Interleukin-2 levels in serum and cerebrospinal fluid of multiple sclerosis patients.

A sensitive enzyme-linked immunosorbent assay method was employed to measure interleukin-2 (IL-2) levels in cerebrospinal fluid (CSF) and sera from 30 patients with multiple sclerosis (MS) and 8 patients with other neurological diseases. Detectable levels of IL-2 were found in 6 sera and 9 CSF samples of 21 patients with acute relapse of MS. However, only 3 patients showed measurable IL-2 both in CSF and in serum. IL-2 was not detected in specimens from 9 patients with chronic-progressive MS, whereas high levels were found in 2 CSF samples from patients with aseptic meningitis. Our data suggest that systemic activation of a T-cell population is present in some MS patients; moreover, an active immune mechanism involving IL-2 production takes place within the central nervous system.