Physiological levels of pro- and anti-inflammatory mediators in cerebrospinal fluid and plasma: a normative study

Numerous recent studies have reported a significant inflammatory reaction in the brain and the systemic circulation following traumatic brain injury (TBI), infection, or neoplasm of the brain with a sequential release of pro- and anti-inflammatory mediators. Although there is growing knowledge and understanding of the mechanisms leading to the often poor outcome of these patients, only a limited database exists on the physiological expression of pro- and anti-inflammatory cytokines and molecules in plasma and particularly in cerebrospinal fluid (CSF). Therefore, we analyzed paired plasma/CSF samples of healthy human volunteers for the physiological concentrations of Interleukin (IL)-6, IL-8, IL-10, soluble TNF-receptors (sTNF-R) p55 and p75, soluble ICAM (sICAM), and soluble E-selectin (sE-selectin). A physiological release of IL-6, IL-8, IL-10, and sTNF-R p55 and p75 was detected in plasma and CSF. In contrast, sICAM and sE-selectin were only detectable in plasma. Pro- and anti-inflammatory mediators exhibited different concentration patterns in plasma and CSF, suggesting a pro-inflammatory predisposition in the central nervous system.