Lymphocyte subpopulations in multiple sclerosis: spontaneous and mitogen-induced activity.

Lymphocytes of chronic progressive multiple sclerosis (MS) patients and healthy persons were isolated by nylon-wool column filtration followed by density centrifugation. Incubating part of these lymphocytes with 2- aminoethyliso thiouronium bromide hydrobromide-treated sheep erythrocytes resulted in two other subfractions, the rosette-forming (E+) lymphocytes and the nonrosette -forming (E-) lymphocytes. Increased spontaneous activity was observed with the nonfractionated lymphocyte populations and with the E+- and E- -cell fractions of MS patients compared to the corresponding cell populations of controls following a culture period of one or several days. Phytohemagglutinin- and pokeweed mitogen-induced stimulation of these different lymphocyte fractions was the same in MS patients and controls. No influence of disease activity could be found on the immune parameters. Characterization of the different lymphocyte populations with monoclonal anti-human T-cell antibodies demonstrated a prevalence for helper T cells in forming rosettes.