Dosing ribavirin in hepatitis E-infected solid organ transplant recipients

Hepatitis E Virus (HEV) Infection Among Immunocompromised Individuals: A Brief Narrative Review

Hepatitis E virus (HEV) is a single-stranded positive-sense RNA virus that belongs to Hepeviridae family. HEV is the most common cause of acute viral hepatitis worldwide. According to the World Health Organization (WHO), there are estimated 20 million HEV infections worldwide every year, leading to estimated 3.3 million symptomatic cases of HEV infection. The WHO estimates that HEV infection caused approximately 44,000 deaths in 2015, which represents 3.3% of mortality rates due to viral hepatitis. In low-income (LI) countries and lower-middle-income (LMI) countries, HEV is a waterborne infection induced by HEV genotype (gt) 1 and HEV gt 2 that cause large outbreaks and affect young individuals with a high mortality rate in pregnant women from South Asian countries and patients with liver diseases. HEV gt 3, HEV gt 4, and HEV gt 7 are responsible for sporadic infections with zoonotic transmission mainly through the consumption of raw or undercooked meat from different animals. Acute HEV infection is relatively asymptomatic or mild clinical form, in rare cases the disease can be moderate/severe clinical forms and result in fulminant hepatitis or acute liver failure (ALF). Furthermore, HEV infection is associated with extrahepatic manifestations, including renal and neurological clinical signs and symptoms. Pregnant women, infants, older people, immunocompromised individuals, patients with comorbidities, and workers who come into close contact with HEV-infected animals are recognized as major risk groups for severe clinical form of HEV infection and fatal outcome. Chronic HEV infection can occur in immunocompromised individuals with the possibility of progression to cirrhosis.

Hepatitis E virus infection of transplanted kidneys

Immunocompromised patients are at risk of chronic hepatitis E (HEV) infection. Recurrent T cell and borderline rejections in a pediatric patient with high HEV copy numbers led us to study HEV infection within renal transplants. To investigate the frequency of renal HEV infection in transplanted patients, 15 samples from patients with contemporaneous diagnoses of HEV infection were identified at our center. Ten samples had sufficient residual paraffin tissue for immunofluorescence (IF) and RNA-fluorescence-in-situ-hybridization (RNA-FISH). The biopsy of the pediatric index patient was additionally sufficient for tissue polymerase chain reaction and electron microscopy. HEV RNA was detected in paraffin tissue of the index patient by tissue polymerase chain reaction. Subsequently, HEV infection was localized in tubular epithelial cells by IF, RNA-FISH, and electron microscopy. One additional biopsy from an adult was positive for HEV by RNA-FISH and IF. Focal IF positivity for HEV peptide was observed in 7 additional allografts. Ribavirin therapy was not successful in the pediatric index patient; after relapse, ribavirin is still administered. In the second patient, successful elimination of HEV was achieved after short-course ribavirin therapy. HEV infection is an important differential diagnosis for T cell rejection within transplanted kidneys. Immunostaining of HEV peptide does not necessarily prove acute infection. RNA-FISH seems to be a reliable method to localize HEV.

Chronic Hepatitis E Virus Manifesting as Elevated Transaminases in a Heart Transplant Patient

Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Genotypes 1 and 2 cause acute hepatitis in endemic regions (Asia and Africa), whereas genotypes 3 and 4 (America and Europe) result in sporadic acute or chronic hepatitis, specifically in certain groups. HEV infections are rising because of increased transplantation rates and immunosuppression. We report a 75-year-old heart transplant patient with nonspecific symptoms, diagnosed with HEV chronic hepatitis. Despite ribavirin-induced hemolytic anemia, the patient achieved sustained virological response and normalization of liver enzymes.

Ribonucleotide reductase as a therapeutic target for drug repurposing as anthelmintics

