Serum levels of soluble interleukin-2 receptors and effects of interferon-alpha for patients with chronic hepatitis C virus.

To characterize the role of serum soluble interleukin-2 receptor (sIL-2R) in hepatitis C virus (HCV) infection, the level of sIL-2R was measured by ELISA in 117 subjects with chronic HCV infection and in 23 healthy controls. HCV RNA was detected by polymerase chain reaction in all subjects with HCV infection. Forty-seven patients with chronic hepatitis and 10 with liver cirrhosis were treated for six months with natural interferon-alpha. The sIL-2R levels of 40 asymptomatic HCV carriers (632 +/- 340 units/ml), 47 patients with chronic hepatitis (547 +/- 204 units/ml), 10 with cirrhosis (679 +/- 239 units/ml, and 20 with hepatocellular carcinoma (1145 +/- 487 units/ml) were significantly higher than those of healthy controls (380 +/- 191 units/ml) (P < 0.05, respectively). The levels of sIL-2R increased, as did the histological activity index scores (r = 0.348, P < 0.01). The level of sIL-2R rose after the initial administration of interferon in all 57 patients. In patients whom HCV RNA was eliminated from the sera within a six-month follow-up after cessation of treatment, the level of sIL-2R reverted to basal values, but in patients in whom HCV RNA was not eliminated the value was significantly higher than that before treatment. These results suggest that monitoring serum sIL-2R in patients with chronic HCV infection treated with interferon may provide information concerning the possibility of the elimination of HCV RNA.