Serum interleukin 2 and soluble interleukin 2 receptor in chronic active hepatitis C: effect of interferon therapy.

T lymphocytes produce interleukin 2 (IL-2) associated with the expression of a soluble receptor for IL-2 (sIL-2R) on the surface of the cells, and these cytokines may contribute to hepatic injury in chronic active hepatitis C (CAH-C). Serum IL-2 and sIL-2R levels were analysed by enzyme linked immunosorbent assay in 22 patients (eight female, 14 male, mean age 42.6 years) with CAH-C. Eight patients had been given interferon alpha-2a (IFN alpha-2a), 3 million international units, three times weekly, for a mean of 12 weeks while the others were not on treatment. Serum IL-2 levels were 60.8 +/- 9.5 pg/ml, 66.6 +/- 5.7 pg/ml and 59.1 +/- 4.0 pg/ml in the treated patients, untreated patients and controls, respectively. Serum sIL-2R levels were 1631 +/- 194 pg/ml, 4016 +/- 1076 pg/ml and 1169 +/- 115 pg/ml in treated patients, untreated patients and controls, respectively. There were no significant differences in serum IL-2 levels between the groups (P > 0.05) while a significant difference was found in serum sIL-2R levels between untreated patients and controls (P = 0.0032). Serum sIL-2R levels were lower in patients treated with IFN alpha-2a than in untreated patients but this difference was not statistically significant. This preliminary study indicates that there are no significant changes in serum IL-2 levels in CAH-C patients, but that sIL-2R concentrations are raised in untreated patients though not in treated patients. High serum sIL-2R concentrations may have a role in the pathogenesis of CAH-C.