Comprehensive Evaluation of Hepatitis E Serology and Molecular Testing in a Large Cohort

Clinical utility of two-step hepatitis E virus IgM antibody testing in a low-prevalence setting: A 10-year retrospective multicenter study

BACKGROUND

Diagnostic uncertainty caused by the low positive predictive value of HEV-specific IgM antibody (Ab) testing in a low-prevalence setting. We investigated the utility of a two-step HEV IgM Ab testing approach for diagnosing HEV infection.

METHODS

We retrospectively reviewed all adults who underwent HEV IgM Ab and/or HEV RNA testing from July 2013 through June 2023 at Mayo Clinic. Two-step HEV IgM testing involved initial testing using recomWell HEV IgM ELISA (Mikrogen, Neuried, Germany), with reflex to recomLine HEV IgM Strip (Mikrogen, Neuried, Germany) on all recomWell HEV IgM-reactive or IgM-equivocal specimens, as recomLine HEV IgM has higher specificity than recomWell HEV IgM but is more labor-intensive.

RESULTS

A total of 1640 patients had HEV IgM Ab or HEV RNA testing, including 1293 (79%) with only HEV IgM Ab testing, 213 (13%) with only HEV RNA testing, and 134 (8%) with both HEV IgM Ab and HEV RNA testing. Eighteen HEV infections were diagnosed with acute (N=16) and chronic (N=2) infections. Two-step IgM Ab testing did not identify 2 solid organ transplant recipients with chronic HEV infection. In acute HEV infection with HEV viremia, 3 out of 4 patients (2 solid organ transplant recipients and 1 patient with Guillain-Barre syndrome) were treated with ribavirin.

CONCLUSIONS

A two-step HEV IgM Ab test may accurately diagnose acute HEV infection in immunocompetent persons. However, this approach fails to identify chronic HEV infection in immunocompromised individuals who need HEV RNA testing to establish the diagnosis.

Diagnostic accuracy of hepatitis E virus antibody tests: A comprehensive meta-analysis

AIM

Hepatitis E virus (HEV) is a major global health issue, with an estimated 20 million infections annually. Although polymerase chain reaction (PCR) is the diagnostic gold standard due to its precision, it is expensive and technically demanding. Antibody tests offer a more practical and cost-effective alternative, although their accuracy can vary due to factors, such as test manufacturer, antigen composition, HEV genotype, and host immune status.

METHODS

A comprehensive search was conducted in PubMed, Cochrane, Scopus, and Web of Science databases. Studies included comparing the sensitivity and specificity of immunoglobulin M or immunoglobulin G antibody tests to PCR. Exclusion criteria were non-PCR comparisons, sample sizes under 10, IgA or antigen tests, non-human samples, or missing sensitivity and specificity data. Only English-language full-texts or abstracts were considered. Data analysis was performed using Meta-DTA v2.1.1 and Stata 16.0.

RESULTS

The meta-analysis evaluated 8054 blood samples from 21 studies. Immunoglobulin M antibody tests demonstrated an overall sensitivity of 83% (95% CI 76-88) and specificity of 98% (95% CI 97-99). Immunoglobulin G tests showed a sensitivity of 74% (95% CI 62-82) and specificity of 89% (95% CI 84-93). Among manufacturers, Wantai was the most accurate for immunoglobulin M detection, whereas MP led for immunoglobulin G. Notably, test sensitivity improved when the test protein genotype aligned with the HEV genotype.

CONCLUSION

This meta-analysis confirmed that antibody assays have a good sensitivity and high specificity to detect HEV infection in situations where PCR is not feasible, highlighting their potential as a practical diagnostic tool.

Hepatitis E Virus Infection Epidemiology in Recipients of Allogeneic Hematopoietic Cell Transplant

Among 292 recipients of allogeneic hematopoietic cell transplant (2018-2022), 64 (21.9%) tested positive for anti-hepatitis E virus (HEV) immunoglobulin G. Among 208 recipients tested by plasma/serum HEV polymerase chain reaction (2012-2022), 3 (1.4%) primary HEV infections were diagnosed; in 1 patient, plasma HEV polymerase chain reaction relapsed positive for 100 days. HEV infection remains rare albeit associated with persistent viral replication.

An immunoassay system to investigate epidemiology of Rocahepevirus ratti (rat hepatitis E virus) infection in humans

Background & Aims

Rat hepatitis E virus (Rocahepevirus ratti; HEV-C1) is an emerging cause of hepatitis E that is divergent from conventional human-infecting HEV variants (Paslahepevirus balayani; HEV-A). Validated serological assays for HEV-C1 are lacking. We aimed to develop a parallel enzymatic immunoassay (EIA) system that identifies individuals with HEV-C1 exposure. We also aimed to conduct the first HEV-C1 seroprevalence study in humans using this validated EIA system.

