Central memory CD4+ T cells dominate the normal cerebrospinal fluid

Abstract

Background: To use cerebrospinal fluid (CSF) immune phenotyping as a diagnostic and research tool, we have set out to establish reference values of white blood cell (WBC) subsets in CSF. Methods: We assessed the absolute numbers and percentages of WBC subsets by 6-color flow cytometry in paired CSF and blood samples of 84 individuals without neurological disease who underwent spinal anaesthesia for surgery. Leukocyte (i.e., lymphocytes, granulocytes, and monocytes), lymphocyte (i.e., T [CD4⁺ and CD8⁺], NK, NKT and B cells), T cell (i.e., naïve, central memory, effector memory, and regulatory) and dendritic cell subsets (i.e., myeloid and plasmacytoid) were studied. Results: CSF showed a predominance of T cells, while granulocytes, B and NK cells were relatively rare compared to blood. The majority of T cells in CSF consisted of CD4⁺ T cells (∼70%), most of them (∼90%) with a central memory phenotype, while B cells were almost absent (+ T cells, mainly with a central memory phenotype, and the presence of dendritic cells in CSF suggests an active adaptive immune response under normal conditions in the central nervous system (CNS). © 2010 International Clinical Cytometry Society