DEMONSTRATION AND DISTRIBUTION OF HCV RNA SEQUENCES BY IN-SITU HYBRIDIZATION AND HCV-RELATED PROTEINS BY IMMUNOHISTOCHEMISTRY IN THE LIVER-TISSUE OF PATIENTS WITH CHRONIC HCV INFECTION

Nonisotopic in situ cytohybridization of HCV RNA was attempted in live r specimens from 12 chronically hepatitis C virus (HCV) infected patie nts, Oligonucleotides deduced from 5'-noncoding and core regions of th e HCV genome were labeled with digoxigenin and used on paraformaldehyd e-fixed frozen liver sections, The hybrids were visualized immunohisto chemically with alkaline phosphatase-conjugated anti-digoxigenin and a lkaline phosphatase substrate. These findings were correlated with the results of tissue immunohistochemistry for HCV antigens identified wi th specific mouse monoclonal antibodies developed against c22-3 antige n (Ag), a core-encoded protein, and c100-3 Ag, a NS4-encoded protein, and histologic assessment of each liver, HCV RNA detected in the above assay was predominantly cytoplasmic; it was detected in all 12 patien ts and in none of the controls, Tissue HCV RNA was associated with the presence of cytoplasmic (c100-3 Ag) and membrane (c22-3 Ag) expressio n of viral proteins in all 9 patients with histological evidence of ch ronic progressive liver disease as judged by the presence of piecemeal necrosis, and lobular and portal tract inflammation, Despite the pres ence of abundant HCV RNA, none of 3 patients without histological evid ence of chronic liver disease showed intrahepatocyte expression of vir al proteins, These findings support the view that tissue HCV antigens are markers of progressive damage and demonstrate that active liver di sease does not occur without such markers. It is proposed that synthes is of viral proteins and membrane accumulation of c22-3 Ag may be invo lved in the pathogenesis of hepatocyte injury in chronic hepatitis C i nfection.