IMMUNE ACTIVATION - THE ROLE OF PRO-INFLAMMATORY CYTOKINES IN INFLAMMATION, ILLNESS RESPONSES AND PATHOLOGICAL PAIN STATES

It has recently become accepted that the activated immune system commu nicates to brain via release of pro-inflammatory cytokines. This revie w examines the possibility that pro-inflammatory cytokines (interleuki ns and/or tumor necrosis factor) mediate a variety of commonly studied hyperalgesic states. We will first briefly review basic immune respon ses and inflammation. We will then develop the concept of illness resp onses and provide evidence for their existence and for the dramatic ch anges in neural functioning that they cause. Lastly, we will examine t he potential roles that both pro-inflammatory cytokines and the neural circuits that they activate may play in the hyperalgesic states produ ced by irritants, inflammatory agents, and nerve damage. The possibili ty is raised that apparently diverse hyperalgesic states may converge in the central nervous system and activate similar or identical neural circuitry.