Diagnostic performance of selected commercial HEV IgM and IgG ELISAs for immunocompromised and immunocompetent patients

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Abstract

Background

Hepatitis E virus (HEV) genotype 3 is recognised as an emerging pathogen in industrialised countries. The currently commercially available HEV-specific enzyme linked immunosorbent assays (ELISAs) are primarily designed for the detection of antibodies against genotypes 1 (Burma) and 2 (Mexico) and may not sensitively detect HEV genotypes 3 or 4.

Objectives

This study aimed to evaluate the analytical and clinical performances of eight commercially available HEV serum antibody immunoglobulin M (IgM)- and immunoglobulin G (IgG)-specific ELISAs for genotype 1 and 3 HEV infections in a clinical setting and to study the antibody responses against HEV of immunocompromised versus immunocompetent patient groups.

Study design

Analytical performance and diagnostic sensitivity and specificity were assessed using well-defined reference samples and samples from patients with polymerase chain reaction (PCR)-confirmed HEV infection (n = 88) and a specificity panel (n = 98).

Results

Limiting dilutions indicated that the highest analytical sensitivity in head-to-head comparison was measured for the Mikrogen_new IgG assay. Taking the serum working dilutions of each assay into account, the Wantai IgG assay was the most sensitive assay. Receiver operator curve (ROC) analysis showed area under the curve (AUC) values of 0.943, 0.964, 0.969, 0.971, 0.974 and 0.994 for the DSI, Mikrogen_old, MP Diagnostics, Mikrogen_new, Wantai and DiaPro anti-HEV IgM assays, respectively. The highest specificity of currently available assays was found for the IgM Wantai assay (>99%). If anti-HEV IgM and IgG results from each supplier were combined, DSI and Wantai assays were able to detect the highest number of (passed) HEV infections.

Conclusions

Our study showed that current commercial HEV ELISAs could be used to diagnose HEV genotype 3 infection adequately in a clinical setting.

Section snippets

Background

Hepatitis E virus (HEV) is a positive-sense, single-stranded RNA virus that causes sub-clinical, acute and chronic infections, characterised by hepatitis, though extra-hepatic manifestations have been described. Four genotypes are known to infect humans (genotype 1–4), the epidemiology and geographical distribution of which differs between genotypes 1–2 and 3–4. HEV genotype 3 and, to lesser extent, genotype 4 is recognised as an emerging pathogen in industrialised countries [1], [2] and it can

Objectives

We first aimed to evaluate the analytical and diagnostic performance of selected commercially available IgM and IgG ELISAs for the detection of both genotype 1 and 3 HEV infections using a well-defined serum panel of polymerase chain reaction (PCR)-confirmed HEV infected patients. Second, we targeted investigation of the HEV antibody responses in immunocompetent and immunocompromised patients.

Sample collection

The samples used in our retrospective study had been collected in the time period 2003–2011 during hospitalisation and routine visits by patients to our outpatient clinic for clinical assessments. Serum/ethylenediaminetetraacetic acid (EDTA)–plasma samples have been stored at −20 °C and −80 °C, respectively.

Sensitivity panel

In order to assess the analytical sensitivity we performed a twofold end-point titration of a genotype 1 and 3 HEV IgM and IgG antibody-positive serum, starting from 1/125 and 1/25,

Analytical sensitivity

IgM limiting dilutions indicated that the highest analytical sensitivity among the IgM ELISAs for genotype 1 was achieved by MP Diagnostics and Wantai assays. For genotype 3 IgM antibody titration, the Wantai assay was the most sensitive assay (Table 2). Remarkably, a wide variety of s/co ratios was observed, among which the IgM and IgG Wantai assay stood out (s/co ratios of 18 as upper limit of detection). IgG limiting dilutions indicated that the highest analytical sensitivity in head-to-head

Discussion

Autochthonous HEV infection, caused by genotype 3, is recognised as an emerging infectious disease in industrialised countries. Only limited data are available on the diagnostic performance of commercial IgM and IgG ELISAs or combination of these two, and the sensitivity of ELISAs coated with genotype 1 and 2 antigens is questioned for the detection of genotypes 3 and 4. Our study gives more insight into the diagnostic performance and antibody kinetics of commercial anti-HEV IgM and IgG assays

Funding

This work was supported by the Virgo consortium, funded by the Dutch Government (FES0908), by The Netherlands Genomics Initiative (NGI) (project number 050-060-452) and by the European Community Seventh Framework Programme (FP7/2007-2013) under project EMPERIE (Grant agreement No. 223498).

Conflicts of interest

S.D.P received travelling and accommodation expenses from Mikrogen. A.D.M.E.O. is chief science officer of Viroclinics Biosciences BV, a spin-out Erasmus MC contract research organisation that collaborates with pharmaceutical companies. The other authors have no conflicts of interest to disclose.

Ethical approval

This study was approved by the hospital medical ethical committee (MEC-2011-277).

Acknowledgements

We thank Claudia Mulders and Sandra Scherbeijn for technical assistance, Hans Kruining for his help with LIMS database searches and Jean-Luc Murk for his expert opinion. We thank Mikrogen and MP Products for providing the new IgM recomwell HEV ELISA and Diacheck anti IgM and IgG HEV ELISA.

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