Anti-TPO aAbs are invaluable markers of thyroid autoimmune response and have been shown to exert both in vitro and in vivo cytotoxic functions such as C3 complement activation (Wadeleux et al, 1989; Chiovato et al, 1993; Parkes et al, 1994) and antibody-dependent cell-mediated cytotoxicity (ADCC) (Bogner et al, 1989; Rodien et al, 1996; Guo et al, 1997; Metcalfe et al, 1997; Rebuffat et al, 2008). Here, TPO is linked to autoimmune thyroid disease.