Interleukin-1 beta and interleukin-1 receptor antagonist levels in cerebrospinal fluid of aseptic meningitis patients.

The inflammatory process in aseptic meningitis is generally mild and self-limited. To evaluate control mechanisms underlying this process, we determined interleukin (IL)-1 beta and IL-1 receptor antagonist (IL-1ra) concentrations, using enzyme linked immunosorbent assay, in cerebrospinal fluid from patients with aseptic meningitis (n = 55, median age [range]; 5.0 [1-15] years). We cross-sectionally analyzed the relationship of IL-1 beta and IL-1ra levels to leucocyte count in terms of interval between clinical onset and lumbar puncture. IL-1 beta levels were highest in the cerebrospinal fluid obtained between 12 and 24 hours after onset (n = 23, median: 2.30 pg/ml). The IL-1 beta level was significantly correlated with leucocyte count. On the other hand, IL-1ra level tended to increase over a longer interval, reaching a plateau between 24 and 36 hours after onset (n = 13, median: 5190 pg/ml). The molar ratio of IL-1ra to IL-1 beta was thus lowest between 12 and 24 hours after onset (median: 2341), which coincided with the peak increase in leucocyte count. The results are compatible with the idea that IL-1ra should be important for the regulation of IL-1 beta activity associated with leucocyte migration in aseptic meningitis.