HEPATIC EXPRESSION OF HEPATITIS-C VIRUS-RNA IN CHRONIC HEPATITIS-C - A STUDY BY IN-SITU REVERSE-TRANSCRIPTION POLYMERASE CHAIN-REACTION

Hepatitis C virus (HCV) replicates at a low rate, and this makes its d etection and intrahepatic localization difficult; To evaluate the clin ical implications and effect of interferon alfa (IFN-alpha) therapy on hepatic expression of HCV RNA, HCV RNA was detected by in situ revers e-transcription polymerase chain reaction (IS-RT-PCR) in formalin-fixe d paraffin-embedded liver sections from 26 patients with chronic hepat itis C, Results were compared with RT-PCR of HCV RNA extracted from li ver sections/tissue. Twenty-four paired post-IFN-alpha treatment biops y specimens were also assessed, Using RT-PCR of the extracted RNA as a positive standard and non-HCV liver sections as the negative standard , the sensitivity and specificity of IS-RT-PCR were 69% and 100%, resp ectively, HCV RNA was detected in the cytoplasm of hepatocytes (median , 5% hepatocytes positive; range, 0 to 35%) and very occasionally in i nfiltrating mononuclear cells, There was no correlation between hepati c expression of HCV RNA and the clinical, biochemical parameters, tota l and activity scores of histology activity index. Presence of HCV RNA in liver as detected by IS-RT-PCR was associated with higher serum HC V RNA levels (4.9 x 10(6) vs, 0.4 x 10(6) genome Eq/mL, P < .01), Ther e was no difference in the pretreatment proportion of HCV RNA-positive hepatocytes among patients with different biochemical responses to IF N-alpha therapy, In the posttreatment samples, HCV RNA was undetectabl e by IS-RT-PCR in 16 of 24 patients (P < .01), including all 4 patient s who had complete and sustained response (SR). We conclude that HCV R NA was detected by IS-RT-PCR in 0 to 35% of hepatocytes in patients wi th chronic HCV infection, detection of HCV RNA in liver by IS-RT-PCR w as associated with higher viremia levels, and IFN-alpha therapy reduce d hepatocytic expression of HCV RNA.