| [ Summary ] |
Detection of the hepatitis E virus (HEV) RNA by reverse transcnption (RT)-PCR is the gold standard for diagnosis of hepatitis E. However, from a clinical point of view, serological diagnosis of hepatitis E by detection of specific antibodies against HEV (anti-HEV) is cheaper and more time-saving. We developed an enzyme-linked immunosorbent assay (ELISA) system to detect IgM and IgA classes of anti-HEV using purified recombinant ORF 2 proteins expressed in the pupae of silkworms as an antigen probe, and evaluated the specificity and sensitivity of these two assays. Among the 162 patients with hepatitis E, 158 (97.5 %) had anti-HEV IgM, while 160 (98.8 %) had anti-HEV IgA. Among the 3,782 control subjects, 17 (0.45 %) had anti-HEV IgM alone and 4 (0.11 %) had anti-HEV IgA alone. Periodic serum samples obtained from 15 patients with hepatitis E were tested for HEV RNA, anti-HEV IgM, and anti-HEV IgA. Although HEV RNA was detectable in the serum until 7 to 40 (21.4 ± 9.7) days after disease onset, both IgM and IgA anti-HEV antibodies were detectable until 37, 55, or 62 days after disease onset in 3 patients and up through the end of the observation period (50 to 144 days) in 12 patients. Obtained results indicate that anti-REV IgA is useful for serological diagnosis of hepatitis E with increased sensitivity and specificity and has a comparable duration of positivity with that of anti-HEV IgM. |