Methods

Expressed HEV-A (HEV-A4 p239) and HEV-C1 (HEV-C1 p241) peptides were characterised. Blood samples were simultaneously tested in HEV-A4 p239 and HEV-C1 p241 IgG EIAs. An optical density (OD) cut-off-based interpretation algorithm for identifying samples seropositive for HEV-A or HEV-C1 was validated using RT-PCR-positive infection sera. This algorithm was used to measure HEV-C1 seroprevalence in 599 solid organ transplant recipients and 599 age-matched immunocompetent individuals.

Results

Both peptides formed virus-like particles. When run in HEV-A4 p239 and HEV-C1 p241 EIAs, HEV-A and HEV-C1 RT-PCR-positive samples formed distinct clusters with minimal overlap in a two-dimensional plot of optical density values. The final EIA interpretation algorithm showed high agreement with RT-PCR results (Cohen's κ = 0.959) and was able to differentiate HEV-A and HEV-C1 infection sera with an accuracy of 94.2% (95% CI: 85.8-98.4%). HEV-C1 IgG seroprevalence was 7/599 (1.2%) among solid organ transplant recipients and 4/599 (0.7%) among immunocompetent individuals. Five of 11 (45.5%) of these patients had history of transient hepatitis of unknown cause.

Conclusions

HEV-C1 exposure was identified in 11/1198 (0.92%) individuals in Hong Kong indicating endemic exposure. This is the first estimate of HEV-C1 seroprevalence in humans. The parallel IgG EIA algorithm is a valuable tool for investigating epidemiology and risk factors for HEV-C1 infection.

Impact and Implications

Rat hepatitis E virus has recently been discovered to infect humans, but antibody tests for this infection are lacking, making it difficult to gauge how common this infection is. We developed an antibody test algorithm that can identify individuals with past rat hepatitis E virus exposure. We used this algorithm to estimate rat hepatitis E exposure rates in humans in Hong Kong and found that approximately 1% of all tested people had been exposed to this virus previously.

Distinct disease features of acute and persistent genotype 3 hepatitis E virus infection in immunocompetent and immunosuppressed Mongolian gerbils

Hepatitis E virus (HEV) causes self-limited acute hepatitis in immunocompetent individuals and can establish chronic infection in solid organ transplant recipients taking immunosuppressive drugs. A well characterized small animal model is needed to understand HEV pathogenesis. In this study, we established a robust model to study acute and persistent HEV infection using Mongolian gerbils (Meriones unguiculatus) with or without immunosuppression. Gerbils were implanted subcutaneously with continuous release tacrolimus pellet to induce immunosuppression. Gerbils with or without tacrolimus treatment were inoculated with HEV intraperitoneally. Viremia, fecal virus shedding, serum antibody and ALT levels, liver histopathological lesions, hepatocyte apoptosis, and liver macrophage distribution were assessed. Mild to moderate self-limited hepatitis and IgM and IgG antibody responses against HEV ORF2 were observed in immunocompetent gerbils. Levels of HEV-specific IgM responses were higher and lasted longer in immunocompetent gerbils with higher peak viremia. Persistent viremia and fecal virus shedding with either weak, or absent HEV antibody levels were seen in immunosuppressed gerbils. Following HEV infection, serum ALT levels were increased, with lower and delayed peaks observed in immunosuppressed compared to immunocompetent gerbils. In immunocompetent gerbils, foci of apoptotic hepatocytes were detected that were distributed with inflammatory infiltrates containing CD68+ macrophages. However, these foci were absent in immunosuppressed gerbils. The immunosuppressed gerbils showed no inflammation with no increase in CD68+ macrophages despite high virus replication in liver. Our findings suggest adaptive immune responses are necessary for inducing hepatocyte apoptosis, CD68+ macrophage recruitment, and inflammatory cell infiltration in response to HEV infection. Our studies show that Mongolian gerbils provide a promising model to study pathogenesis during acute and persistent HEV infection.

Development and clinical validation of a one-step pentaplex real-time reverse transcription PCR assay for detection of hepatitis virus B, C, E, Treponema pallidum, and a human housekeeping gene

BACKGROUND

With the safety of blood transfusion being a major public health concern, the development of a rapid, sensitive, specific, and cost-effective multiplex PCR assay for simultaneous detection of hepatitis B virus(HBV), hepatitis C virus (HCV), hepatitis E virus (HEV), and Treponema pallidum(T. pallidum) in blood is crucial.

METHODS

Five primer pairs and probes were designed towards conserved regions of target genes and used to establish a one-step pentaplex real-time reverse transcription PCR(qRT-PCR) assay for simultaneous detection of HBV, HCV, HEV, T. pallidum, and RNase P(housekeeping gene), providing sample quality check. The clinical performance of the assay was further determined with 2400 blood samples from blood donors and patients in Zhejiang province, and compared the results with commercial singleplex qPCR and serological assays.

