Detection of hepatitis C viral RNA by the polymerase chain reaction in serum of patients with post-transfusion non-A, non-B hepatitis.

Serial serum samples from cardiac patients with a history of chronic or resolved post-transfusion non-A, non-B hepatitis were analyzed by a combination of cDNA synthesis and the polymerase chain reaction (cDNA/PCR) to amplify HCV RNA. Analysis of sera drawn after the acute hepatitis episode from 8 of the patients who had an acute, resolving HCV infection showed no detectable levels of HCV RNA when primers from the NS3 region were used. Evaluation of these sera with primers from the 5'-untranslated (5'-UT) region revealed that one patient was positive for HCV RNA. Further analysis of serial serum samples available from two of these patients indicated that a resolved infection was associated with a disappearance of detectable HCV RNA after a peak level during the acute phase of the disease. In contrast, post-acute samples from 4 of 6 patients with symptomatic acute HCV infection evolving to chronicity were positive for HCV RNA using primers from the NS3 region, however, upon retesting with primers from the 5'-UT region, all 6 patients were found to be positive. Analysis of serial serum samples from 2 of these patients showed the persistence of HCV RNA in 70% of the samples. These two patients were subsequently treated with interferon alpha-2b. One patient resolved his disease and normalized his aminotransferase level during treatment and thereafter, while the other relapsed upon cessation of treatment. In these two patients, normalization of ALT levels was consistent with the absence of HCV RNA while relapse of disease was confirmed by the reappearance of detectable levels of HCV RNA. These results indicate the utility of HCV RNA as a marker for persisting HCV viremia and in differentiating patients with ongoing active HCV infection from those with an acute resolving disease.