VWF and thrombotic thrombocytopenic purpura: TMA, or more specifically, thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), is characterized by intraluminal platelet-rich thrombi, thrombocytopenia and organ infarction, which mainly results from deficiency of ADAMTS13, the protease cleaves von Willebrand, thus leading to the accumulation of ultra-large von Willebrand factor (ULVWF) multimers and the formation of platelet thrombus in human [54,55,56].