Determination of interleukin-2 (IL-2) and soluble IL-2 receptors (S-IL-2R) in serum and cerebrospinal fluid does not discriminate between purulent and aseptic meningitis

Elevated levels of soluble interleukin-2 receptors (S-IL-2R) but not interleukin-2 (IL-2) activity were found in sera from patients with aseptic meningitis, purulent meningitis, and meningism. Elevated levels of S-IL-2R in serum was also observed in 4/4 patients with bacterial pneumonia and 2/2 patients with infectious mononucleosis. The inflammation of the meninges was only reflected by an increase in S-IL-2R in cerebrospinal fluid (CSF) in 1/14 patients with aseptic meningitis and 3/10 patients with purulent meningitis. Further, IL-2 activity was only demonstrated in CSF from 2 patients with aseptic meningitis and 3 patients with purulent meningitis. In conclusion, neither S-IL-2R nor IL-2 in serum or CSF seems to have any value in the diagnosis of or discrimination between purulent meningitis and aseptic meningitis. Further, the elevation of S-IL-2R in serum is not specific for infections primarily fought by cytotoxic T-lymphocytes such as viral infections, but seems merely to reflect an unspecific activation of the immune system.