Interleukin-6 and its soluble receptor in serum and cerebrospinal fluid after cerebral trauma

Interleukin-6 (IL-6) and its soluble receptor (sIL-6-R) were measured in cerebrospinal fluid (CSF) and serum of 11 severely head injured patients for up to 3 weeks following trauma. IL-6 increased immediately after injury displaying much higher concentrations in CSF than in serum (n = 11). Differently, median levels of sIL-6-R remained in the normal ranges being 10 times higher in serum than in CSF. However, increased amounts over control levels were found in CSF (n = 7) and intrathecal release of sIL-6-R was also suggested (n = 7). Although no correlation with the extent of cerebral lesion or with clinical outcome was evident, elevation of sIL-6-R in CSF supports a pivotal role for IL-6/sIL-6-R complex in the injured brain.