CSF and serum levels of soluble fractalkine (CX3CL1) in inflammatory diseases of the nervous system.

The new CX(3)C-chemokine fractalkine (CX(3)CL1) was measured by Western blot in the cerebrospinal fluid (CSF) and serum of patients with inflammatory diseases of the peripheral and central nervous system (Bell's palsy, BP; Guillain-Barré Syndrome, GBS; multiple sclerosis, MS; viral meningitis, VM; bacterial meningitis, BM) and patients with noninflammatory neurological diseases (controls). In controls, fractalkine was detectable at low concentrations in the CSF and, at much higher levels, in serum. In all inflammatory neurological diseases under study, CSF fractalkine levels were significantly (p<0.01) increased vs. controls (BM>>GBS>VM>MS>BP>controls). In serum, fractalkine levels were significantly increased only in MS patients. The fractalkine CSF/serum ratios (a measure of the chemotactic gradient) were significantly elevated in BM, VM and GBS; furthermore, they tended to be increased in BP and to be decreased in MS. The elevated fractalkine CSF/serum ratios in diseases without CSF pleocytosis (GBS, BP) and a lack of correlation between fractalkine levels and CSF leukocyte counts suggested that soluble fractalkine is not a major chemokine in the CSF. There was no evidence of significant intrathecal production of fractalkine as the mean fractalkine indices (fractalkine CSF/serum ratio:albumin CSF/serum ratio) were <1 in all inflammatory diseases and not significantly elevated vs. controls.