RESULTS

The 95% limit of detection(LOD) of HBV, HCV, HEV, and T. pallidum were 7.11 copies/µL, 7.65 copies/µL, 8.45 copies/µL, and 9.06 copies/µL, respectively. Moreover, the assay has good specificity and precision. Compared to the singleplex qPCR assay, the novel assay for detecting HBV, HCV, HEV, and T. pallidum presented 100% clinical sensitivity, specificity, and consistency. Several discrepant results between serological and pentaplex qRT-PCR assays were found. Of 2400 blood samples, there were 2(0.08%) HBsAg positive samples, 3(0.13%) anti-HCV positive samples, 29(1.21%) IgM anti-HEV positive samples and 6(0.25%) anti-T. pallidum positive samples proven negative in nucleic acid detection. 1(0.04%) HBV DNA positive sample and 1(0.04%) HEV RNA positive sample were detected negative by serological testing.

CONCLUSIONS

The developed pentaplex qRT-PCR is the first assay on simultaneous, sensitive, specific, and reproducible detection of HBV, HCV, HEV, T. pallidum, and RNase P in a single tube. It could detect pathogens in blood during the window period of infection and is a good tool for effectively screening blood donors and early clinical diagnosis.

Hepatitis E virus in Cuba: A cross-sectional serological and virological study in pigs and people occupationally exposed to pigs

Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination.

Hepatitis E Virus Infection in Cancer Patients

Hepatitis E virus (HEV) infection in immunocompetent patients can lead to chronic hepatitis and liver failure. However, the burden of HEV infection in cancer patients is largely unknown. We studied the characteristics of HEV infection in patients at a tertiary care cancer center in the United States. This retrospective study included adult cancer patients with HEV infection diagnosed between September 2011 to September 2021. A total of 405 patients were tested for HEV, and 63 (16%) had detectable HEV IgG. Thirty-three patients (52%) were male, 43 were born in America (68%), 46 (73%) were screened for HEV because of pre-existing liver conditions, and 22 (35%) had hematological malignancies. Only 2 patients had detectable HEV RNA. The first patient had myelodysplastic syndrome and underwent allogeneic stem cell transplantation (HSCT). He developed elevated liver enzymes with HEV RNA 14,000 IU/mL (4.2 log IU/mL) 13 months after HSCT. After reducing immunosuppression, his HEV viremia resolved. The second patient had diffuse large B-cell lymphoma and underwent anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. She had elevated liver enzymes with HEV RNA 4,560,000 IU/mL (6.7 log IU/mL) 12 months after CAR T-cell therapy. She developed chronic HEV infection, and ribavirin treatment failed. Now she is being considered for salvage treatment with peginterferon alfa-2a and ribavirin. This study is the first report of chronic HEV infection in patients who received CAR T-cell therapy. HEV infection in cancer patients appears to be at least as common as in the general population. Cancer patients with hematologic malignancies may be at risk for HEV viremia and chronic infection refractory to antiviral treatment.

Viral hepatitis: A narrative review of hepatitis A–E

Viral hepatitis continues to be a major health concern leading to hepatic decompensation ranging from acute hepatitis to cirrhosis and hepatocellular carcinoma. The hepatic and extrahepatic manifestations are not only debilitating but also associated with a significant economic burden. Over the last two decades, the field of virology has made significant breakthroughs leading to a better understanding of the pathophysiology of viral hepatitis, which in turn has led to new therapeutic options. The advent of direct-acting antiviral agents changed the landscape of hepatitis C virus (HCV) therapy, and new drugs are in the pipeline for chronic hepatitis B virus (HBV) treatment. There has also been a significant emphasis on screening and surveillance programs, widespread availability of vaccines, and linkage of care. Despite these efforts, significant gaps persist in care, and there is a pressing need for increased collaboration and teamwork across the globe to achieve a reduction of disease burden and elimination of HBV and HCV.

Serology versus nucleic acid amplification to diagnose acute hepatitis E, United Kingdom, 2014-18

OBJECTIVES

Diagnosing hepatitis E infection usually involves specific IgM testing, but sensitivity/specificity concerns mean many guidelines and practices include confirmatory tests. We studied whether additional information confirmatory tests provide justifies their use.

METHODS

We examined 9,131 records of anti-hepatitis E IgM assays, 7,615 of IgG assays, and 1,726 of RT-PCR assays from our regional laboratory, spanning October 2014-October 2018. We paired 495 IgM assay results with a RT-PCR result. We examined whether IgM results predicted PCR results, reviewed discrepant pairs, and investigated the correlation between IgG and PCR results in patients with strongly reactive IgM assays.

