Serological response to hepatitis E virus genotype 3 infection: IgG quantitation, avidity, and IgM response.
Sequential sera were collected from 18 acute cases of UK-acquired hepatitis E. The virus strains in all cases were of genotype 3. The IgM and IgG response to acute infection were documented over time using EIA kits based on a peptide antigen, pE2, which is derived from a genotype 1 strain of hepatitis E virus (HEV). Ninety-five percentage of acute sera were IgM positive; after 6 months or more only 12% remained positive. The kit was adapted to quantify the IgG response (in WHO U/ml) and to determine antibody avidity. Following acute infection, anti-HEV IgG concentrations rose between 6.9- and 90-fold. IgG avidity was low (<25%) in most acute sera. After 6 months IgG avidity was greater than 50% in all cases. One patient with a poor IgM response and high avidity antibody in acute sera may have had a second HEV infection. Taken together, these results confirm that the pE2-based EIA kits are suitable for diagnosing acute HEV genotype 3 infection. With simple modifications the IgG kit can measure anti-HEV concentration and avidity, which can be used to confirm acute infection.
Department of Clinical Microbiology, Royal Cornwall Hospital Trust, Truro, Cornwall, UK. richard.bendall@rcht.cornwall.nhs.uk
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D000915:Antibody Affinity; D005838:Genotype; D006508:Hepatitis Antibodies / Q000097:blood*; D018963:Hepatitis Antigens; D016751:Hepatitis E / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D016752:Hepatitis E virus / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D012367:RNA, Viral / Q000097:blood; D011933:Reagent Kits, Diagnostic; D014766:Viremia / Q000821:virology
D006508:Hepatitis Antibodies; D018963:Hepatitis Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic