title: Pathophysiology of thrombotic thrombocytopenic purpura.
abstract: Thrombotic thrombocytopenic purpura (TTP) is a disorder with characteristic von Willebrand factor (VWF)-rich microthrombi affecting the arterioles and capillaries of multiple organs. The disorder frequently leads to early death unless the patients are treated with plasma exchange or infusion. Studies in the last decade have provided ample evidence to support that TTP is caused by deficiency of a plasma metalloprotease, ADAMTS13. When exposed to high shear stress in the microcirculation, VWF and platelets are prone to form aggregates. This propensity of VWF and platelet to form microvascular thrombosis is mitigated by ADAMTS13, which cleaves VWF before it is activated by shear stress to cause platelet aggregation in the circulation. Deficiency of ADAMTS13, due to autoimmune inhibitors in patients with acquired TTP and mutations of the ADAMTS13 gene in hereditary cases, leads to VWF-platelet aggregation and microvascular thrombosis of TTP. In this review, we discuss the current knowledge on the pathogenesis, diagnosis and management of TTP, address the ongoing controversies, and indicate the directions of future investigations.
authors.affiliation: Section of Thrombosis and Hemostasis, Division of Hematology and Oncology, H046, Pennsylvania State University, Milton S. Hershey College of Medicine, Pennsylvania State Cancer Institute, 500 University Drive, Hershey, PA 17033, USA. htsai@hmc.psu.edu
authors.forename: Han-Mou
authors.initials: HM
authors.lastname: Tsai
mesh_terms: D051722:ADAM Proteins / Q000097:blood* / Q000172:deficiency / Q000235:genetics; D000071120:ADAMTS13 Protein; D006801:Humans; D010974:Platelet Aggregation / Q000502:physiology*; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000235:genetics / Q000503:physiopathology*; D013314:Stress, Mechanical; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human