Comparative analysis of serological markers of chronic delta infection: HDV-RNA, serum HDAg and anti-HD IgM.

To study the concordance, sensitivity and specificity of HDV-RNA determination by molecular hybridization, serum HDAg by immunoblot and anti-HD IgM by commercial enzyme immunoassay as compared to intrahepatic HDAg detection by an immunoperoxidase method, a statistical analysis was applied to the results of serum sample and liver biopsy determinations in 50 patients with chronic delta hepatitis (38 positive to tissue HDAg and 12 negative). Of the 38 patients with hepatic HDAg, HDV-RNA was found in 31 (82%), serum HDAg by immunoblot in 27 (71%) and anti-HD IgM in 33 (87%). Among the 12 patients without hepatic HDAg, one was found with serum HDAg using the immunoblot technique, two (17%) had HDV-RNA, and 7 (58%) had anti-HD IgM. Serum HDAg determination by immunoblot was the most specific test, followed by HDV-RNA analysis. The least specific was the anti-HD IgM technique. The anti-HD IgM test was the most sensitive, followed by HDV-RNA and serum HDAg. The concordance with intrahepatic HDAg detection was highest for HDV-RNA determination, followed by HDAg in serum. The least degree of concordance was found with anti-HD IgM determination. These results suggest that the determination of HDV-RNA by the hybridization method can be of great value for the diagnosis and monitoring of chronic delta hepatitis.