Anti-HEV Assays Evaluated for Diagnosing Acute Hepatitis E Infections

The performance of two anti-HEV IgG and IgM assays were assessed for diagnosing acute HEV infections in immunocompromised patients.

Hepatitis E virus is an emerging concern in immunocompromised patients, who may become chronically infected. No data were available for immunocompromised patients, who might not mount a good antibody response to HEV and might thus test negative for anti-HEV antibodies. The two anti-HEV assays evaluated in the study, published in the Journal of Clinical Virology online ahead of print October 15, 2013, were those from Adaltis and Wantai, the two main serological assays employed in Europe, specifically: EIAgen HEV IgG and IgM kits (Adaltis; Eurobio, France), based on synthetic antigens encoded by the ORF2 and ORF3 genes of HEV1 and HEV2; and the HEVIgM and IgG ELISA 3.0 Wantai kits (Wantai Biological Pharmacy Enterprise Co.; China), based on a recombinant HEV1 antigen, pE2. Tests were performed as recommended by the manufacturers.

Specificities were estimated by testing samples from 2 to 3 year-old children and blood donors and sensitivities were estimated by testing 40 immunocompromised patients acutely infected. Both anti-HEV IgM assays were highly specific (99.6% and 100%). The sensitivity of the Adaltis was 87.5%, and that of Wantai was 85%. The specificities of anti-HEV IgG Wantai (97.8%) and Adaltis tests (89.5%, p = 0.1) were similar but the Wantai test was more sensitive (45%) than the Adaltis test (15%, p < 0.001). None of the samples was anti-HEV IgM negative and IgG positive.

The authors, led by Dr. Florence Abravanel of the Centre Hospitalier Universitaire de Toulouse (University Hospital Center of Toulouse; Toulouse, France), concluded that these anti-HEV IgM assays performed well in immunosuppressed patients with acute hepatitis E and can be used as first line virological tools. Testing for anti-HEV IgG and IgM simultaneously at the acute phase did not improve the diagnostic performance. In contrast, molecular detection of HEV RNA appears essential to exclude an HEV infection in patients who are negative for anti-HEV IgM and to assess the evolution of hepatitis E three months thereafter.

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Centre Hospitalier Universitaire de Toulouse