Performance of anti-HEV assays for diagnosing acute hepatitis E in immunocompromised patients
Section snippets
Background
The hepatitis E virus (HEV) has been recognized for decades as a major cause of outbreaks associated with faecal contamination of drinking water in developing countries. This pathogen is now also recognized as a major etiologic agent of acute hepatitis in industrialized countries that is transmitted zoonotically [1], [2].
HEV is an RNA virus with a single-stranded, positive sense approximately 7.2 kb genome containing partially overlapping open reading frames (ORFs). ORF1 encodes a nonstructural
Objectives
We have assessed the performance of two commercially available anti-HEV IgM and IgG tests, the Adaltis and the Wantai tests, the main serological assays employed in Europe, for diagnosing acute HEV infections in immunosuppressed patients.
Serum samples
All samples were collected in France. The specificities of the anti-HEV IgM assays were assessed by testing samples from 233 HEV-negative blood donors (HEV RNA negative, anti-HEV IgG negative with the HEV IgG ELISA kit; Wantai). Those of the anti-HEV IgG assays were assessed by testing samples from 180 2–3 year-old children hospitalized for surgery or trauma. The sensitivities of the HEV serological assays were determined using sera collected from 40 HEV immunocompromised patients whose sera
Performance of the anti-HEV IgM tests
Specificity was determined by testing 233 anti-HEV IgG and HEV RNA negative samples. The Wantai ELISA for HEV IgM found that 232 of them were negative (specificity: 99.6%, 95% confidence interval (95%CI): 98.7–100%), while the Adaltis EIAgen HEV IgM kit found that all 233 samples were negative (specificity: 100%, 95%CI: 99.8–100, p = 0.49) (Table 1).
We have assessed the sensitivity of the anti-HEV IgM tests by testing 2 panels of patients. The mean HEV RNA concentrations was 5.6 ± 1.1 log copies/ml
Discussion
We have evaluated the performance of two commercial anti-HEV IgG and IgM assays in immunocompromised patients during the acute phase. Both anti-HEV IgM assays were highly specific and sensitive (87.5% and 85%). The specificities of the anti-HEV IgG assays were similar but they were rather insensitive and did not contribute to the diagnosis of acute hepatitis E.
The presence of anti-HEV IgM is a marker of acute infection. A recent study evaluated the performance of six IgM anti-HEV enzyme
Funding
The National Reference Centre for Hepatitis E is supported by a grant from the French Public Health Authorities.
Competing interests
The authors declared no conflict of interest with respect to this manuscript.
Ethical approval
Not required.
Acknowledgements
We thank Delphine Gregoire and Sylvie Beaubatie for technical support. The English text was checked by Dr. Owen Parkes.
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