Von Willebrand factor, ADAMTS13, and thrombotic thrombocytopenic purpura.
Discoveries during the past decade have revolutionized our understanding of idiopathic thrombotic thrombocytopenic purpura (TTP). Most cases in adults are caused by acquired autoantibodies that inhibit ADAMTS13, a metalloprotease that cleaves von Willebrand factor within nascent platelet-rich thrombi to prevent hemolysis, thrombocytopenia, and tissue infarction. Although approximately 80% of patients respond to plasma exchange, which removes autoantibody and replenishes ADAMTS13, one third to one half of survivors develop refractory or relapsing disease. Intensive immunosuppressive therapy with rituximab appears to be effective as salvage therapy, and ongoing clinical trials should determine whether adjuvant rituximab with plasma exchange also is beneficial at first diagnosis. A major unanswered question is whether plasma exchange is effective for the subset of patients with idiopathic TTP who do not have severe ADAMTS13 deficiency.
Sadler
J Evan
JE
Department of Medicine, Washington University School of Medicine, St Louis, MO 63110, USA. esadler@im.wustl.edu
D051722:ADAM Proteins / Q000097:blood / Q000172:deficiency* / Q000276:immunology; D000071120:ADAMTS13 Protein; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D058846:Antibodies, Monoclonal, Murine-Derived; D001323:Autoantibodies / Q000097:blood; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D010951:Plasma Exchange; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D000069283:Rituximab; D014841:von Willebrand Factor / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D001323:Autoantibodies; D007166:Immunosuppressive Agents; D014841:von Willebrand Factor; D000069283:Rituximab; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human