Intrathecal synthesis of antibodies to diphtheria and tetanus toxoids in multiple sclerosis patients.

Antibodies to diphtheria and tetanus toxoids were measured in 30 multiple sclerosis (MS) patients and 30 neurological control patients by enzyme-immunoassays. The frequency of antibody-positive patients and the titer distribution were similar in both groups. In spite of this, some MS patients had intrathecal antibody synthesis to these toxoids. The histories of these patents did not reveal any diseases caused by diphtheria of tetanus bacteria but they had been vaccinated 2-24 years before the first clinical symptoms of MS. The findings suggest that lymphocytes earlier committed to specific antibody synthesis outside the brain compartment could enter the brain before or after the clinical onset of MS.