Interferons and inflammation.

The local inflammatory response to exogenous or endogenous agents is regulated by various humoral factors. Amongst these, the cytokines represent a prominent group to which belong not only cytotoxins, chemotactic factors, and cellular growth factors, but also the interferons. Evidence is reviewed indicating that, at the local level, interferon-gamma (IFN-gamma) constitutes a positive factor triggering or promoting the inflammatory response. Studies employing monoclonal antibodies against IFN-gamma indicate that inflammatory agents, such as bacterial endotoxin, induce local production of IFN-gamma, which acts as an up-regulator of the primary phase of the inflammatory response. Antibodies against IFN-alpha/beta, on the contrary, have so far not been found to affect inflammation. Systemic interferons, on the other hand, seem to fulfil a down-regulating role, as evidenced by the observation that exogenously administered IFN-alpha, -beta, and -gamma inhibit local inflammation.