IN-SITU HYBRIDIZATION STUDIES OF HEPATITIS-A VIRAL-RNA IN PATIENTS WITH ACUTE HEPATITIS-A

In situ hybridization with oligonucleotide probes has been used to loc alise hepatitis A virus RNA genomic sequences in formalin-fixed and ro utinely processed human liver biopsies from three patients. Using radi olabelled Sulphur-35 antisense probes, viral genomic sequences were fo und in all three cases, but signal intensity was greatest in cases 1 a nd 2 with fulminant hepatitis, and was minimal in the third case of re solving hepatitis biopsied 2 months after acute illness. Localisation showed the viral RNA to be present in hepatocytes, sinusoidal cells an d inflammatory cells in and around the portal tracts. Both cases showe d signal in similar cell types, but the distribution of staining was p redominantly periportal in case 1, whereas lobular staining was more a pparent in case 2. Hybridization with sense polarity probes failed to detect any evidence of replicative intermediates of antigenomic viral RNA. The presence of hepatitis A RNA in phagocytic cells was confirmed using immunohistochemistry for a macrophage marker, CD68, combined wi th in situ hybridization. In all cases the signal was predominantly cy toplasmic, and this was confirmed with the use of tritiated probes. (C ) Journal of Hepatology.