Mortality and morbidity of locally acquired hepatitis E in the national Scottish cohort: a multicentre retrospective study

Hepatitis E as a trigger for acute-on-chronic liver failure

Acute hepatitis E virus (HEV) infection is typically self-limiting and has a favourable prognosis. However, certain populations such as patients with pre-existing chronic liver disease may experience severe manifestations, including progression to acute-on-chronic liver failure (ACLF). Among viral hepatitis types, hepatitis A, E, and B are major causes of ACLF. Active screening and early diagnosis of HEV infection in patients with cirrhosis, especially those who develop ACLF, can improve management and enable timely antiviral therapy. Preventive measures, including HEV vaccination for high-risk groups, could reduce the morbidity and mortality associated with hepatitis E.

Epidemiology and Outcomes of Hepatitis E Virus-Associated Hospitalisations in the United States With a Focus on Pregnancy: A Nationwide Population Study, 1998-2020

Hepatitis E virus (HEV) is typically asymptomatic in developed countries but can be more severe in certain populations. We aim to describe the epidemiology of HEV-associated hospitalisations from 1998 to 2020 in the United States, investigate risk factors for inpatient mortality and describe outcomes in pregnant women. We utilised the National Inpatient Sample and extracted cases of HEV-associated hospitalisations using ICD-9/10 diagnostic codes. Demographic, clinical and pregnancy data were extracted and analysed by chi-square and logistic regression. We identified 3354 cases of HEV-associated hospitalisations; 1689 (50.4%) were female and 1425 (42.5%) were non-Hispanic White. The median age was 50 (IQR: 37-59) years. Hospitalisation rates for HEV ranged from 2.5 per 10,000,000 in 2008 to a peak of 9.6 per 10,000,000 people in the general U.S. population in 2004. The mortality rate was 5.2%. Age ≥ 40 years (OR: 7.73; 95% CI: 1.57-38.09; p = 0.012), HIV infection (OR: 4.63; 95% CI: 1.26-16.97; p = 0.021), and coagulopathy (OR: 7.22; 95% CI: 2.81-18.57; p < 0.001) were associated with increased odds of mortality within the HEV cohort. There were 226 pregnant women with HEV. Rates of maternal death, stillbirth and preterm birth were similar between HEV and non-HEV pregnant cohorts. Hepatitis B and hepatitis C co-infection were significantly more common in the HEV pregnant cohort (p < 0.05). HEV-associated hospitalisations are uncommon in the United States, but likely underdiagnosed. Certain risk factors can be used to predict prognosis of these hospitalised patients. Pregnant women with HEV appear to have favourable maternal and fetal outcomes despite hepatitis B and C co-infection.

HEV ORF2 protein-antibody complex deposits are associated with glomerulonephritis in hepatitis E with reduced immune status

Hepatitis E virus (HEV) infection, one of the most common forms of hepatitis worldwide, is often associated with extrahepatic, particularly renal, manifestations. However, the underlying mechanisms are incompletely understood. Here, we report the development of a de novo immune complex-mediated glomerulonephritis (GN) in a kidney transplant recipient with chronic hepatitis E. Applying immunostaining, electron microscopy, and mass spectrometry after laser-capture microdissection, we show that GN develops in parallel with increasing glomerular deposition of a non-infectious, genome-free and non-glycosylated HEV open reading frame 2 (ORF2) capsid protein. No productive HEV infection of kidney cells is detected. Patients with acute hepatitis E display similar but less pronounced deposits. Our results establish a link between the production of HEV ORF2 protein and the development of hepatitis E-associated GN in the immunocompromised state. The formation of glomerular IgG-HEV ORF2 immune complexes discovered here provides a potential mechanistic explanation of how the hepatotropic HEV can cause variable renal manifestations. These findings directly provide a tool for etiology-based diagnosis of hepatitis E-associated GN as a distinct entity and suggest therapeutic implications.

Inborn errors of type I interferon immunity in patients with symptomatic acute hepatitis E

BACKGROUND AND AIMS

The clinical spectrum of human infection by HEV ranges from asymptomatic to severe acute hepatitis. Furthermore, HEV can cause diverse neurological manifestations, especially Parsonage-Turner syndrome. Here, we used a large-scale human genomic approach to search for genetic determinants of severe clinical presentations of HEV infection.

