Differential induction of serum interleukin-6 and -12 by interferon-alpha and -beta administration in chronic hepatitis C patients.

ABSTRACT

Interferon (IFN) is widely used to manage chronic hepatitis C virus (HCV) infections. It contributes to the production of various cytokines, and alters cytokine interactions in vivo. Among them, interleukin (IL)-12, is thought to shift the immune system to Th-1 dominance and to, therefore, have a beneficial effect on eradication of HCV. On the other hand, IL-6 seems to be related to the acute inflammatory phenomenon, such as fever accompanied with IFN therapy. We studied the time courses of the serum IL-12 and IL-6 levels of patients with HCV infections treated with either IFN-alpha or IFN-beta. On the first day, both IFN-alpha and IFN-beta significantly induced serum IL-6, but when the administration was repeated, the serum IL-6 levels gradually decreased in both the IFN-alpha and the IFN-beta groups. The serum IL-6 levels correlated well with the daily peak body temperature of the patients, which also went down with repeated IFN administration. Serum IL-12 production was induced by IFN-alpha not by IFN-beta. The induced IL-12 decreased to baseline by repeating IFN-alpha administration. These results suggested that IFN-alpha and IFN-beta induce cytokine production in a different manner, and that their effect on cytokine interactions is short-term and reduced by repeated administration. Therefore, the induction of serum IL-12 production by IFN did not seem to have a critical effect during the early stage of IFN therapy.