Serum measles antibodies in multiple sclerosis.

Serum haemagglutination inhibition/HI/antibody titres to measles virus were examined in 80 multiple sclerosis patients, their 20 sibs, in 990 healthy controls, and 25 control patients. The measles HI titres were significantly raised in the serum of multiple sclerosis patients compared with healthy controls. There was no statistical difference between the levels of HI antibody titres in multiple sclerosis patients and their sibs. The measles HI titres decreased significantly in older age groups of healthy controls, whereas an analogous drop was not found in the multiple sclerosis group. The levels of serum HI antibody titres did not correlate with the sex of patients with multiple sclerosis or the activity of the disease. In the CSF of six multiple sclerosis patients low titres of HI antibodies were detected, whereas none of eight control patients had measurable traces of measles antibodies in the CSF. The significance of these findings in the aetiology of multiple sclerosis is briefly discussed.