Performance of anti-HEV assays for diagnosing acute hepatitis E in immunocompromised patients

Hepatitis E virus is an emerging concern in immunocompromised patients, who may become chronically infected. This prompted us to assess the performance of two anti-HEV IgG and IgM assays for diagnosing acute HEV infections. The specificities of the assays were estimated by testing samples from 2 to 3 year-old French children and blood donors and their sensitivities 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. We conclude that these anti-HEV IgM assays performed well in immunosuppressed subjects 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 3 months thereafter.