Neurobiology of interleukin-1 receptors: getting the message

Binding of the pro-inflammatory cytokine interleukin-l (IL-1) in the brain was first shown a decade ago [1], Interleukin-l receptors (LL-IR) in the br ain were, at that time, proposed to play a role in mediating symptoms of si ckness such as fever, activation of the hypothalamo-pituitary adrenal (HPA) -axis, behavioural depression and increased sleeping. Two years later, IL-1 immunoreactivity was shown in microglia of patients with Alzheimer's disea se [2]. Subsequent studies provided evidence for IL-1 expression in most ac ute and chronic CNS pathologies and gave rise to the concept that glial IL- 1 contributes to an inflammatory response in the brain. Recently, new membe rs of the IL-l receptor family have been discovered and roles for brain IL- 1 other than in inflammation are starting to emerge. During a recent meetin g* in Biarritz, leading experts in the field reflected on the accomplishmen ts and prospects in this rapidly expanding area of neurobiology.