A valuable antigen detection method for diagnosis of acute hepatitis E

Area of Science:

• Hepatology
• Virology
• Immunology

Background:

• Hepatitis E virus (HEV) poses a significant public health challenge.
• Current diagnostic methods for active HEV infection include detecting anti-HEV IgM antibodies and HEV RNA.
• Limitations exist in the sensitivity and duration of detection for existing diagnostic markers.

Purpose of the Study:

• To develop and validate an improved enzyme-linked immunosorbent assay (ELISA) for detecting HEV antigen.
• To assess the diagnostic performance of the new HEV antigen assay compared to existing methods (IgM, RNA).
• To evaluate the utility of HEV antigen detection for diagnosing acute hepatitis E.

Main Methods:

• Development of an enhanced ELISA utilizing a high-affinity monoclonal antibody (MAb 12F12) for HEV antigen capture.
• Testing the assay's linear range and positive detection period in HEV-infected monkeys.
• Comparative analysis of HEV antigen, IgM, and RNA detection rates in serum samples from patients with acute hepatitis E.

Main Results:

• The improved ELISA demonstrated a linear range of 6.3 × 10^3 to 9.2 × 10^5 RNA copies/ml.
• HEV antigenemia was detected for an average of 3 weeks longer in infected monkeys compared to previous reports, covering most of the acute phase.
• In acute hepatitis E patients, the HEV antigen assay achieved a 100% positive detection rate (16/16) in initial serum samples, outperforming IgM and RNA detection (81%, 13/16 each).
• The assay identified HEV antigen in patients with IgM-negative, RNA-negative results, suggesting its utility when nucleic acid is degraded.

Conclusions:

• The novel HEV antigen detection method shows high sensitivity and an extended detection window.
• This improved ELISA offers comparable performance to RNA detection and can be a valuable tool for diagnosing acute hepatitis E.
• The assay is particularly useful in cases where HEV RNA may be degraded or IgM antibodies are not yet detectable.