Acute exacerbation of multiple sclerosis increases plasma levels of S-100 protein

Objectives - To determine whether an increase in plasma concentration of S-100 protein can serve as a marker for acute exacerbation of multiple sclerosis. Material and methods - The plasma level of S-100 protein was investigated in 28 patients suffering from multiple sclerosis. Of these, 17 patients were admitted for acute exacerbation and 11 patients had a stable disease with no clinical signs for acute exacerbation. S-100 protein concentrations in plasma were determined with an immunofluorometric sandwich assay. Results - Plasma concentrations were significantly elevated in patients who were examined within 7 days after the onset of acute exacerbation ( n =6). S-100 levels of patients 8 to 28 days after the onset of acute exacerbation ( n =11) did not differ from healthy controls ( n =120). Eleven patients with multiple sclerosis without acute exacerbation had moderately elevated plasma levels. Conclusion - The plasma concentration of S-100 protein is a sensitive although unspecific indicator of neuronal damage and may be of use as a marker of disease activity in multiple sclerosis.