The anti-human FcγRIIIa antibody 3G8 has shown encouraging clinical efficacy in patients with primary immune thrombocytopenia but also elicited severe adverse effects, likely due to Fc-mediated FcγRIIIA crosslinking via ITAM signaling and consecutive aberrant immune activation [82]. Here, FCGR3A is linked to autoimmune thrombocytopenic purpura.