Effects of in vitro 1,25 Dihydroxyvitamin D on maturation of dendritic cells in Graves’ disease patients

Objective: The autoimmune reaction in Graves’ disease (GD) is induced by self-antigen, which is presented by dendritic cells (DCs). DCs in GD have more active immune responses than those in healthy subjects. The ability of DC as antigen-presenting cell is determined by its maturity level. In GD, vitamin D level is inversely proportional to antibody titer and proportionally associated with remission status. Studies on healthy subjects and autoimmune patients (systemic lupus erythematosus (SLE), multiple sclerosis (MS), and Crohn’s disease) have demonstrated immunoregulatory effects of vitamin D, mainly through inhibition of DC maturation, which may decrease the DC’s immunogenic profile. This study aims to identify the effect of 1,25-D3 in vitro on DC maturation in patients with GD. Methods: This is an experimental study, which was conducted in 12 GD patients with thyrotoxicosis. Monocyte-derived DC of GD patients was cultured, with or without 1,25-D3 in vitro at monocytic phase. The DC maturation was then stimulated by lipopolysaccharide (LPS) and evaluated based on the expression of DC markers (human leukocyte antigen-D-related [HLA-DR], CD80, CD40, CD83, CD14, and CD206) and the ratio of cytokine interleukin-12 (IL-12)/IL-10 levels in the supernatants. Results: Following the LPS stimulation, DC with 1,25-D3 showed lower expressions of HLA-DR, CD80, CD40, and CD83, and higher expressions of CD14 and CD206 compared to DC without 1,25-D3. DC with 1,25-D3 had lower ratio of IL-12/IL-10 levels than those without 1,25-D3. Conclusion: In vitro 1,25-D3 supplementation inhibits DC maturation in patients with GD.