APPROACH AND RESULTS

We performed whole genome sequencing in 3 groups of study participants with PCR-proven acute HEV infection: (1) 24 patients with symptomatic acute hepatitis E; (2) 12 patients with HEV-associated Parsonage-Turner syndrome; and (3) 16 asymptomatic blood donors (controls). For variant calling and annotation, we used GATK4 best practices followed by Variant Effect Predictor (VEP) and Annovar. For variant classification, we implemented the American College of Medical Genetics and Genomics/Association for Molecular Pathology Bayesian classification framework in R. Variants with a probability of pathogenicity >0.9 were considered damaging. We used all genes with at least 1 damaging variant as input for pathway enrichment analyses.We observed a significant enrichment of type I interferon response pathways in the symptomatic hepatitis group: 10 out of 24 patients carried a damaging variant in one of 9 genes encoding either intracellular viral sensors ( IFIH1 , DDX58 , TLR3 , POLR3B , POLR3C ) or other molecules involved in type I interferon response [interferon regulatory factor 7 ( IRF7 ), MYD88 , OAS3 , GAPDH ]. We did not find any enriched pathway in the Parsonage-Turner syndrome group or in the controls.

CONCLUSIONS

Our results highlight the essential role of type I interferon in preventing symptomatic acute hepatitis E.

Viral hepatitis E: Clinical manifestations, treatment, and prevention

Hepatitis E is a globally distributed infection that varies in seroprevalence between developed and developing regions. In the less developed regions of Asia and Africa, a high seropositivity rate has been reported for hepatitis E virus (HEV) antibodies. Although acute hepatitis E is often self-limited and has a favorable prognosis, some populations experience severe manifestations, which may progress to liver failure. Moreover, some immunocompromised patients are at risk of developing chronic HEV infection and cirrhosis. Proactive screening, reducing misdiagnosis, improving patient management, timely antiviral therapy for severe and chronic cases, and vaccination of high-risk groups are important measures to reduce the morbidity of hepatitis E. This review focused on the clinical presentation, management, and prevention of hepatitis E.

Viral Biology and Immune Privilege in the Development of Extrahepatic Manifestations During Hepatitis E Virus Infection

Hepatitis E virus (HEV) exhibits tropism toward hepatocytes and thus affects the liver; however, HEV may also affect other tissues, including the heart, kidneys, intestines, testicles, and central nervous system. To date, the pathophysiological links between HEV infection and extrahepatic manifestations have not yet been established. Considering that HEV infects multiple types of cells, the direct effects of virus replication in peripheral tissues represent a plausible explanation for extrahepatic manifestations. In addition, since the immune response is crucial in the development of the disease, the immune characteristics of affected tissues should be revisited to identify commonalities explaining the effects of the virus. This review summarizes the most recent advances in understanding the virus biology and immune-privileged status of specific tissues as major elements for HEV replication in diverse organs. These discoveries may open avenues to explain the multiple extrahepatic manifestations associated with HEV infection and ultimately to design effective strategies for infection control.

Clinical characteristics of 1279 patients with hepatitis E in Tianjin

Hepatitis E virus infection is a major cause of acute hepatitis, typically self-limiting but occasionally leading to liver failure. Understanding disease progression factors could inform prevention strategies. This study aimed to analyse the characteristics of a large cohort of hospitalised hepatitis E patients in Tianjin, China, and explore factors influencing their progression to liver failure. A total of 1279 hospitalised patients with hepatitis E were included in this cross-sectional study in Tianjin, China. Student's t-test and the Mann-Whitney U-test were used for comparisons. Multiple logistic regression analysis was used to explore the association. Among these 1279 patients, 107 (8.4%) developed liver failure. Patients with diabetes mellitus (DM) (95% confidence interval [CI] 1.150-2.887, p = 0.011), liver cirrhosis (95% [CI] 2.229-7.224, p < 0.001), and hepatitis B (95% [CI] 1.159-4.512, p = 0.017) were more likely to progress to liver failure. Hepatitis E patients with comorbid DM, liver cirrhosis, or hepatitis B virus co-infection have higher risks of developing liver failure. Hepatitis E vaccination may be recommended for these vulnerable patients to curb disease severity.

