Interleukin 6 in cerebrospinal fluid of patients with meningitis is not a useful diagnostic marker in the differential diagnosis of meningitis.

We assayed interleukin 6 (IL-6) concentrations in cerebrospinal fluid (CSF) from patients affected by meningitis of different aetiologies, and verified whether IL-6 can be used as a diagnostic marker in the differential diagnosis of meningitis. We used a monoclonal antibody enzyme immunoassay to test 98 CSF samples classified as pyogenic (15), viral (15), self-resolving aseptic meningitis (20), other infectious meningitis (9), neoplastic (4) and normal CSF from patients with (20) and without (15) non-infectious neurological diseases. CSF IL-6 concentrations were increased in pyogenic meningitis (100%) and in more than 50% of viral and other subarachnoid space infections, and rarely in patients without central nervous system infections. Though patients affected by pyogenic meningitis showed the highest levels of CSF IL-6, only a cut-off point > or = 10000 pg/mL was able to discriminate pyogenic meningitis from those of other aetiologies with a specificity > or = 94% and a positive predictive value of > or = 0.75 but the sensitivity was < or = 60%. Therefore, CSF IL-6 concentration is not a good diagnostic marker in the differential diagnosis of meningitis.

Interleukin-8 in cerebrospinal fluid from patients with meningitis of different etiologies: its possible role as neutrophil chemotactic factor.

Interleukin (IL)-8 concentrations were analyzed in 70 cerebrospinal fluid (CSF) samples from patients with meningitis of different etiologies and in 34 normal CSF samples. Patient groups included those with pyogenic meningitis, viral meningitis, self-resolving aseptic meningitis without a specific diagnosis, and meningitis of other etiologies and normal CSF from patients with and without neurologic disease. All samples from patients with pyogenic meningitis (18) but only 3 from patients with meningitis of other etiologies and with CSF polymorphonuclear leukocyte (PMNL) counts > or = 80% had IL-8 levels > or = 2.5 ng/mL. IL-8 was above the normal level (< or = 0.5 ng/mL) in samples from 5 of 13 viral and 8 of 23 self-resolving aseptic meningitis patients and in 7 of 13 samples from patients with meningitis caused by other microorganisms. There was a significant relationship between IL-8 levels and CSF PMNL counts in patients with nonpyogenic meningitis. The data suggest a possible role of IL-8 as PMNL chemotactic factor in different infections of the subarachnoid space, not only in pyogenic meningitis.