with long-term carriage of the virus may develop in pediatric transplant recipients. Autochthonous HEV infection needs to be considered in uncertain cases of hepatitis in immunosuppressed as well as immunocompetent children.

Discrepancy between anti-hepatitis E virus immunoglobulin G prevalence assessed by two assays in kidney and liver transplant recipients

BACKGROUND

Hepatitis E virus (HEV) is an emerging clinical threat in Europe among kidney and liver-transplant recipients. The incidence and prevalence of HEV infection in this special population are poorly known. False-negative results have been observed for anti-HEV IgG detection in severely immunocompromized persons. Moreover, large discrepancies have been reported between rates of anti-HEV IgG detection in blood donors and hepatitis E cases.

OBJECTIVES

To compare anti-HEV IgG and IgM prevalence using two different commercial microplate enzyme-immuno assays (MEIAs) (Adaltis and Wantai) in 64 kidney-/liver-transplant recipients.

STUDY DESIGN

Serum samples tested in our routine clinical practice over the 12/2009-12/2011 period with Adaltis MEIAs were retrospectively tested using Wantai MEIAs. IgG-positive sera were further tested by an immunoblot while those found IgM-positive were further tested with an immunochromatography rapid test and for the presence of HEV RNA.

RESULTS

Positive results on anti-HEV IgG testing were obtained for seven (10.9%) compared to 20 (31.3%) serum samples with Adaltis and Wantai assays, respectively (p=0.005). Then, 6/7 (86%) of the serum samples positive with Adaltis and 16/20 (80%) of those positive with Wantai were positive with the immunoblot. One patient with chronic HEV infection was IgG-negative with both MEIAs. Regarding anti-HEV IgM, Adaltis and Wantai assays were concordant for 97% of the serum samples, prevalence being 8% with both MEIAs.

CONCLUSIONS

The accuracy of currently available commercial or in-house anti-HEV IgG MEIAs should be tested comparatively on a panel of serum samples collected from solid organ-transplant recipients, including some who experienced PCR-documented HEV infection.

Hepatitis E

Hepatitis E virus (HEV) was discovered during the Soviet occupation of Afghanistan in the 1980s, after an outbreak of unexplained hepatitis at a military camp. A pooled faecal extract from affected soldiers was ingested by a member of the research team. He became sick, and the new virus (named HEV), was detected in his stool by electron microscopy. Subsequently, endemic HEV has been identified in many resource-poor countries. Globally, HEV is the most common cause of acute viral hepatitis. The virus was not initially thought to occur in developed countries, but recent reports have shown this notion to be mistaken. The aim of this Seminar is to describe recent discoveries regarding HEV, and how they have changed our understanding of its effect on human health worldwide.

Novel approach for detection of hepatitis E virus infection in German blood donors

The risk of transfusion-transmitted hepatitis E virus (HEV) infections by contaminated blood products remains unknown. In the present study, we evaluated and compared different nucleic acid amplification technique (NAT) methods for the detection of HEV in blood components. Minipools of a total of 16,125 individual blood donors were screened for the presence of HEV RNA using the highly sensitive RealStar HEV RT-PCR kit, revealing a minimum detection limit of 4.66 IU/ml. Thirteen donors were HEV RNA positive (0.08%), and of these donors, only three already showed reactive IgM antibody titers. The detected HEV strains all belonged to genotype 3 and were most closely related to German HEV strains from wild boars and pigs as well as from human hepatitis E cases. Furthermore, HEV RNA and HEV-specific IgM and IgG titers were determined in 136 blood donors with elevated alanine aminotransferase (ALT) levels and in 200 donors without pathological findings. HEV RNA was not detectable, but 8.08% (elevated ALT) and 0.5% (nonelevated ALT) of donors showed reactive HEV IgM titers. The overall seroprevalence rate of HEV IgG amounted to 5.94% (elevated ALT, 5.88%; nonelevated ALT, 6.0%). The clinical relevance of transfusion-associated hepatitis E infection still requires further investigation. However, in connection with raising concerns regarding blood safety, our NAT method provides a sensitive possibility for HEV testing.