A new PCR-based seroneutralization assay in cell culture for diagnosis of hepatitis E

A new method for the serological diagnosis of hepatitis E virus (HEV) infection based on neutralization of the virus in cell culture was developed. The test involves a short incubation of the virus in the presence of the serum sample to be tested and permissive cells. With viral replication being limited and without a cytopathic effect, viral growth in cells is evaluated by reverse transcription and PCR. The specificity of the test was established by studying sera from healthy individuals and patients with hepatitis living in France, where autochthonous hepatitis E is unknown. The kinetics and sensitivity of antibody detection were evaluated during the experimental infection of monkeys. Neutralizing antibodies were found in 79% of patients during an outbreak of hepatitis E and in 43% of patients with sporadic, acute non-A, non-B (without anti-hepatitic C virus antibodies) hepatitis. This neutralization assay is proposed as a confirmatory test for the available enzyme-linked immunosorbent assay (ELISA), which is now recognized as giving many false-positive reactions, and to improve identification of new hepatitis viruses since false-negative reactions with HEV ELISA are also encountered.