Visceral cestodiases, like echinococcoses and cysticercoses, are zoonoses of worldwide distribution and are responsible for public health problems in many countries, especially in underdeveloped regions. Current treatments have low efficiency and there are few drugs currently in use for chemotherapy, making the development of new anthelmintics an urgent matter. The nucleotide salvage pathways are the only ones available for nucleotide synthesis in cestodes and other parasitic helminths, and, here, we used in silico approaches to assess the potential of the enzymes in these pathways as targets for drug repurposing as anthelminthics. First, a genomic survey allowed to identify a repertoire of 28 enzymes of the purine and pyrimidine salvage pathways from the cestode Echinococcus granulosus sensu stricto. Regarding purines, the parasite relies on salvaging free bases rather than salvaging nucleosides. Pyrimidines, on the other hand, can be salvaged from both bases and nucleosides. Druggability of the parasite enzymes was assessed, as well as the availability of commercial inhibitors for them. Druggable enzymes were then ranked according to their potential for drug repurposing and the 17 most promising enzymes were selected for evolutionary analyses. The constructed phylogenetic trees allowed to assess the degree of conservation among ortholog enzymes from parasitic helminths and their mammalian hosts. Positive selection is absent in all assessed flatworm enzymes. A potential target enzyme for drug repurposing, ribonucleotide reductase (RNR), was selected for further assessment. RNR 3D-modelling showed structural similarities between the E. granulosus and the human orthologs suggesting that inhibitors of the human RNR should be effective against the E. granulosus enzyme. In line with that, E. granulosus protoscolices treated in vitro with the inhibitor hydroxyurea had their viability and DNA synthesis reduced. These results are consistent with nucleotide synthesis inhibition and confirm the potential of a nucleotide salvage inhibitors for repurposing as an anthelmintic.

Inhibition of tick-borne encephalitis virus in cell cultures by ribavirin

Tick-borne encephalitis virus (TBEV) belonging to arboviruses is a major member of zoonotic pathogens. TBEV infection causes severe human encephalitis without specific antiviral drugs. Due to its use of antiviral drug against a wide range of viruses, we investigated antiviral effect of ribavirin against TBEV in susceptible human cell lines A549 and SH-SY5Y. Ribavirin displayed minor cytotoxicity on multiple cell lines. Ribavirin obviously impaired TBEV replication and protected the infected cells from cytopathic effect. Importantly, ribavirin markedly inhibited TBEV propagation, as evidenced by impairment of TBEV production and viral RNA replication. Treatment with ribavirin (co-treatment and post-treatment) led to a dose-dependent reduction in TBEV titers as well as the viral RNA levels. Antiviral protein myxovirus resistance A mRNA expression was significantly up-regulated and signal transducer and activator of transcription 3 was activated in TBEV-infected A549 cells upon the ribavirin treatment. Induction of inflammatory cytokine tumor necrosis factor alpha by TBEV was decreased in A549 cells with the treatment of ribavirin, whereas interleukin 1 beta release appeared to be unaffected. These results suggest that ribavirin might represent a promising safe and effective antiviral drug against TBEV.

Hepatitis E Diagnosis and Management After Liver, Kidney, or Heart Transplant: A Single-Center Experience

BACKGROUND

Transplant-related hepatitis E virus (HEV) infection is a rarely recognized phenomenon with significant clinical importance given its potential to result in chronic hepatitis posttransplant.

METHODS

We retrospectively evaluated HEV diagnosis and treatment after liver, kidney, and heart transplant in a single center. We identified patients diagnosed with HEV by serologic testing and evaluated their treatment regimens.

RESULTS

Fifteen transplant recipients (12 liver, 2 kidney, and 1 heart) presented with elevated liver enzymes and were positive for HEV IgM antibody. Liver enzymes normalized in 4 patients after being treated with ribavirin. One of the 4 patients had 2 recurrences with positive HEV RNA results following ribavirin treatment but recovered after 12 months of ribavirin therapy. After treatment with reduction in immunosuppression without antiviral treatment, 6 of 8 patients' liver enzymes normalized. One of these patients died of acute pancreatitis 2 months after testing positive for HEV IgM antibody.

CONCLUSIONS

The potential for complications related to active HEV infections in transplant recipients necessitates prompt diagnosis and treatment to prevent irreversible damage. Diagnosis with HEV reverse transcriptase-polymerase chain reaction should follow a positive HEV IgM antibody test. This manuscript provides evidence that ribavirin antiviral therapy and reducing immunosuppression are effective treatments for HEV infections in liver, kidney, and heart transplant recipients, which has not been sufficiently investigated in the population of the United States. Larger multicenter studies are needed to confirm the risks and benefits of using ribavirin antiviral therapy as first-line therapy of HEV posttransplant.

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.

Low prevalence of anti-hepatitis E virus IgG antibodies in Tepehuanos in Mexico

INTRODUCTION AND OBJECTIVE

The epidemiology of infection with hepatitis E virus (HEV) in Tepehuanos (a Mexican ethnic group living in rural areas) is largely unknown. This study aimed to determine the seroprevalence of and risk factors associated with HEV infection in Tepehuanos in Durango, Mexico, and to compare this seroprevalence with that in non-Tepehuanos.

MATERIALS AND METHODS

Through a case-control seroprevalence study, we studied 146 Tepehuanos and 146 age- and gender-matched control subjects of the general population from rural settings. The frequency of anti-HEV IgG antibodies was determined using an enzyme-linked immunoassay. Bivariate and multivariate analyses were used to assess the association between seropositivity and socio-demographic, clinical and behavioral characteristics of the Tepehuanos.

