Evaluation of an antigen-capture EIA for the diagnosis of hepatitis E virus infection.
An enzyme immunoassay (EIA) has been developed for hepatitis E virus (HEV) antigen (HEV-Ag) detection and marketed in China. This study aimed to evaluate the sensitivity of the assay and assess the value of HEV-Ag detection in the diagnosis of HEV infection in comparison with HEV RNA detection. Using serial dilutions of a genotype 4 HEV strain, significant correlation was found between the EIA (S/CO) and HEV RNA (IU/mL) concentration in the range 10(3.5) to 10(0.5) IU/mL HEV RNA, the Pearson correlation coefficient r approached 0.97. The EIA detection limit was 54.6 IU/mL, compared to 24 IU/mL for HEV RNA using real-time RT-PCR. In clinical samples from hepatitis E patients, the HEV-Ag and HEV RNA positivity rates were 55.6% (65/117) and 60.7% (71/117) in sera and 76.7% (56/73) and 84.9% (62/73) in stools, and the concordance of these two markers was 77.8% in sera and 80.8% in stools. In serum samples, the HEV-Ag positivity rate and the concordance between HEV-Ag and HEV RNA were inversely proportional to the presence of anti-HEV antibody. The presence of anti-HEV IgG could reduce the S/CO of the HEV-Ag EIA. These results reveal a significant correlation between the detection of HEV-Ag and HEV RNA. The sensitivity of the HEV-Ag EIA was lower than real-time RT-PCR but could be higher than conventional nested RT-PCR. Therefore, the detection of HEV-Ag in serum and faeces is valuable for the diagnosis and prognosis of HEV infection in developing regions where real-time RT-PCR is not available.
College of Life Sciences, Jilin University, Changchun, China.|Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China.
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C
Zhao
Health Science Center, Hebei University, Baoding, China.
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Y
Geng
Division of Medicine, University College London Medical School, London, UK.
T J
TJ
Harrison
College of Life Sciences, Jilin University, Changchun, China.
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Huang
College of Life Sciences, Jilin University, Changchun, China.
A
A
Song
College of Life Sciences, Jilin University, Changchun, China.|Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China.
Y
Y
Wang
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis*; D001769:Blood / Q000821:virology; D002681:China; D005243:Feces / Q000821:virology; D016751:Hepatitis E / Q000175:diagnosis*; D016752:Hepatitis E virus / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
D000956:Antigens, Viral; D012367:RNA, Viral
HEV ORF2 protein; HEV antigen; diagnostic marker; enzyme immunoassay; hepatitis E virus