Local and systemic immune response in multiple sclerosis: analysis of CSF inflammatory changes and peripheral blood T-cell subsets.

In order to investigate the significance of the immune response in multiple sclerosis (MS), we have compared changes in peripheral blood T-cell subsets to the cellular and humoral responses in the cerebrospinal fluid. Using monoclonal antibodies defining the Leu-3a and Leu-2a phenotypes, we found a highly significant (2P less than 0.001) increase of the Leu-3a/Leu-2a cell ratio in peripheral blood T-cells of multiple sclerosis patients with disease activity (acute phase or progressive form), while patients with inactive disease did not differ from controls. No characteristic alterations in the CSF inflammatory response could be correlated with changes in T-cell subsets in the peripheral blood. There was no significant difference in the cerebrospinal fluid cell count or the mean IgG index between patients with high or low Leu-3a/Leu-2a cell ratios. We conclude that increased CSF IgG synthesis in MS is probably not a direct consequence of the apparent reduction of Leu-2a positive cells in the peripheral blood. Thus the biological significance of the change in immunoregulatory cells in the blood of multiple sclerosis patients remains unknown.