Myelin basic protein and S-100 antigen in cerebrospinal fluid of patients with multiple sclerosis in the acute phase.

It has previously been demonstrated that both Myelin Basic Protein (MBP) and S-100 are released in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients during acute phases of exacerbation of the disease. In order to investigate the pathobiological significance of the release of these two proteins into the CSF, MBP and S-100 were assayed in 10 MS patients during the five weeks following onset of an acute exacerbation. MBP was detectable in CSF during the first three weeks after exacerbation, while S-100 was detectable during the entire period of observation, at least in some of the patients. MBP reached its highest CSF concentrations during the first two weeks while S-100 did so in the third week, decreasing thereafter. This difference in time of presence of MBP and S-100 in the CSF is probably due to the different biological origin, MBP being a marker of myelin sheath injury, and S-100, more probably, of astrocytic activity.