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

Abstract 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‐α‐2 and IFN‐α‐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‐α‐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‐α 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‐α 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‐α subtypes that are used for effective therapy.