Risk Factors for Hepatitis E Virus Infection and Eating Habits in Kidney Transplant Recipients

There is a significant risk for ongoing and treatment-resistant courses of hepatitis E virus (HEV) infection in patients after solid organ transplantation. The aim of this study was to identify risk factors for the development of hepatitis E, including the dietary habits of patients. We conducted a retrospective single-center study with 59 adult kidney and combined kidney transplant recipients who were diagnosed with HEV infection between 2013 and 2020. The outcomes of HEV infections were analyzed during a median follow-up of 4.3 years. Patients were compared with a control cohort of 251 transplant patients with elevated liver enzymes but without evidence of an HEV infection. Patients' alimentary exposures during the time before disease onset or diagnosis were assessed. Previous intense immunosuppression, especially treatment with high-dose steroids and rituximab, was a significant risk factor to acquire hepatitis E after solid organ transplantation. Only 11 out of 59 (18.6%) patients reached remission without further ribavirin (RBV) treatment. A total of 48 patients were treated with RBV, of which 19 patients (39.6%) had either viral rebounds after the end of treatment or did not reach viral clearance at all. Higher age (>60 years) and a BMI ≤ 20 kg/m² were risk factors for RBV treatment failure. Deterioration in kidney function with a drop in eGFR (p = 0.046) and a rise in proteinuria was more common in patients with persistent hepatitis E viremia. HEV infection was associated with the consumption of undercooked pork or pork products prior to infection. Patients also reported processing raw meat with bare hands at home more frequently than the controls. Overall, we showed that the intensity of immunosuppression, higher age, a low BMI and the consumption of undercooked pork meat correlated with the development of hepatitis E.

A frantic confusion: beyond rabies and anti-N-methyl-D-aspartate encephalitis

Hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. In rare cases, HEV may generate neurologic lesions such as neuralgic amyotrophy, Guillain-Barré syndrome, and meningoencephalitis. Thirteen cases of HEV meningoencephalitis have been reported over 20 years. The clinical landscape varied from mild symptoms to coma and seizures. Most of patients were immunocompetent adults and spontaneously recovered. We report here the case of a 44-year-old immunocompetent adult with HEV meningoencephalitis presenting with aggressiveness and then coma. The evolution was spontaneously favorable without any specific treatment. This clinical case aims to draw attention on this emerging and probably under-recognized cause of meningoencephalitis.

Prognosis of hepatitis E infection in patients with chronic liver disease: A meta-analysis

In individuals with underlying chronic liver disease (CLD), hepatitis E virus (HEV) infection is a potential trigger of acute-on-chronic liver failure. In this systematic review, seven electronic databases were searched. Pooled incidence rates with 95% confidence intervals (95% CIs) were calculated by the Freeman-Tukey double arcsine transformation method. The association between death or liver failure and HEV superinfection in CLD patients was estimated by the odds ratios (OR) with a 95% CI. A total of 18 studies from 5 countries were eligible for systematic review. The prevalence of acute HEV infection in hospitalized CLD patients with clinical manifestations of hepatitis was 13.6%, which was significantly higher than that in CLD patients from the community (pooled prevalence 1.1%). The overall rates of liver failure and mortality in CLD patients with HEV superinfection were 35.8% (95% CI: 26.7%-45.6%) and 14.3% (95% CI: 10.6%-18.5%), respectively, with the rates in cirrhotic patients being approximately 2-fold and 4-fold higher than those in noncirrhotic patients, respectively. The risks of liver failure (OR = 5.5, 95% CI: 1.5-20.1) and mortality (OR = 5.0, 95% CI: 1.9-13.3) were significantly higher in CLD patients with HEV superinfection than in those without HEV superinfection. HEV testing in hospitalized CLD patients is necessary due to the high prevalence of HEV infection observed in hospitalized CLD patients. HEV superinfection could accelerate disease progression in patients with underlying CLD and increase mortality in these patients. HEV vaccination is appropriate for patients with pre-existing CLD.

