Elevation of serum soluble interleukin-2 receptor levels in patients with hepatitis C virus infection.

To determine serum soluble interleukin-2 receptor (sIL-2 R) levels in hepatitis C virus (HCV) infection, serum sIL-2 R was measured in 260 subjects with chronic HCV infection, including 100 patients who had previously been treated with natural interferon (IFN) alpha, and in 51 HCV RNA-negative controls. Serum sIL-2 R levels in asymptomatic HCV carriers, patients with chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC) were significantly higher than those of healthy controls and subjects who were positive for anti-HCV and negative for HCV RNA (P < 0.01, respectively). Moreover, serum sIL-2 R levels were also significantly higher in patients with HCC than in other HCV RNA-positive groups. There was some correlation between serum sIL-2 R levels and histological activity index scores (r = 0.287, P < 0.01) and serum alanine aminotransferase levels (r = 0.272, P < 0.01). In patients in whom HCV RNA was eliminated following IFN treatment, serum sIL-2 R levels decreased to those seen in healthy controls by one year post treatment. Serum sIL-2 R levels increase due to HCV infection, and the amount of increase corresponds to the degree of inflammation.