Myelin basic protein in CSF and blood. Relationship between its presence and the occurrence of a destructive process in the brains of encephalitic patients.

Serum and CSF levels of myelin basic protein (MBP) were measured in 50 patients with encephalitis of various origins and severity. In nearly 50%, the CSF samples were found to display immunoreactivity of MBP. Positivity was found to be correlated with the severity of the clinical signs. More precisely, it corresponded to cases with suspected extensive brain destruction. No relationship could be observed with the cause of disease. Positive tests of sera were infrequent, even from patients whose CSF was rich in MBP. Longitudinal studies performed on 20 patients who were serially investigated during periods ranging from three weeks to 18 months demonstrated that after an attack, MBP liberation into the CSF persists for one to three weeks. The MBP assay should serve as an index for destruction of nervous tissue.