Puzzles for Hepatitis E Virus

Hepatitis E virus (HEV) is an important but understudied virus that has been the major cause of acute viral hepatitis worldwide. In recent decades, our understanding of this neglected virus has changed greatly: novel forms of viral proteins and their functions have been discovered; HEV can transmit via blood transfusion and organ transplantation; HEV can infect many animal species and the number is still increasing; HEV can induce chronic hepatitis and extra-hepatic manifestations. However, we are short of effective treatment measures to counter the virus. In this chapter we tend to briefly introduce the puzzles and major knowledge gaps existed in the field of HEV research.

Viral clade is associated with severity of symptomatic genotype 3 hepatitis E virus infections in Belgium, 2010-2018

BACKGROUND & AIMS

HEV genotype (gt) 3 infections are prevalent in high-income countries and display a wide spectrum of clinical presentations. Host - but not viral - factors are reported to be associated with worse clinical outcomes.

METHODS

Demographic, clinical, and biochemical data laboratory-confirmed HEV infections (by PCR and/or a combination of IgM and IgG serology) at the Belgian National Reference Centre between January 2010 and June 2018 were collected using standardised case report forms. Genotyping was based on HEV open reading frame 2 sequences. Serum CXCL10 levels were measured by a magnetic bead-based assay. H&E staining was performed on liver biopsies.

RESULTS

A total of 274 HEV-infected individuals were included. Subtype assignment was possible for 179/218 viraemic cases, confirming gt3 as dominant with an almost equal representation of clades abchijklm and efg. An increased hospitalisation rate and higher peak serum levels of alanine aminotransferase, bilirubin, and alkaline phosphatase were found in clade efg-infected individuals in univariate analyses. In multivariable analyses, clade efg infections remained more strongly associated with severe disease presentation than any of the previously identified host risk factors, being associated with a 2.1-fold higher risk of hospitalisation (95% CI 1.1-4.4, p = 0.034) and a 68.2% higher peak of bilirubin levels (95% CI 13.3-149.9, p = 0.010), independently of other factors included in the model. In addition, acute clade efg infections were characterised by higher serum CXCL10 levels (p = 0.0005) and a more pronounced liver necro-inflammatory activity (p = 0.022).

CONCLUSIONS

In symptomatic HEV gt3 infections, clade efg is associated with a more severe disease presentation, higher serum CXCL10 levels, and liver necro-inflammatory activity, irrespective of known host risk factors.

CLINICAL TRIAL REGISTRATION

The protocol was submitted to clinicaltrials.gov (NCT04670419).

IMPACT AND IMPLICATIONS

HEV genotype (gt) 3 infections display a wide spectrum of clinical presentations currently ascribed to host factors. Here we examined the role of viral factors on liver disease outcomes by combining viral phylogeny with clinical, biochemical, cytokine, and histological data from 274 Belgian adults infected with HEV presenting between 2010 and 2018. HEV gt 3 clade efg infections were associated with a more severe disease presentation, higher serum CXCL10 levels and liver necro-inflammatory activity, irrespective of known host risk factors. HEV gt3 clade-dependent clinical outcomes call for broad HEV gt3 subtyping in clinical practice and research to help identify those at higher risk for worse outcomes and to further unravel underlying virus-host interactions.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Incidence of Hepatitis E Infection in American Patients With Suspected Drug-Induced Liver Injury Is Low and Declining: The DILIN Prospective Study

INTRODUCTION

Hepatitis E virus (HEV) infection rarely causes icteric hepatitis, yet 10%-40% of adult Americans have serological evidence of previous infection. The aim of this study was to investigate the incidence, presentation, and outcome of acute and previous HEV infection in a large cohort of patients with suspected drug-induced liver injury (DILI).

METHODS

Serum samples from 2012 patients enrolled in the DILI Network were tested for anti-HEV immunoglobulin G (IgG). Those with detectable anti-HEV IgG underwent testing for anti-HEV IgM; those with detectable anti-HEV immunoglobulin m (IgM) were tested for HEV RNA.

