Adhesion molecule expression on cerebrospinal fluid T lymphocytes: Evidence for common recruitment mechanisms in multiple sclerosis, aseptic meningitis, and normal controls

Abstract

The expression of T‐cell surface antigens was investigated in the cerebrospinal fluid (CSF) and peripheral blood of 11 patients with multiple sclerosis, 6 patients with aseptic meningitis, and 16 healthy subjects. A panel of monoclonal antibodies to adhesion and activation proteins was used in combination with an anti‐CD3 antibody in dual‐color flow cytometry. The problem of low cell numbers in the CSF from normal individuals was overcome by use of a modified staining procedure in microtiter plates, enabling analysis of as few as 5,000 cells. The majority of T cells in the CSF of the three patient groups exhibited the phenotype of memory cells (CD45RO⁺). CSF T cells also expressed significantly higher levels of several adhesion and activation molecules, including very late activation (VLA) antigens 3 through 6, lymphocyte function‐associated (LFA) antigen 1, LFA‐3, CD2, CD26, and CD44. Comparison between the different categories revealed that peripheral blood T cells from patients with multiple sclerosis expressed significantly lower amounts of the VLA integrins 4 and 5 as well as their common β subunit CD29, compared with normal control subjects. No differences between patients with multiple sclerosis and control subjects could, however, be seen regarding the distribution of memory/naive cells or CD4⁺/CD8⁺ cells in peripheral blood. Our data support a hypothesis that memory T cells with a high expression of several adhesion molecules are selectively recruited to the central nervous system compartment, under both pathological and normal conditions. We also provide evidence for an altered expression of adhesion molecules on peripheral blood T cells in patients with multiple sclerosis that is independent of the memory cell phenotype as defined by the expression of the CD45RO epitope.