Decreased level of kynurenic acid in cerebrospinal fluid of relapsing-onset multiple sclerosis patients.

The present study was undertaken to measure cerebrospinal fluid (CSF) levels of kynurenic acid (KYNA) in patients with relapsing-onset multiple sclerosis (MS) during remission or not progressing for at least 2 months. In these patients the levels of CSF KYNA were found to be significantly lower compared with subjects with non-inflammatory neurological diseases, as well as those with inflammatory disease (median (interquartile range): 0.41 (0.3-0.5) pmol/ml, n=26 vs. 0.67 (0.5-1.1), n=23, P<0.01 and 1.7 (1.5-2.6), n=16, P<0.001, respectively). These results provide further evidence of the alterations in the kynurenine pathway during remitting-onset MS.