Lymphocyte populations in the cerebrospinal fluid and peripheral blood of patients with multiple sclerosis and optic neuritis.

The cerebrospinal fluid (CSF) and peripheral blood (PB) of patients with multiple sclerosis (MS), optic neuritis (ON), and aseptic meningitis (AM) were studied with respect to the percentage of B cells (using membrane Ig fluorescence), T cells, and T-cell subpopulations (using a rosetting technique or monoclonal antibodies). In the PB of all three patient groups there were normal B-cell levels but a significant decrease in T cells compared with PB of normal individuals. In the CSF the B cells were reduced but the T cells elevated when compared with the PB of the patients, and these differences were statistically significant. The level of total T cells was not influenced by disease activity in MS or ON, but there was a significant reduction of suppressor cells in PB during disease activity in MS patients. In CSF there were also fewer suppressor cells during active disease, but the reduction was not statistically significant. Differences in B and T cells in CSF and PB indicate that the immune reactions within the central nervous system are at least partially isolated from the rest of the immune system. The changes in the T-cell subpopulations in MS support the evidence for an immunoregulatory defect in this disease.