RESULTS

Anti-hepatitis E IgM titres are bimodal. A high cut-off value optimises prediction of RNA detectability. 7/404 low-IgM samples had detectable RNA, 6 from immunosuppressed patients. 26/91 high-IgM samples did not have detectable RNA. In high-IgM samples, RNA detectability was not associated with IgG titre (one-tailed Mann-Whitney U test, p=0.14).

CONCLUSIONS

In immunocompetent patients, tests beyond IgM seldom add clinically useful information. In patients with immunocompromise, IgM and RNA could contribute information. Additional tests' extra costs/intervention delays cannot be justified. IgM assay cut-offs should reflect titres' bimodal distribution, with values standardised using international units.

The prevalence of HEV among non-A-C hepatitis in Qatar and efficiency of serological markers for the diagnosis of hepatitis E

BACKGROUND

The rapid growth of Qatar in the last two decades has attracted a large influx of immigrant workers who mostly come from HEV-hyperendemic countries. Thus, we aim to investigate the prevalence of HEV among acute non-A-C hepatitis patients in Qatar; and to evaluate the performance of four dominant commercial serological assays for HEV diagnosis.

METHODS

259 patients with non-A-C hepatitis were tested using the Wantai HEV-IgM, HEV-IgG, HEV-Ag ELISA kits, and the MP Biomedical HEV-Total Ab ELISA kit. ALT levels were tested and HEV RNA (viral loads) was performed using Taqman AmpliCube HEV RT-PCR kit (Mikrogen, Neuried, Germany). The performance of each kit was assessed according to the RT-PCR results.

RESULTS

HEV-RNA was detected in 23.1% of the samples. Most of these HEV-RNA-positive cases belonged to non-Qatari residents from the Indian subcontinent; India, Pakistan, etc. HEV-Ag, HEV-IgM, HEV-IgG, HEV-Total Ab were detected in 5.56%, 8.65%, 32.1%, and 34.2% of all tested samples, respectively. Elevated ALT levels were highly correlated with the HEV-Ag, HEV-IgM, HEV-RNA but not with the HEV-IgG and HEV-Total Ab. Although HEV-Ag was very specific (100%), yet its sensitivity was poor (36.7%). HEV-IgM demonstrated the best second marker for diagnosis of acute HEV after RT-PCR as jugged by the overall performance parameters: specificity (96.2%), sensitivity (71.4%), PPV (83.3%), NPP (92.7%), agreement with RT-PCR (91.0%), and Kappa-value (0.71).

CONCLUSION

Our study demonstrated a high prevalence of HEV virus in Qatar, mostly among immigrants from the Indian subcontinent. The HEV-IgM represents the best marker for detecting the acute HEV infection, where RT-PCR cannot be performed.

Viral hepatitis: A brief introduction, review of management, advances and challenges

Viral hepatitis represents a major public health hazard and is associated with significant global mortality. Over the last decade, there have been significant developments in the prevention and treatment of viral hepatitis. These changes have led to a situation whereby global elimination has become a realistic goal, fully endorsed by the World Health Organization (WHO). By 2030, the WHO aims to reduce viral hepatitis mortality by 65% and reduce new infections by 90% by 2030. These are ambitious targets and will only be met through a sustained programme. This will require expertise from hepatologists and virologists and the fields of public health and primary care. In this article, we review the causes of viral hepatitis, its management through prevention and treatments, and the most pressing challenges and recent advances.

Towards the Improved Accuracy of Hepatitis E Diagnosis in Vulnerable and Target Groups: A Global Perspective on the Current State of Knowledge and the Implications for Practice

The hepatitis E virus (HEV) is a positive single-stranded, icosahedral, quasi-enveloped RNA virus in the genus Orthohepevirus of the family Hepeviridae. Orthohepevirus A is the most numerous species of the genus Orthohepevirus and consists of eight different HEV genotypes that can cause infection in humans. HEV is a pathogen transmitted via the fecal-oral route, most commonly by consuming fecally contaminated water. A particular danger is the HEV-1 genotype, which poses a very high risk of vertical transmission from the mother to the fetus. Several outbreaks caused by this genotype have been reported, resulting in many premature births, abortions, and also neonatal and maternal deaths. Genotype 3 is more prevalent in Europe; however, due to the openness of the market, i.e., trade-in animals which represent a natural reservoir of HEV (such as pigs), there is a possibility of spreading HEV infections outside endemic areas. This problem is indeed global and requires increased hygiene measures in endemic areas, which entails special care for pregnant women in both endemic and non-endemic regions. As already highlighted, pregnant women could have significant health consequences due to the untimely diagnosis of HEV infection; hence, this is a population that should be targeted with a specific combination of testing approaches to ensure optimal specificity and sensitivity. Until we advance from predominantly supportive treatment in pregnancy and appraise the safety and efficacy of a HEV vaccine in this population, such screening approaches represent the mainstay of our public health endeavors.