Cerebrospinal fluid levels of myelin basic protein and creatin kinase BB as index of active demyelination.

Radioimmunoassay-determined myelin basic protein (MBP) shed to CSF during active demyelination, has been found to be a useful but non-specific test for MS. CSF creatin kinase BB (CK-BB), as measured by radioimmunoassay, is increased in a variety of neurological diseases, and has been considered a useful indication of brain damage but not of demyelinating diseases. Taking into account that the mean concentration of CSF CK-BB should not be increased in patients during the acute phase of MS, we suggest that the CSF MBP/CK-BB ratio could be a more specific index to demyelination than CSF-MBP alone. We also defined a laboratory demyelination pattern (CSF MBP greater than mean control MBP + 2 S.D. and CK-BB less than MBP). CSF levels of MBP and CSF levels of CK-BB were determined by radioimmunoassay in 232 patients with several neurological disorders and 33 control subjects. Patients diagnosed as having MS with clinical exacerbation had significantly higher values of CSF-MBP/CSF-BB ratio than control subjects. Our study showed a significant presence of demyelination pattern in CSF of patients with MS. We conclude that the CSF MBP/CK-BB ratio and the CSF demyelination pattern may be new and reliable tests for the diagnosis of MS.