Interferons and their role in inflammation

Cytokines are pleiotropic molecules showing a wide variety of biologic func tions on various cells and tissues, and several different cytokines exert s imilar and overlapping functions on certain cells. Interferons (IFNs), amon g the first cytokines identified, play a crucial role in human disease. The IFN cytokine family consists of type I IFNs (IFN-alpha and IFN-beta) and t ype II IFN (IFN-gamma). In the first decades of IFN research, type I IFNs w ere considered primarily as viral inhibitors, whereas type II IFN, also ter med "immune IFN", was generally considered to be uniquely involved in immun e reactions. This view has changed considerably in the last years. The impo rtance of type I IFNs in inflammation, immunoregulation and T-cell response s has been identified and has changed dramatically our interpretation of th e biological relevance of type I and II IFNs, Recent data suggest that IFN- alpha is a multifunctional immunomodulatory cytokine with profound effects on the cytokine cascade including several anti-inflammatory properties, whe reas IFN-gamma remains a classical proinflammatory cytokine. These differen t effects on critical mediators of inflammation may also explain why type I and II IFNs are clinically successful in different diseases. These newly i dentified immunoregulatory and anti-inflammatory functions of type I IFNs m ay be of importance in the treatment of diseases such as chronic viral hepa titis or multiple sclerosis and help to explain some of the mechanisms of I FNs.