TPO and Hashimoto thyroiditis: Hashimoto’s thyroiditis (HT), also known as chronic autoimmune thyroiditis, is an autoimmune disease characterized by lymphocytic infiltration into and gradual damage to the thyroid parenchyma and the production of organ-specific anti-thyroid antibodies: anti-thyroid peroxidase (TPO-Ab) and anti-thyroglobulin (TG-Ab) [1,2,3].