Discordant temporal patterns of S100 β and cleaved tau protein elevation after head injury: a pilot study

There is considerable interest in S100 g protein as a potential marker that can be used to quantify central nervous system injury. However, increasing appreciation that S100 g may be produced by non-neural tissue (specifically adipocytes), has led to a search for more specific markers of brain injury. Recent interests have focused on a cleaved form of tau protein (c τ P) which is elevated in CSF from patients suffering traumatic brain injury. We have investigated whether levels in peripheral blood are a satisfactory alternative to provide an accessible marker of CNS injury severity. We measured levels of S100 g and c τ P in arterial blood from 20 patients with severe head injury. When compared with normal values S100 g was elevated 10-fold in the first 24 hours and c τ P was elevated at all time points, but showed a reversal of the temporal trend observed with S100 g. Patients with a poor outcome (GOS 1-3) had significantly higher S100 g levels on day one. Plasma c τ P levels did not correlate with outcome following head injury.