Immunological Mechanisms Implicated in the Pathogenesis of Chronic Urticaria and Hashimoto Thyroiditis

Autoimmunity represents the attack of the immune system of an organism against its own cells and tissues. Autoimmune diseases may affect one organ (Hashimoto thyroiditis) or can be systemic (chronic urticaria). Many factors are implicated in the pathogenesis of autoimmunity (white cells, cytokines, chemokines). Hashimoto thyroiditis has been associated with chronic urticaria in the last 3 decades in a number of clinical studies. Antithyroid antibodies have been documented in a proportion ranging from 10% to 30% in chronic urticaria patients in different countries from 3 continents. Two of the factors involved in the mechanism of autoimmunity are present both in the pathophysiology of Hashimoto thyroiditis and chronic urticaria. According to recent studies, IL6 is implicated in the pathogenesis of both diseases. TregsCD(4+) CD25+ Foxp(3+) cells have also been implicated in the pathological mechanisms of these 2 entities. This review offers an explanation of the clinical and statistical association between these two diseases from the pathophysiological point of view.