"Topically applied 1,25(OH)(2)D(3) reduces the number of dendritic cells in the skin, resulting in suppressed immunity and in particular reduced contact hypersensitivity (CHS) responses."
.........is taken out of context and does not apply to the general and alleged immunosuppressive qualities that you claim D3 has on the overall Immune System .
This only applies to the topical (external) application of D3 for those who have hypersensitivity in the outer epithelial layers of the skin to UVB rays.
D3 acts by suppression of the immune response in the skin to this hypersensitivity, and NOT the Immune System generally.