S-100 beta reflects the extent of injury and outcome, whereas neuronal specific enolase is a better indicator of neuroinflammation in patients with severe traumatic brain injury

It has been hypothesized that immunoactivation may contribute to brain dama ge and affect outcome after traumatic brain injury (TBI). In order to deter mine the role of inflammation after TBI, we studied the interrelationship o f the immune mediators sICAM-1 and IL-6 with the levels of S-100 beta and n euronal specific enolase (NSE), both recognized markers of brain damage. In addition, the extent and type of cerebral injury and the neurological outc ome were related to these measured markers of injury. An evident elevation of S-100 beta (range of means: 2.7-81.4 ng/mL) and NSE (range of means: 2.0 -81.3 ng/mL) was observed in CSF of all 13 patients during the first 3 post traumatic days and decreased over 2 weeks. In parallel, the production of s ICAM-1 (range of means: 0.7-11.9 ng/mL) and IL-6 (range of means: 0.1-8.2 n g/mL) was also markedly enhanced in CSF. The CSF means of S-100 beta and NS E per patient correlated with IL-6 (r = 0.60, p < 0.05; and r = 0.64, p < 0 .05, respectively), whereas the corresponding means in serum showed a signi ficant correlation only between NSE and IL-6 (r = 0.56, p < 0.05), Maximal CSF values of NSE and sICAM-1 Correlated with each other (r = 0.57, p < 0.0 5). The contusion sizes assessed on the CT scans correlated with the means of S-100 beta (r = 0.63, p < 0.05) and NSE (r = 0.71,p < 0.05) in CSF and w ith the mean of S-100 beta in serum, although not statistically significant (r = 0.52, p = 0.06), hut not with serum NSE, Interestingly, linear regres sion analysis demonstrated that means of S-100 beta in CSF (r = 0.78, p = 0 .002) and serum (r = 0.82, p < 0.001) correlated with the GOS, These result s indicate that the elevation of these parameters in CSF depends on the ext ent of injury and that S-100<beta> may be a predictor of outcome after TBI, whereas NSE reflects better the inflammatory response.