In subjects with antibody to hepatitis C virus a high serum level of interleukin-2 soluble receptor suggests activity of liver disease

The hepatitis C virus (HCV) is an RNA virus without apparent cytopathic effects, and hepatocellular damage in chronic infection is generally believed to be immune-mediated by cytotoxic T lymphocytes. Activated T cells release the soluble form of the interleukin-2 (IL-2) receptor (sIL-2R) and its concentration is correlated with the degree of lymphocyte activation. We measured sIL-2R in 69 subjects: 24 healthy repeat blood donors (group I), 17 HCV carriers without liver damage (group II) and 28 patients with HCV-related chronic active hepatitis (group III). There was no significant difference between sIL-2R levels in patients of group I (36.5±14.6Uml^–1) and group II (46.8±17.4Uml^–1), and the levels for both of these groups were significantly lower than those observed in the patients with active HCV, group III (176.9±59.5Uml^–1). Hence, among HCV-infected subjects (HCV RNA positive) with persistently normal alanine aminotransferase (ALT) levels, the plasma levels of sIL-2R are normal, but, in patients (HCV RNA positive) with HCV-related chronic active hepatitis there are increased plasma levels of sIL-2R. We conclude that in HCV infection high levels of sIL-2R are related to activity of the disease rather than to virus replication. In patients with HCV-related chronic liver disease, the sIL-2R concentration may be a useful marker of disease activity.