Caplacizumab (His Tag) is a humanized anti-von Willebrand factor (vWF) nanobody. Caplacizumab (His Tag) inhibits the binding of vWF with platelet glycoprotein (GP) Ibα. Caplacizumab (His Tag) inhibits the vWF-mediated platelet adhesion and prevents further microthrombi formation. Caplacizumab (His Tag) can be used for the research of thrombotic thrombocytopenic purpura (TTP) [1][2][3][4].