title: Human Interferon Regulatory Factor 2 Gene Expression is Induced in Chronic Hepatitis C Virus Infection-A Possible Mode of Viral Persistence.
abstract: BACKGROUND
  The interferon regulatory factors (IRFs) are a family of transcription factors known to be involved in the modulation of cellular responses to interferons (IFNs) and viral infection. While IRF-1 acts as a positive regulator, IRF-2 is known to repress IFN-mediated gene expression. The increase in the IRF-1/IRF-2 ratio is considered as an important event in the transcriptional activation of IFN-α gene toward development of the cellular antiviral response.
  
  
  OBJECTIVE
  This study was performed to assess the expression of IRF mRNAs along with the expression level of IFN-α, its receptor (IFNAR-1), and the signal transduction factor (STAT-1) in treatment naive hepatitis C virus (HCV)-infected subjects.
  
  
  METHODS
  Thirty-five chronically infected (CHC) patients and 39 voluntary blood donors as controls were included in the study. Quantification of HCV-RNA (ribonucleic acid) and genotyping were done by real-time polymerase chain reaction (PCR) and hybridization assays, respectively, using patient's serum/plasma. In both controls and patients, the serum level of IFN-α and IFN-α was measured by flow cytometry. Target gene expressions were studied by retro-transcription of respective mRNAs extracted from peripheral blood mononuclear cells (PBMCs) followed by PCR amplification and densitometry. Minus-strand HCV-RNA as a marker of viral replication in PBMCs was detected by an inhouse PCR assay.
  
  
  RESULTS
  Both IRF-1 and IRF-2 genes were significantly enhanced in CHC than in control subjects (P < 0.001). A significant positive correlation (r (2) = 0.386, P <0.01) was obtained between higher IRF-2 gene expression and increasing level of HCV-RNA. Chronically infected subjects (13%) harboring replicating HCV in PBMCs showed no significant differences in gene expressions than the subjects without HCV in PBMCs.
  
  
  CONCLUSIONS
  Our findings indicate that HCV modulates host immunity by inducing IRF-2 gene to counteract IRF-1-mediated IFN-α gene expression. Since the IRF-2 gene is known to encode oncogenic protein, the role of IRF-2 in CHC patients developing hepatocellular carcinoma warrants further studies.
authors.affiliation: Asian Health Care Foundation, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Rathindra M
authors.initials: RM
authors.lastname: Mukherjee
authors.affiliation: Asian Health Care Foundation, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Budhapriyavilas
authors.initials: B
authors.lastname: Bansode
authors.affiliation: Asian Health Care Foundation, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Puja
authors.initials: P
authors.lastname: Gangwal
authors.affiliation: Asian Health Care Foundation, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Aparna
authors.initials: A
authors.lastname: Jakkampudi
authors.affiliation: Asian Health Care Foundation, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Panyala B
authors.initials: PB
authors.lastname: Reddy
authors.affiliation: Asian Institute of Gastroenterology, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Padaki N
authors.initials: PN
authors.lastname: Rao
authors.affiliation: Asian Institute of Gastroenterology, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Asian Institute of Gastroenterology, Somajiguda - 500082, Hyderabad, AP, India.
authors.forename: D
authors.initials: D
authors.lastname: Nageshwar Reddy
keywords: CHC, chronic hepatitis C; CLD, chronic liver disease; Gene expression; HBV, hepatitis B virus; HBsAg, hepatitis B virus surface antigen; HCC, hepatocellular carcinoma; HCV, hepatitis C virus; IFN, interferon; IRES, internal ribosomal entry site; IRF, interferon regulatory factors; PBMC, peripheral blood mononuclear cells; PCR, polymerase chain reaction; SVR, sustained virological response; VCAM, vascular cell adhesion molecule; hepatitis C virus; interferon regulatory factor 2; interferon-alfa; peripheral blood mononuclear cells