Cerebrospinal fluid levels of IL-6 in patients with acute infections of the central nervous system.

Interleukin-6 (IL-6) activity was measured in the cerebrospinal fluid (CSF) of patients with acute bacterial or viral meningitis and in AIDS patients with various cerebral disorders. Increased levels of IL-6 were detected in the CSF of patients with bacterial meningitis. On the contrary, most of the samples from patients with viral meningitis (predominantly caused by mumps virus) had no detectable IL-6 activity in CSF. A moderate increase of IL-6 levels was detected in the CSF of AIDS patients with AIDS dementia complex (ADC), progressive multifocal leukoencephalopathy and cerebral toxoplasmosis. Moreover, higher levels of IL-6 were detected in the CSF of patients with cryptococcal meningitis. We conclude that the initial events of CSF inflammation in patients with acute viral meningitis are different from those in patients with acute bacterial meningitis, and the role of IL-6 is less critical to the process.