Transcranial cytokine gradients in patients requiring intensive care after acute brain injury.

After acute brain injury there may be increased intracranial production of cytokines, with activation of inflammatory cascades. We have sought to determine if a transcranial cytokine gradient was demonstrable in paired sera of 32 patients requiring intensive care after acute brain injury. The difference between concentrations of IL-1 beta, IL-6, IL-8 and TNF alpha in jugular venous and arterial serum was measured on admission, and at 24, 48 and 96 h after the primary injury. There were no differences in IL-1 beta, IL-8 or TNF alpha, but median gradients of 6.7 and 11.5 pg ml-1 for IL-6 were demonstrated in the traumatic brain injury (n = 22) and subarachnoid haemorrhage (n = 10) groups, respectively (normal values in serum < 4.7 pg ml-1; P < 0.001 both groups). This suggests that there is significant production of IL-6 by intracranial cells after acute brain injury. Therapy directed towards combatting the negative effects of IL-6 may potentially benefit patients who have sustained an acute brain injury.