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 havemore active immune responses than those in healthy subjects. The ability of DC as antigen-presenting cell is determined by its maturity level. InGD, 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 immunoregulatoryeffects of vitamin D, mainly through inhibition of DC maturation, which may decrease the DC's immunogenic profile. This study aims to identify theeffect 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 wascultured, with or without 1,25-D3 in vitro at monocytic phase. The DC maturation was then stimulated by lipopolysaccharide (LPS) and evaluatedbased on the expression of DC markers (human leukocyte antigen-D-related [HLA-DR], CD80, CD40, CD83, CD14, and CD206) and the ratio of cytokineinterleukin-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 ofCD14 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.Keywords: Vitamin D, Graves' disease, Dendritic cells