What do People with Primary Systemic Vasculitis want to know about their illness

FoxP3 þ frequencies. By contrast, in the absence of DCs, 25(OH)D3 caused modest CTLA-4 induction and IFNsuppression (P < 0.05 for all). These differences corresponded with CYP27B1 levels, as maturation induced much higher CYP27B1 in DCs than arose in T cells (P < 0.05). CTLA-4 blockade overcame 1,25(OH)2D3- mediated suppression of T cell division in DC stimulations and prevented down-regulation of co-stimulatory CD80 and CD86 on DCs. PB T cells from synovitis patients responded normally to 1,25(OH)2D3 with suppressed IL-17 and IFN� (P < 0.0001). 1,25(OH)2D3 also reduced SF IL-17 (P < 0.05) but not IFN� . Conclusions: We have shown that DCs can efficiently convert 25(OH)D3 to drive 1,25(OH)2D3-modified T cell responses and that up-regulation of CTLA-4 is mechanistically important in immune suppression by vitamin D. Thus, 25(OH)D3 supplement could be useful in the treatment of conditions such as RA. This is supported by our finding that T cells from synovitis patients can respond to 1,25(OH)2D3. Disclosure statement: The authors have declared no conflicts of interest.