Cellular and humoral responses to myelin basic protein in multiple sclerosis: a dichotomy.

The macrophage migration inhibition factor (MIF) assay and a counterimmunodiffusion assay were utilized to measure immune responses to human myelin basic protein in 75 patients with multiple sclerosis (MS) and in 120 control subjects. Eight out of ten MS patients in acute exacerbation and one out of seventeen convalescent, but none of chronically ill MS patients gave positive results in the MIF test. Forty-six percent of the patients with negative MIF assays but only 22% of those with positive assays had positive antibody results. In the counterimmunodiffusion assay, myelin basic protein antibody was demonstrated in almost 2/3 of patients during convalescence but it was not present in those whose illness had been stable for 6 months or longer. While no correlation with the stage or duration of the illness was present in other disorders, in MS an inverse correlation with clinical activity and in vitro evidence of cellular sensitization to encephalitogenic basic protein was apparent.