Dietary Vitamin D Increases Percentages and Function of Regulatory T Cells in the Skin-Draining Lymph Nodes and Suppresses Dermal Inflammation

Skin inflammatory responses in individuals with allergic dermatitis may be suppressed by dietary vitamin d through induction and upregulation of the suppressive activity of regulatory t (t r e g) cells. vitamin d may also promote t r e g cell tropism to dermal sites. in the current study,we examined the capacity of dietary vitamin d3 to modulate skin inflammation and the numbers and activity of t r e g cells in skin and other sites including lungs,spleen,and blood. in female balb/c mice,dietary vitamin d3 suppressed the effector phase of a biphasic ear swelling response induced by dinitrofluorobenzene in comparison vitamin d3-deficient female balb/c mice. vitamin d3 increased the percentage of t r e g (cd3+cd4+cd25+foxp3+) cells in the skin-draining lymph nodes (sdln). the suppressive activity of t r e g cells in the sdln,mesenteric lymph nodes,spleen,and blood was upregulated by vitamin d3. however,there was no difference in the expression of the naturally occurring t r e g cell marker,neuropilin,nor the expression of ccr4 or ccr10 (skin-tropic chemokine receptors) on t r e g cells in skin,sdln,lungs,and airway-draining lymph nodes. these data suggest that dietary vitamin d3 increased the percentages and suppressive activity of t r e g cells in the sdln,which are poised to suppress dermal inflammation. � 2016 shelley gorman et al.