CSF neopterin as marker of disease activity in multiple sclerosis.

Levels of neopterin, a factor known to be released from macrophages and monocytes at increased rates in cellular immune reactions, were higher in cerebrospinal fluid (CSF) in 10 of 12 patients with multiple sclerosis (MS) during exacerbations in comparison with remissions. This significant elevation in CSF during exacerbations was not reflected in serum. These results indicate that determination of neopterin in CSF may be a useful marker of disease activity in MS.