One-point quantitative determination of pretreatment serum hepatitis C virus RNA predicts long-term responsiveness to high-dose interferon therapy

We determined quantitative values of serum hepatitis C virus RNA by branched DNA amplification assay in 52 consecutive patients with chronic hepatitis C immediately before high-dose treatment with interferon-alpha. Thirty-four out of 52 patients had >106.3 (≈2 × 106) equivalents/ml of viral genomes. Only three (8.8%) out of these 34 were long-term responders, while 16 (88.9%) out of 18 patients with ≤106.3 equivalents/ml of viral genomes were long-term responders (P < 0.001). When patients were classified according to genotypes, only 11 of 42 patients with genotype II hepatitis C virus showed sustained normal serum alanine aminotransferase activities for more than 1 year after interferon therapy, while eight out of nine patients with genotypes III or IV had sustained remission. In 42 patients with genotype II, 11 had viral genomes of ≤106.3 equivalents/ml and 10 (90.9%) out of these 11 had long-term response, while only one (3.2%) out of 31 patients with >106.3 equivalents/ml was a long-term responder (P < 0.001). By determining HCV-RNA levels in serum, we could thus predict long-term responsiveness to high-dose interferon therapy in 47 (90.4%) out of 52 chronic hepatitis C patients, and 40 (95.2%) out of 42 patients with genotype II hepatitis C virus. Our results indicate that quantitative measurement of hepatitis C viral genomes in pretreatment serum by the simple branched DNA amplification assay is an excellent method for predicting long-term responsiveness to interferon treatment.