Hepatitis B E antigen detection in formalin-fixed liver biopsy specimens. A tool to investigate wild-type and E-minus variant HBV infection.
The aim of this study is to investigate whether hepatitis B e antigen (HBeAg) reactivity can be detected on formalin-fixed, paraffin-embedded liver tissue, and whether immunohistochemical detection of intrahepatic HBeAg may help to distinguish between "wild-type" and "eminus" hepatitis B virus (HBV) infection. Liver biopsy specimens were analyzed from 27 patients with chronic type B hepatitis: 12 patients had serum HBeAg (group A), and 15 patients were anti-HBe positive (group B). Part of each biopsy fragment was processed for histologic and immunohistochemical studies, and a part was used for HBV-DNA analysis. Dewaxed sections from each specimen were tested with a specific monoclonal anti-HBe antibody; then a Biotin-Streptavidin kit was used as detection system. HBeAg was revealed in 10 of 12 cases of group A and in 6 of the 15 cases of group B. Pre-core region of HBV genomes, isolated from each biopsy specimen, was analyzed by direct sequencing: 10 cases of group A were found to be infected by wild-type HBV alone and 2 cases by both wild and e-minus HBV types. In group B, all the 6 cases with intrahepatic HBeAg reactivity were found to be infected by mixed viral population, whereas the 9 cases negative for such reactivity were found to be infected by e-minus HBV alone. These results show that HBeAg can be detected in formalin-fixed, paraffin-embedded liver specimens, and the method is sensitive and specific. Because the presence of HBeAg in the liver indicates a wild-type HBV infection, and the lack of detection of such antigen in the hepatocytes of anti-HBe positive subjects correlates with unmixed e-minus HBV infection, the authors conclude that this technique is a useful tool for recognizing the viral strains that infect patients with chronic type B hepatitis.
Dipartimento di Patologia Umana, Università di Messina, Italy.
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D000293:Adolescent; D000328:Adult; D000368:Aged; D001483:Base Sequence; D001706:Biopsy; D005404:Fixatives; D005557:Formaldehyde; D014644:Genetic Variation; D016679:Genome, Viral; D006509:Hepatitis B / Q000276:immunology* / Q000821:virology; D006513:Hepatitis B e Antigens / Q000302:isolation & purification*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D016133:Polymerase Chain Reaction; D014758:Viral Core Proteins / Q000235:genetics
D005404:Fixatives; D006513:Hepatitis B e Antigens; D015345:Oligonucleotide Probes; D014758:Viral Core Proteins; D005557:Formaldehyde