25-hydroxyvitamin D in cerebrospinal fluid during relapse and remission of multiple sclerosis.

Hypovitaminosis D may play a role in multiple sclerosis (MS), but little is known about intrathecal vitamin D. 25-Hydroxyvitamin D was measured in cerebrospinal fluid and sera from 36 patients with relapsing-remitting MS, 20 patients with other inflammatory neurological diseases and 18 patients with non-inflammatory neurological diseases with liquid chromatography-mass spectrometry. There were no significant differences in cerebrospinal fluid concentrations of 25-hydroxyvitamin D, but the cerebrospinal fluid:serum ratio was significantly lower in MS compared with other inflammatory neurological diseases (p=0.0012) and non-inflammatory neurological diseases (p=0.041) patients. The concentrations of 25-hydroxyvitamin D in cerebrospinal fluid and serum were positively correlated and their ratio was similar to that of albumin. Neither the concentrations of 25-hydroxyvitamin D in cerebrospinal fluid or serum nor their ratio were associated with the presence of relapses or gadolinium-enhanced lesions. These results do not support that 25-hydroxyvitamin D is actively transported to the cerebrospinal fluid, or that the cerebrospinal fluid or serum levels or their ratio exert a major impact on MS activity.