Hepatic and extrahepatic hepatitis C virus replication in relation to response to interferon therapy

Abstract

Response to a 1‐yr course of interferon‐α2b was assessed in 18 patients with chronic hepatitis C virus infection in relation to clinical, biochemical and histological parameters and to the presence or absence of hepatitis C virus RNA and the presumed replicative form of the virus (negative‐strand hepatitis C virus RNA) in serum, liver and peripheral blood mononuclear cells. The findings were compared with those in seven untreated patients studied over the same period. At the start of the study, positive‐strand hepatitis C virus RNA was found in sera of all 25 patients, in livers of 24 and in peripheral‐blood mononuclear cells of 19 of 22 tested; negative strand was found in livers of 11 and in peripheral‐blood mononuclear cells of 15 of 22. Negative‐strand hepatitis C virus RNA was not found in the serum of any patient at any stage. All of the five treated patients considered to show complete response during the study period cleared hepatic hepatitis C virus RNA, and four also became seronegative, but three had evidence suggestive of viral replication in their peripheral‐blood mononuclear cells; two of these last patients subsequently relapsed. Loss of hepatic hepatitis C virus RNA was the only significant difference between these five and the seven partial and six nonresponders, but it is uncertain whether the observed changes were due specifically to interferon‐induced modulation of virus expression because similar (apparently spontaneous) changes were seen in four of the untreated patients. Although we noted a significant tendency for patients with milder disease at the outset to respond to interferon, histological severity of disease did not correlate with hepatitis C virus RNA parameters, none of which was predictive of response to treatment. The findings suggest that the presence and replication of the virus at extrahepatic sites may be the crucial factor in resistance to interferon therapy. (Hepatology 1994;20:1399–1404). Copyright © 1994 American Association for the Study of Liver Diseases