Detection of interferon-alpha expression by PCR in patients with chronic hepatitis C and hepatitis non-A, non-B.

The polymerase chain reaction (PCR) was used to examine expression of interferon-alpha (IFN A) genes in general and the expression of messenger RNA (mRNA) encoding the subtypes IFN-alpha-2 and IFN-alpha-4 in blood and liver biopsy samples from patients with chronic hepatitis C or hepatitis non-A, non-B (HC/HNANB) infection entered into a trial of IFN-alpha-2a therapy. Peripheral blood mononuclear cells (PBMC) from healthy controls and HC/HNANB infected patients were studied for their capacity to produce transcripts encoding IFN-alpha after stimulation with Sendai virus. Expression at the level of mRNA for IFN A and the subtypes IFN A2 and A4 was detected in both controls and HC/HNANB infected patients PBMC and no significant difference was seen in expression of IFN A transcripts or level of total IFN-alpha secreted into culture supernatants between controls and patients. Interferon A, and specifically IFN A2 and IFN A4 transcripts were detected in a high proportion of liver biopsies from patients with HC/HNANB infection. The presence of IFN A mRNA (and specifically IFN A2 and IFN A4) showed no correlation to histological improvement nor response to therapy. The use of PCR to detect those IFN A genes that are not expressed, thereby identifying subtypes that may be lacking, could be the key to the choice of IFN-alpha subtypes that are used for effective therapy.