Meningitis is accompanied by a differential immigration of leukocytes into the subarachnoid space. Since the mechanisms regulating leukocyte invasion are still incompletely understood, we studied the release of the neutrophil-attracting alpha-chemokines IL-8 and GRO-alpha and the mononuclear cell-attracting beta-chemokines MCP-1, MIP-1alpha, and RANTES during meningitis. In 48 paired CSF and serum samples from patients hospitalized for meningitic symptoms, high levels of IL-8, GRO-alpha, and MCP-1 were detected in the CSF during bacterial and abacterial meningitis. Elevated chemokine levels were not found in the blood serum samples taken in parallel. The release of MIP-1alpha or RANTES was below detection limits. The IL-8 and GRO-alpha levels significantly correlated with the number of immigrated granulocytes in the CSF of patients with bacterial meningitis. A similar correlation was found when MCP-1 levels and the mononuclear cell count were analyzed in abacterial meningitis. These findings suggest that the local production of the alpha-chemokines IL-8 and GRO-alpha and of the beta-chemokine MCP-1 represents the major chemoattractant stimulus for the differential recruitment of leukocytes into the subarachnoid space during meningitis.