Abstract
Seventy four patients with clinically definite multiple sclerosis were studied by using polyacrylamide gel electrophoresis of cerebrospinal fluid to assess blood-brain barrier function. Blood-brain barrier impairment was associated with recent clinical relapses of multiple sclerosis and worsened across a spectrum from the relapsing-remitting type of multiple sclerosis to secondary and primary progressive disease. The association between blood-brain barrier impairment and primary progressive disease is particularly interesting in the light of recent evidence that focal gadolinium enhancement on MRI is relatively unusual in patients with this disease.