Substances which modulate leukocyte migration are present in CSF during meningitis.

We studied the effects on in vitro leukocyte migration of cerebrospinal fluid from 14 patients with and 7 patients without meningitis. Meningitic CSF, but not control CSF, contained activity that was chemotactic for peripheral blood leukocytes. In an unusual case of staphylococcal meningitis associated with a blunted CSF pleocytosis and a poor clinical response to antibiotics, an inhibitor of leukocyte chemotaxis was identified in the CSF. This inhibitor may have diminished local leukocyte accumulation in vivo and thereby adversely affected host defense mechanisms and clinical outcome. No inhibitors were found in other CSF samples tested. Soluble mediators present in CSF may modulate the local accumulation of leukocytes and therefore affect host defenses in meningitis.