Measles antigen in multiple sclerosis: Identification in the jejunum by immunofluorescence

Measles virus antigen has been detected by the fluorescent antibody method in jejunal mucosa obtained from 24 patients with clinical multiple sclerosis. Deposits of antigen, various components of the complement system and on occasion immunoglobulins were identified in the epithelial basement membrane. Antigen and complement were usually found in the lamina propria, and sometimes could be seen within epithelial cells and in capillary walls. These findings support the concept that multiple sclerosis is caused by persistent measles infection, and indicate that the virus is harbored in the wall of the small intestine.