Semiquantification by Amplicor assay of hepatitis C virus genome during therapy.

In this study, 42 hepatitis C virus (HCV)-infected patients included in different treatment protocols were assessed by semiquantitative Amplicor assay to evaluate the changes in HCV-RNA titer during antiviral therapy. Amplicor detected change to negative HCV-RNA at the end of treatment in four biochemically responding patients; a decrease in HCV-RNA titer from base line was observed in 2/6 complete responder patients, in 7/11 responders with relapse, and in 6/21 nonresponder patients. Furthermore, Amplicor also detected an increase in HCV-RNA titer from the end of treatment to the follow-up samples in 3/6 complete responder patients, in 7/11 responders with relapse, and in 3/6 nonresponder patients in whom HCV-RNA titer at the end of treatment was lower than in the basal sample. None of the nonresponder patients showed a change to negative HCV-RNA either at the end of treatment or at follow-up. When comparing the detection of HCV-RNA by this semiquantitative method and by nested-PCR, we found a concordance in 113/118 polymerase chain reaction (PCR) results (96%), including three negative results by both methods. With respect to the noncorrelated results, negative PCR samples were found to be positive by Amplicor assay in three cases (correspondent to final samples of treatment); by contrast, two positive PCR samples were found to be negative by Amplicor assay (correspondent to final and follow-up samples of different patients).