RESULTS

Anti-HEV IgG was detected in 407 (20%) patients and associated with increasing subject age and earlier year of enrollment. The median age of seropositive subjects was more than a decade higher than seronegative subjects (59.8 vs 48.7 years). The overall prevalence of anti-HEV declined from 22% (2004-2011) to 18% (2012-2019), suggestive of a cohort effect. The frequency of acute hepatitis E (median ALT = 1231 IU/L) also decreased from 3% (2004-2008) to 1.2% (2009-2013) to 0.6% (2014-2019). These results suggest that acute HEV infection is usually subclinical and was much more frequent in this cohort before 2004.

DISCUSSION

Acute HEV infection accounts for less than 1% of suspected American DILI cases and is more frequent in older men. Previous HEV infection is also most commonly seen in older individuals. Clinicians should consider testing for unsuspected acute HEV infection in older adult patients with acute hepatocellular DILI and jaundice.

Hepatitis E Virus; An Underestimated Threat for the Viral Hepatitis Elimination Program

Collapse

Review of clinical characteristics, immune responses and regulatory mechanisms of hepatitis E-associated liver failure

Hepatitis E virus (HEV) is the most common cause of acute liver failure (LF) and one of the most common factors causing acute injury in acute-on-chronic LF (ACLF). When HEV-related LF occurs, a series of changes take place in both the intrahepatic environment and extrahepatic microenvironment. The changed types and distribution of immune cells (infiltrating macrophages and increased lymphocytes) in liver tissue, as well the increased proinflammatory cytokines and chemokines in the blood, indicate that the occurrence and progression of HEV-related LF are closely related to immune imbalance. The clinical features and immune reaction in the body during HEV-related acute LF (ALF) and ACLF are complicated. This review highlights recent progress in elucidating the clinical manifestations of HEV-associated ALF and ACLF and discusses the corresponding systemic immune changes and possible regulatory mechanisms.

Transfusion-transmitted hepatitis E: What we know so far?

Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. There is growing concern about transfusion-transmitted HEV (TT-HEV) as an emerging global health problem. HEV can potentially result in chronic infection in immunocompromised patients, leading to a higher risk of liver cirrhosis and even death. Between 0.0013% and 0.281% of asymptomatic blood donors around the world have HEV viremia, and 0.27% to 60.5% have anti-HEV immunoglobulin G. HEV is infectious even at very low blood concentrations of the virus. Immunosuppressed patients who develop persistent hepatitis E infection should have their immunosuppressant regimen reduced; ribavirin may be considered as treatment. Pegylated interferon can be considered in those who are refractory or intolerant to ribavirin. Sofosbuvir, a nucleotide analog, showed modest antiviral activity in some clinical studies but sustained viral response was not achieved. Therefore, rescue treatment remains an unmet need. The need for HEV screening of all blood donations remains controversial. Universal screening has been adopted in some countries after consideration of risk and resource availability. Various pathogen reduction methods have also been proposed to reduce the risk of TT-HEV. Future studies are needed to define the incidence of transmission through transfusion, their clinical features, outcomes and prognosis.

Hepatitis E Virus Infection: Neurological Manifestations and Pathophysiology

Hepatitis E virus (HEV) is the first cause of viral hepatitis in the world. While the water-borne HEV genotypes 1 and 2 are found in developing countries, HEV genotypes 3 and 4 are endemic in developed countries due to the existence of animal reservoirs, especially swine. An HEV infection produces many extra-hepatic manifestations in addition to liver symptoms, especially neurological disorders. The most common are neuralgic amyotrophy or Parsonage–Turner syndrome, Guillain–Barré syndrome, myelitis, and encephalitis. The pathophysiology of the neurological injuries due to HEV remains uncertain. The immune response to the virus probably plays a role, but direct virus neurotropism could also contribute to the pathophysiology. This review describes the main neurological manifestations and their possible pathogenic mechanisms.

Hepatitis E virus infection increases the risk of diabetes and severity of liver disease in patients with chronic hepatitis C virus infection

OBJECTIVES

Co-infection with hepatitis A or B viruses may aggravate liver injury in patients infected with hepatitis C virus (HCV). However, few studies have assessed co-infection with hepatitis E virus (HEV) and HCV. Therefore, this study aimed to assess the prevalence and impact of HEV infection among Brazilian patients with chronic HCV infection.

METHODS

This observational study included adult patients with chronic HCV infection who were naive to antiviral therapy from January 2013 to March 2016. A total of 181 patients were enrolled, and HEV serology and PCR were performed for all patients.

