DIFFERENT RELEASE OF CYTOKINES INTO THE CEREBROSPINAL-FLUID FOLLOWINGSURGERY FOR INTRAAXIAL AND EXTRAAXIAL BRAIN-TUMORS

To elucidate the role of cytokines in brain repair processes and in lo cal inflammation after neurosurgical procedures, cerebrospinal fluid ( CSF) samples from 8 patients with intra-axial tumours and 8 patients w ith extra-axial tumours were analysed for interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1ra), IL-6, IL-8, IL-10, and tumour necrosis factor (TNF)-alpha at the beginning and after surgery. Levels of IL-6 and IL-8 increased dramatically in all patients just hours after surge ry and fell during subsequent days. IL-1beta was found only in low amo unts in the CSF of both patient groups. Other cytokines demonstrated d ifferent courses. In patients with intra-axial rumours IL-1ra peaked t wo to four hours after surgery with a subsequent decrease. In patients with extra-axial rumours there was a continuous low-level IL-1ra rele ase into the CSF without a peak. TNF-alpha was not present in detectab le levels in the CSF after surgery for extra-axial rumours but was fou nd to peak two to four hours after surgery for intra-axial rumours. IL -10 was detected in the CSF of both patient groups, bur a higher peak was seen after surgery for extra-axial rumours. These results suggest different requirements for the cytokine response and an involvement of different cell types in cytokine release. However, the analysis of th e CSF from both patient groups showed no differences in cell counts an d populations, with a mild pleocytosis bring present in both patient g roups after surgery. Therefore, we conclude that after surgery for ext ra-axial rumours cytokines were predominately produced by non-immune c ells stimulated through hypoxia or mechanical irritation. After surger y for intra-axial tumours with a significant brain injury immune cells - activated by necrotic material - seem to be involved in the process of cytokine synthesis. In these cases an additional IL-1ra and TNF-al pha peak was found and these cytokines may be markers for cerebral inj ury.