Serial assay of hepatitis C virus RNA in serum for predicting response to interferon-alpha therapy.

To determine whether the loss of serum hepatitis C virus RNA (HCV-RNA) early in interferon therapy would indicate a sustained response to this agent, we detected serum HCV-RNA successively during and after therapy. Serum samples for detection of HCV-RNA were obtained serially from 36 patients with chronic hepatitis C treated with interferon-alpha. In 28 of these patients, results of the assay were compared with genotypes and quantitative levels of HCV-RNA in serum before therapy. HCV-RNA was detected by a reverse transcription polymerase chain reaction using the 5'-noncoding region as a primer. Genotypes were determined by using type-specific primers, and serum levels of HCV-RNA were determined by a competitive reverse transcription polymerase chain reaction (RT-PCR). HCV-RNA disappeared from serum in eight of 10 responders (80%), but in only one of the 26 nonresponders (3.8%) at the second week of therapy (P < 0.0005). The time until the disappearance of HCV-RNA was correlated with the serum level of HCV-RNA present before therapy (P < 0.05). The early disappearance of HCV-RNA from serum during interferon therapy was useful in predicting a sustained response in patients with chronic hepatitis C.