RESULTS

Seropositivity for anti-HEV IgG was detected in 22 (12.0%) patients and anti-HEV immunoglobulin M in 3 (1.6%). HEV RNA showed inconclusive results in nine (4.9%) patients and was undetectable in the remaining patients. HEV serology positive patients had more severe liver disease, characterized by liver fibrosis ≥3 versus ≤2 (p<0.001), Aspartate Aminotransferase-to-Platelet Ratio Index of ≥1.45 (p=0.003), and Fibrosis-4 score of ≥3.25 (p=0.001). Additionally, the odds of HEV-positive patients developing diabetes mellitus were 3.65 (95% CI 1.40-9.52) times the corresponding odds of HEV-negative patients. A case-control-based histological analysis (n=11 HEV-HCV-positive patients and n=22 HCV-positive patients) showed no significant differences between the groups.

CONCLUSIONS

This prevalence is higher than that reported in previous studies of the general population in Brazil. Thus, HEV infection may influence the severity of liver disease and may represent an additional risk of developing diabetes mellitus in patients with HCV infection.

Comparison of detection strategies for screening and confirming congenital cytomegalovirus infection in newborns in a highly seroprevalent population: a mother-child cohort study

Background

Universal screening of congenital cytomegalovirus (cCMV) infection is important for monitoring and intervention during critical stages of speech and language development. This study aimed to explore the optimal detection strategy for cCMV infection screening.

Methods

Serum samples from pregnant women and saliva and urine samples from their newborns were collected for the anti-CMV IgG and CMV DNA PCR tests, respectively. The sensitivity, specificity, and predictive values as well as the likelihood ratios of 12 potential screening strategies for cCMV infection, based on tests for saliva, urine, and their combination, were evaluated.

Findings

A total of 6729 pregnant women were enrolled, and the seroprevalence was 98.1%. Among 6350 newborns that were followed up, 49 were defined as having cCMV infection. In the screening test, the CMV DNA positivity rate remained similar from day 0 to day 5, increased slowly from day 6 to day 13, and became high in newborns beyond 13 days of birth. In the confirmatory testing, the positive rates increased significantly beyond day 21. For the 49 newborns with cCMV infection, the proportion of agreement between saliva and urine testing was poor. Upon evaluating alternative screening strategies, using saliva and urine screening with saliva and urine confirmation as the reference strategy, saliva screening with saliva and urine confirmation showed good diagnostic accuracy and feasibility, with sensitivity, specificity, positive predictive and negative predictive values of 85.7%, 100.0%, 100.0% and 99.9%, respectively.

Interpretation

In populations with high seroprevalence, saliva screening with saliva and urine confirmation might be an alternative strategy for screening cCMV infections. The suggested timeframes for screening and confirmation are within 13 (ideally 5) and 21 (ideally 13) days of birth, respectively.

Funding

National Natural Science Foundation of China, National Science and Technology Major Project of China and Merck & Co., Inc., Kenilworth, New Jersey, U.S.A.

Extrahepatic manifestations related to hepatitis E virus infection and their triggering mechanisms

Hepatitis E virus (HEV) infection has many extrahepatic manifestations as well as liver symptoms. Multiple studies have shown that HEV infection has symptoms related to the nervous system, kidneys, cryoglobulinemia, hematological system, reproductive system, autoimmunity and pancreas. Hence, HEV infection should be considered as a systemic disease, rather than solely a liver disease. The extrahepatic manifestations induced by different genotypes of HEV vary. The severity of these diseases does not necessarily correlate with the severity of HEV infection, and even asymptomatic HEV infection may trigger and cause systemic diseases. Patients with systemic manifestations of HEV infection should have priority for antiviral therapy, which could alleviate or improve the extrahepatic manifestations related to HEV infection. However, the extrahepatic manifestations caused by different genotypes of HEV and their corresponding mechanisms have not been clearly identified. This review discusses the extrahepatic manifestations related to HEV infection and their triggering mechanisms.

