CSF lymphocyte subsets in aseptic meningitis: dual-labelling analysis with flow cytometry.

In order to characterize the CSF (cerebrospinal fluid) lymphocytes in CNS (central nervous system) inflammation, we examined paired samples of CSF and PB (peripheral blood) of 19 patients with acute aseptic meningitis, performing the dual labelling method on flow cytometry. Significantly higher percentages of CD3+ (T cell), CD4+ (helper-inducer), Leu3a+ Leu15- (cytotoxic-T) and HLA-DR+ CD3+ (activated-T) cells were identified in the CSF than in the PB of these patients. We observed significantly lower percentages of CD19+ (B cell), Leu2a+ Leu18+ (suppressor-inducer) and HLA-DR+ CD3- cells in the CSF than in the PB of these patients. Relative increases in helper-inducer, cytotoxic-T and activated-T cells in the CSF of aseptic meningitis are supposed to represent an active inflammatory process. However, whether these changes are specific or pathognomonic to any disease(s) remains to be solved.