Use of conserved sequences from hepatitis C virus for the detection of viral RNA in infected sera by polymerase chain reaction.

Three oligonucleotide primer combinations selected from the 5' noncoding, the nucleocapsid and the putative nonstructural regions of the hepatitis C virus genome were compared in a nested polymerase chain reaction assay with respect to sensitivity and specificity for the detection of viral RNA in chimpanzee-infected and human-infected sera. Sera from both the acute and the chronic phase of the infection were obtained from 13 animals inoculated with five different non-A, non-B hepatitis strains and from seven cardiac surgery patients who had non-A, non-B hepatitis develop after transfusion and who had been tested in parallel for the presence of hepatitis C virus RNA and anti-C 100-3. A total of 90% of the acute-phase and 100% of the chronic-phase sera tested positive for hepatitis C virus RNA when the 5' noncoding-derived or the nucleocapsid-derived combinations were used; only 58% and 56%, respectively, gave positive results with the putative nonstructural primers, whereas 33% and 71%, respectively, scored positive for C100-3. Thus polymerase chain reaction primers selected from either the highly conserved 5' noncoding or nucleocapsid-regions appear to provide the sensitivity and the specificity necessary to detect low levels of hepatitis C virus RNA in both chimpanzee-infected and human-infected sera.