TPO and vitiligo: The autoimmune hypothesis is the most widely accepted and holds that serum thyroid antibodies such as thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb) separately bind to thyroglobulin (Tg) and thyroid peroxidase (TPO) expressed in melanocytes, resulting in their activation, which may partially account for the destruction of the melanocytes in vitiligo [45].