Control of Raw Pork Liver Sausage Production Can Reduce the Prevalence of HEV Infection

After an acute hepatitis E (HEV) outbreak in Southern Switzerland, in January 2017 the local public health authorities started an active program of food chain control and public education. In this retrospective study, we analysed all laboratory-confirmed acute cases of HEV infection diagnosed between 2014 and 2020. In the period before the public health intervention, the number of cases increased steadily from 2014 (4 of 40 tests, 10%) reaching a peak in the last quarter of 2016 (42 of 285 tests, 14.7 %). Afterwards, the number of positive cases decreased steadily, reaching its lowest value (0.3%) in the second quarter of 2019. There was a statistically significant difference between the frequency of positive cases and period of testing, i.e., before and after the introduction of the public health interventions. Our study shows that active public health measures to control sausages containing raw pork liver can reduce the prevalence of HEV infection.

Th1/Th2 Cells and Associated Cytokines in Acute Hepatitis E and Related Acute Liver Failure

Background and Aims

The involvement of cellular immunity in the development of hepatitis E virus (HEV) infection is rare. We aimed to study the roles of viral load and Th cell responses in acute hepatitis E (AHE) and HEV-related acute liver failure (HEV-ALF).

Methods

We evaluated viral load and Th1/Th2 cytokine levels in 34 patients with HEV infection, including 17 each with AHE or HEV-ALF. Seventeen healthy controls (HCs) were also included who were negative for anti-HEV IgM and IgG.

Results

There was no significant difference in viral load and HEV RNA in the AHE and HEV-ALF groups (both P > 0.05). The Th lymphocyte levels (CD3+, CD4+) in the AHE and HEV-ALF groups were significantly higher than those in the HC group (both P < 0.05), but there was no significant difference between the AHE and HEV-ALF groups (P > 0.05). Both IFN-γ and IL-10 showed gradual upward trend from the HC group to the AHE (both P < 0.01), but IFN-γ showed a sharp downward trend from the AHE group to the HEV-ALF group (P < 0.01) and IL-4 showed gradual upward trend from the AHE group to the HEV-ALF group (P < 0.01).There was no significant difference in Th1 and Th2 cytokines between the HEV RNA(+) group and HEV RNA(-) group (all P > 0.05). Th2 bias was observed from the AHE (ratio = 58.65) to HEV-ALF (ratio = 1.20) groups. The level of IFN-γ was associated with the outcome of HEV-ALF patients.

Conclusions

HEV viral load was not associated with aggravation of AHE, and the HEV-ALF patients showed significant Th2 bias, which may be involved in the aggravation of AHE.

Role of Hepatitis E Virus Infection in North American Patients With Severe Acute Liver Injury

INTRODUCTION

The aim of this study was to determine the role of hepatitis E virus (HEV) infection in a large cohort of prospectively enrolled patients with severe acute liver injury (ALI).

METHODS

Serum samples from 594 consecutive adults enrolled between 2008 and 2018 in the US Acute Liver Failure Study Group ALI registry were tested for anti-HEV IgM and anti-HEV IgG levels. Those with detectable anti-HEV IgM underwent further testing for HEV RNA using real-time polymerase chain reaction.

RESULTS

The median age of patients was 38 years; 41% were men and 72% Caucasian. Etiologies of ALI included acetaminophen hepatotoxicity (50%), autoimmune hepatitis (8.9%), hepatitis B virus (8.9%), and idiosyncratic drug-induced liver injury (7.9%). Overall, 62 patients (10.4%) were negative for anti-HEV IgM but positive for IgG, whereas only 3 men (0.5%) were positive for both anti-HEV IgM and IgG. These 3 cases were initially diagnosed as having indeterminate, HEV, and hepatitis B virus-related ALI. One of these patients had detectable HEV RNA genotype 3, and another anti-HEV IgM+ patient had detectable HEV antigens by immunohistochemistry on liver biopsy. On multivariate modeling, older (odds ratio: 1.99) and non-Caucasian subjects (odds ratio: 2.92) were significantly more likely to have detectable anti-HEV IgG (P < 0.0001).

DISCUSSION

Acute HEV infection is an infrequent cause of ALI in hospitalized North American adults. The anti-HEV IgG+ patients were significantly older and more likely to be non-Caucasian. These data are consistent with other population-based studies that indicate exposure to HEV in the general US population is declining over time and might reflect a cohort effect.