Interferon-gamma, interleukin (IL)-2 and IL-2 receptor expressions in hepatitis C virus-infected liver

Cytokine response to viral infection can be of critical importance in the host defense against virus. Interferon (IFN)-gamma and interleukin (IL)-2 have wide ranges of activities in host defense mechanisms. Therefore, these cytokine genes in the liver were investigated in a series of patients with hepatitis C virus (HCV) infection using a reverse transcribed-polymerase chain reaction (RT-PCR). Total RNA was purified from liver biopsies, reverse transcribed to cDNA, amplified by specific primers, and the products were detected by agarose gel and slot blot hybridization. All samples from acute hepatitis (AH; n = 4) and chronic hepatitis patients (CH; n = 19) were positive for IFN-gamma at varying degrees. AH patients showed strong signals compared to CH patients, liver cirrhosis (LC; n = 12; 72% positive) patients, and hepatocellular carcinoma (HCC; n = 21; 19% positive) patients. IL-2 gene was undetectable in all patients tested. IL-2 receptor (IL-2R) was detectable in AH, CH and LC patients but not in HCC patients. We conclude that IFN-gamma has important roles in the cytokine network that indeed present in the liver of HCV patients while the presence of IL-2R gene may indicate that the signaling pathway for IL-2 is intact.