If TPO is expressed by keratinocytes, it is possible that anti-TPO autoAbs may function in a similar manner as they do in Hashimoto's thyroiditis, inflicting cell damage via compliment fixation and/or antibody dependent cell-mediated cytotoxicity (ADCC) (139–145), though the paucity of immune cell infiltrate characteristic of PV may exclude ADCC as a major contribution to disease pathogenesis. This evidence concerns the gene TPO and Hashimoto thyroiditis.