title: Ticlopidine-Associated thrombotic thrombocytopenic purpura with an IgG-type inhibitor to von Willebrand factor-cleaving protease activity.
abstract: A 41-year-old Japanese man complained of a left-sided visual disturbance. Imaging by magnetic resonance angiography revealed a narrowing of the left internal cervical artery. Thus, ticlopidine (Tc) administration was started at a daily dose of 300 mg. However, 2 weeks later, severe thrombocytopenia, fever, nausea, and psychiatric symptoms developed; Tc was therefore discontinued. Based on the diagnostic hallmark of 5 clinical signs, the patient's disease was diagnosed as thrombotic thrombocytopenic purpura (TTP). Daily plasmapheresis was performed for the first 4 days, and the patient's clinical signs gradually improved. Von Willebrand factor-cleaving protease (vWF-CPase) activity in his plasma was less than 3% of that of the control sample at diagnosis, but that value recovered steadily following plasmapheresis. In addition, immunoglobulin G purified from the patient plasma inhibited vWF-CPase activity in normal plasma with a specific activity of 0.8 Bethesda units/mg. No sign of TTP relapse has been noted following cessation of Tc. Thus, it was concluded that the patient developed TTP by producing an inhibitory autoantibody against vWF-CPase activity that was presumably triggered by Tc administration.
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sugio
authors.forename: T
authors.initials: T
authors.lastname: Okamura
authors.forename: K
authors.initials: K
authors.lastname: Shimoda
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Yagi
authors.forename: H
authors.initials: H
authors.lastname: Ishizashi
authors.forename: Y
authors.initials: Y
authors.lastname: Niho
authors.forename: S
authors.initials: S
authors.lastname: Inaba
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimura
mesh_terms: D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D000328:Adult; D001157:Arterial Occlusive Diseases / Q000175:diagnosis / Q000188:drug therapy; D001323:Autoantibodies / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008666:Metalloendopeptidases / Q000097:blood*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D011697:Purpura, Thrombotic Thrombocytopenic / Q000139:chemically induced* / Q000276:immunology; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D010975:Platelet Aggregation Inhibitors; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D013988:Ticlopidine