Vitamin D3 supplementation and the IL-2/IL-2R pathway in multiple sclerosis: Attenuation of progressive disturbances?

Vitamin D3 upregulates IL-2 receptor alpha (IL2RA, CD25)-expression on CD4+ T cells in vitro. We investigated effects of 48-weeks vitamin D3 supplements on CD25-expression by CD4+ T cells of patients with multiple sclerosis (MS). There was no significant difference between the vitamin D3 (n=30) and placebo group (n=23) in IL2RA mRNA-expression by PBMC. Likewise, CD25 cell surface-expression by conventional or regulatory T cells (Treg) did not differ between groups, although Treg CD25-expression and circulating soluble-CD25 levels decreased significantly in the placebo but not vitamin D3-group. We speculate that vitamin D3 may promote the maintenance of CD25-related immune homeostasis in MS.