The use of cytokine and C-reactive protein measurements in cerebrospinal fluid during acute infective meningitis.

Cerebrospinal fluid (CSF) concentrations of C-reactive protein (CRP), tumour necrosis factor alpha (TNF), interleukin-6 (IL-6), total protein (TP) and white cell count with differential (WCC) have been measured in 24 patients presenting with acute bacterial or viral meningitis and also in a non-infected, non-inflamed control group (n = 24). In acute viral meningitis, CRP levels were not raised when compared to controls and there was a discordance between high levels of the primary inflammatory mediators (IL-6 and TNF) and the low measured CRP levels. CRP levels were raised in cases of bacterial meningitis. A concentration of 100 ng/mL CRP had a sensitivity of 87% for bacterial meningitis. TNF concentrations in the CSF were significantly raised in cases of acute bacterial meningitis (P < 0.001). Smaller but variable elevations were seen in the patients with acute viral meningitis. One patient, who succumbed to bacterial infection, showed low CSF levels of CRP, TNF and WCC but an elevated IL-6 concentration. Another, presenting with low CSF WCC, had raised concentrations of CRP, TNF and IL-6 which pointed to the correct diagnosis of acute bacterial meningitis. The development of methods yielding rapid analysis for these cytokines together with a sensitive assay for CRP in CSF would be a useful adjunct to conventional investigation.