Long-term carriage of hepatitis C virus with normal aminotransferase after interferon treatment in patients with chronic hepatitis C.

Studies were undertaken to investigate whether interferon therapy could induce hepatitis C virus (HCV) carriage with normal serum alanine aminotransferase (ALT) values using an assay that combined reverse transcription and polymerase chain reaction. The subjects studied were 53 patients with chronic active hepatitis C who received interferon (alpha, 33 cases; beta, 20 cases) therapy. All were seropositive for HCV RNA prior to therapy. In all 22 complete responders, whose ALT levels fell to normal during therapy and for at least 24 weeks after therapy, HCV RNA became persistently negative except in two cases. The two had sustained viremia on treatment and for 1.0-1.5 years of follow-up, although their biochemical tests were normal. In 15 patients with a transient response in whom the disease recurred when interferon was stopped, HCV RNA was undetectable in 80% of the cases at the end of therapy, but the virus reappeared with subsequent elevation of ALT in all patients. However, 3 patients in this group had normal enzyme levels with viremia for 2.1-2.8 years of follow-up after acute deterioration of illness. In 16 patients who did not respond to interferon, HCV RNA was persistently positive during and after therapy. These findings suggest that interferon therapy induces a long-term carrier state of HCV infection with normal ALT levels in some patients.