Intensive immunosuppression in patients with disseminated sclerosis. III. Lymphocyte response in vitro.

Lymphocytes from fifteen multiple sclerosis patients gave responses to phytohaemagglutinin (PHA), conconavalin A (con A) and pokeweed mitogen (PWM) which were in the normal range. However, the responses of lymphocytes to stimulation by an allogeneic lymphoid cell line (LCL) were significantly lower in HLA-7-positive than in HLA-7-negative patients (a distinction not found in control groups). Depression of con A, PHA and PWM responses were observed during intensive immunosuppression. Responses to LCL were unaltered or increased during initial azathioprine and prednisone treatment. The depression of this response following antilymphocyte globulin (ALG) treatment was delayed in the HLA-7-positive patients. One week after the end of ALG treatment, most PHA, con A and PWM responses had returned to low normal values. Reduction of azathioprine and prednisone treatment at the end of 1 year resulted in a sharp rise in PHA and con A responses in some patients. Relapses in patients were frequently associated with low responses to LCL cells.