We investigated neuropsychiatric patients with non-bacterial meningitis (N-MEN)), assumed chronic low level neuroinflammation (schizophrenic SCH-S and affective spectrum disorders PSYCH-A) and tension headache (CEPH). Cytokines investigated were IL-1beta, IL-2, IL-8/CXCL8, the antiinflammatory IL-10 and IL-17.

to differentiate chronic and acute neuropsychiatric diseases by cytokine profiles and to evaluate cytokine levels in the CSF and peripheral blood to characterize the two compartments

Included were 10 N-MEN, 10 CEPH, 15 PSYCH-A and 16 PSYCH-S patients. Peripheral blood and CSF was taken in parallel. Measurement on a commercial multiplex immunoassayplatform (Mesoscale) by a modified protocol. Statistics: Mann-Whitney-U-Test and Kruskal-Wallis H-Test.

Highest levels of IL1b, IL-2, IL-8 and IL-17 were observed in the CSF of N-MEN, whereas in serum, levels were not or slightly elevated. Significant (p< 0.05) tested in CSF for N-MEM versus CEPH,PSYCH-A,PSYCH-S for IL-8 and versus PSYCH-A,PSYCH-S for IL-17. IL-10 CSF levels were also highest in N-MEM, and significant also versus CEPH,PSYCH-A,PSYCH-S, but IL-10 in serum was even higher than in CSF. We observed in all cytokine (except IL-2) significant differences either in serum or in CSF or both between the diseases; but more frequent CSF than in the serum.

N-MEN patients displayed highest ratios of CSF to serum levels for all cytokines (mean between 1.6 and 63).

Investigation of cytokines in CSF is more sensitive than in serum to detect differences between neuropsychiatric diseases. Cytokine patterns are disease specific. Elevated IL-1beta, IL-2 and IL-8 CSF/serum ratios in N-MEM may indicate an intrathecal synthesis of cytokines.