Immune-to-central nervous system communication and its role in modulating pain and cognition: Implications for cancer and cancer treatment

This paper reviews the nature of communication from the immune system to the brain and some implications of this communication for phenomena that are not ordinarily considered to be modulated by immune function. Pro-inflammatory cytokines released by activated immune cells signal the brain by both blood-borne and neural routes, leading to alterations in neural activity. The cascade of altered neural activity includes the induction of pro-inflammatory cytokines within the brain and spinal cord. The cytokines in the brain, specifically in the hippocampus, interfere with the consolidation of memory, while the cytokines within the spinal cord exaggerate pain. Activation of this immune-to-central nervous system pathway, with the consequent production of cytokines within the central nervous system, may be involved in the mediation of a number of phenomena that occur during cancer and cancer treatment. (C) 2003 Elsevier Science (USA). All rights reserved.