RESULTS

IgG antibodies against HEV were found in 5 (3.4%; 95% CI: 1.1-7.8) of 146 Tepehuanos and in 46 (31.5%; 95% CI: 24.1-39.7) of 146 control subjects (OR=0.01; 95% CI: 0.0007-0.20; P<0.000001). Bivariate analysis showed that HEV seropositivity was associated with age, consumption of meat from goat, sheep, boar, turkey and pigeon, and concrete flooring at home. However, these variables were no longer significant when analyzed by logistic regression.

CONCLUSIONS

This is first study on the epidemiology of HEV exposure in Tepehuanos. We demonstrated serological evidence of HEV infection in this ethnic group. The seroprevalence of HEV exposure in Tepehuanos is low as compared with that found in non-Tepehuano people living in rural Durango. Further studies to determine the risk factors associated with HEV exposure in Tepehuanos are needed.

Determining the therapeutic range for ribavirin in transplant recipients with chronic hepatitis E virus infection

The aim of this study was to define the therapeutic range for ribavirin (RBV) in transplant recipients with chronic hepatitis E virus (HEV) infection. In this retrospective multicentre cohort study, data of adult transplant recipients with chronic HEV infection, who had been treated with RBV monotherapy between 01-3-2008 and 01-08-2018, were included. ROC curve analyses were performed, and the half-maximal effective RBV concentration was calculated to determine a representative therapeutic range. In 96 patients, RBV monotherapy for a median of three months resulted in a sustained virologic response in 63.5% of the patients, while 88.5% of the patients developed anaemia. RBV plasma concentrations at steady state were significantly higher in clinical responders compared with clinical non-responders: median 1.96 (IQR 1.81-2.70) versus 0.49 (IQR 0.45-0.73) mg/L, P = .0004. RBV caused a dose-dependent haemoglobin reduction with higher RBV plasma concentrations resulting in more haemoglobin reduction. The therapeutic range for RBV for chronic HEV infection in transplant recipients ranges between 1.8 and 2.3 mg/L.

Viral Hepatitis and Iron Dysregulation: Molecular Pathways and the Role of Lactoferrin

The liver is a frontline immune site specifically designed to check and detect potential pathogens from the bloodstream to maintain a general state of immune hyporesponsiveness. One of the main functions of the liver is the regulation of iron homeostasis. The liver detects changes in systemic iron requirements and can regulate its concentration. Pathological states lead to the dysregulation of iron homeostasis which, in turn, can promote infectious and inflammatory processes. In this context, hepatic viruses deviate hepatocytes' iron metabolism in order to better replicate. Indeed, some viruses are able to alter the expression of iron-related proteins or exploit host receptors to enter inside host cells. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein belonging to the innate immunity, is endowed with potent antiviral activity, mainly related to its ability to block viral entry into host cells by interacting with viral and/or cell surface receptors. Moreover, Lf can act as an iron scavenger by both direct iron-chelation or the modulation of the main iron-related proteins. In this review, the complex interplay between viral hepatitis, iron homeostasis, and inflammation as well as the role of Lf are outlined.

Inhibition of Hepatitis E Virus Spread by the Natural Compound Silvestrol

Every year, there are about 20 Mio hepatitis E virus (HEV) infections and 60,000 deaths that are associated with HEV worldwide. At the present, there exists no specific therapy for HEV. The natural compound silvestrol has a potent antiviral effect against the (-)-strand RNA-virus Ebola virus, and also against the (+)-strand RNA viruses Corona-, Picorna-, and Zika virus. The inhibitory effect on virus spread is due to an inhibition of the DEAD-box RNA helicase eIF4A, which is required to unwind structured 5'-untranslated regions (UTRs). This leads to an impaired translation of viral RNA. The HEV (+)-strand RNA genome contains a 5'-capped, short 5'-UTR. This study aims to analyze the impact of silvestrol on the HEV life cycle. Persistently infected A549 cells were instrumental. This study identifies silvestrol as a potent inhibitor of the release of HEV infectious viral particles. This goes along with a strongly reduced HEV capsid protein translation, retention of viral RNA inside the cytoplasm, and without major cytotoxic effects. Interestingly, in parallel silvestrol affects the activity of the antiviral major vault protein (MVP) by translocation from the cytoplasm to the perinuclear membrane. These data further characterize the complex antiviral activity of silvestrol and show silvestrol's broad spectrum of function, since HEV is a virus without complex secondary structures in its genome, but it is still affected.