The effects of interferon-alpha on the production and action of other cytokines.

Various interferon-alpha (IFN-alpha) preparations, either as individual subtypes or natural mixtures, induce or inhibit expression of several other cytokines, as well as cytokine receptors and chemokines. The cytokines and receptors reportedly affected by IFN-alpha include interleukin-1 (IL-1), IL-2, IL-6, IL-8, IL-1 receptor, IL-1 receptor antagonist, tumor necrosis factor, tumor necrosis factor receptor, and IFN-gamma, all of which may amplify the effects of IFN-alpha treatment. The mechanism by which IFN-alpha induces expression of these cytokines is not clear. Some of the therapeutic and toxic effects associated with IFN-alpha therapy may be caused by the induction or inhibition of other cytokines and their respective cellular effects. Side effects including fever, anorexia, and fatigue can be caused by one or more of the cytokines induced by IFN-alpha. The response of different cell types, normal or malignant, to cytokines can vary. Such variation in cell type-specific responses may contribute to the diverse array of physiologic effects associated with IFN-alpha therapy. Further research is required to systematically uncover how other cytokines, receptors, or cellular factors contribute to the therapeutic and toxic effects of IFN-alpha.