Retinol measurements and retinoid receptor gene expression in patients with multiple sclerosis

Treatment with interferon (IFN)-beta1a has been associated with decreased disease activity in patients with multiple sclerosis (MS). In several biological systems, type 1 IFNs and retinoids have been demonstrated to have synergistic effects. In these studies, we measured blood and cerebrospinal fluid (CSF) retinol levels and naïve and memory T-helper cell subset percentages in samples from a group of patients with MS. We also examined retinol receptor expression in peripheral blood cells from MS patients with or without a history of prior treatment with IFN-beta1a. The mean plasma retinol level for untreated relapsing-remitting (RR) MS patients was lower than for patients with noninflammatory neurological disease. Among IFN-beta1a-treated RR patients, mean levels were slightly higher than for RR patients not on treatment Lower plasma retinol levels among the MS patents studied were associated with higher CSF retinol index measurements--a measure that was calculated to correct for nonspecific leakage of retinol from blood into CSF. Far the MS samples examined, there was a borderline statstically significant direct correlation between CSF retinol index measurements and CSF memory T-helper cell percentages. Examination of peripheral blood from untreated RR patents for retinoid receptor mRNA expression revealed the expression of the retinoic add receptor (RAR)-alpha, RAR-gamma, and retinoic X receptor (RXR)-alpha receptor subtypes. For RR patients on IFN-beta1a therapy, expression of the some RAR subtypes was noted as well as expression of RXR-beta and RXR-gamma. These studies suggest an association between plasma retinol levels and clincal disease activity in patents with MS and that treatment with IFN-beta1a may be associated with activation of specific retnoid receptor subtypes.