25-Hydroxyvitamin D serum level in Hashimoto’s thyroiditis, but not Graves’ disease is relatively deficient Abstract. Vitamin D is a modulator of both the innate and adaptive immune system. As vitamin D deficiency was a risk factor for some autoimmune diseases, we aimed to evaluate the serum vitamin D levels in autoimmune thyroid diseases(AITD) including Graves’ disease (GD)...