TPO and Hashimoto thyroiditis: In Hashimoto’s thyroiditis, autoimmune-mediated infiltration of the thyroid gland by innate immune cells (dendritic cells, macrophages, natural killer cells) and lymphocytes and the formation of antithyroid (thyroid peroxidase, TPO, and thyroglobulin, Tg) antibodies and TPO–complement complexes cause progressive fibrosis and damage which eventually results in hypothyroidism [10].