An impaired vitamin D (vit-D) processing by immune cells of relapsing remitting multiple sclerosis (RRMS) patients may increase their vulnerability for a poor vit-D status. We assessed with qPCR the expression of vit-D related genes in PBMC and CD4(+) T-cells. Gene expression profiles of vit-D receptor (VDR), CYP27B1 and CYP24A1 did not differ between RRMS patients and healthy controls. Interestingly, more VDR expression in PBMC correlated with less circulating IFN-gamma(+) CD4(+) T-cells. Our results suggest that vit-D processing by immune cells is not impaired in RRMS, and is potentially relevant for the composition of the peripheral CD4(+) T-cell compartment. (C) 2011 Elsevier B.V. All rights reserved.