BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) affects 1 in 1600 to 1 in 5000 patients who receive ticlopidine, but little is known about the pathogenesis of this complication. OBJECTIVE: To investigate whether von Willebrand factor (vWF), which has been associated with idiopathic TTP, is involved in the pathogenesis of ticlopidine-associated TTP. DESIGN: Case series. SETTING: Three tertiary care, university-affiliated medical centers. PATIENTS: Seven patients who developed TTP 2 to 7 weeks after initiation of ticlopidine therapy. Controls were 7 consecutive patients without thrombocytopenia who had been receiving ticlopidine for 3 to 5 weeks and 10 randomly selected hospitalized patients. MEASUREMENTS: Platelet-bound vWF in patients' EDTA-anticoagulated whole blood samples; vWF proteinase activity in patients' plasma samples; inhibitory activity of IgG isolated from patients' plasma samples against the proteinase from the controls' plasma samples; and vWF multimeric patterns in patients' EDTA-anticoagulated plasma samples. RESULTS: Binding of vWF to single platelets was increased in the three patients tested during the most thrombocytopenic phase of TTP episodes. Initial plasma samples from all seven patients lacked the largest vWF multimers and were severely deficient in vWF metalloproteinase. IgG molecules, isolated from plasma samples of five patients, inhibited metalloproteinase in plasma samples from the controls. In patients examined, these abnormalities resolved upon the remission that accompanied plasma exchange and discontinuation of ticlopidine therapy. CONCLUSION: In the patients who developed ticlopidine-associated TTP, autoantibodies to the vWF metalloproteinase were formed; this led to the same type of vWF abnormalities observed in patients with idiopathic acute TTP. The findings suggest that failure to process large and unusually large vWF multimers in vivo caused binding of vWF to platelets, systemic platelet thrombosis, and TTP.
BACKGROUND:Thrombotic thrombocytopenic purpura (TTP) affects 1 in 1600 to 1 in 5000 patients who receive ticlopidine, but little is known about the pathogenesis of this complication. OBJECTIVE: To investigate whether von Willebrand factor (vWF), which has been associated with idiopathic TTP, is involved in the pathogenesis of ticlopidine-associated TTP. DESIGN: Case series. SETTING: Three tertiary care, university-affiliated medical centers. PATIENTS: Seven patients who developed TTP 2 to 7 weeks after initiation of ticlopidine therapy. Controls were 7 consecutive patients without thrombocytopenia who had been receiving ticlopidine for 3 to 5 weeks and 10 randomly selected hospitalized patients. MEASUREMENTS: Platelet-bound vWF in patients' EDTA-anticoagulated whole blood samples; vWF proteinase activity in patients' plasma samples; inhibitory activity of IgG isolated from patients' plasma samples against the proteinase from the controls' plasma samples; and vWF multimeric patterns in patients' EDTA-anticoagulated plasma samples. RESULTS: Binding of vWF to single platelets was increased in the three patients tested during the most thrombocytopenic phase of TTP episodes. Initial plasma samples from all seven patients lacked the largest vWF multimers and were severely deficient in vWF metalloproteinase. IgG molecules, isolated from plasma samples of five patients, inhibited metalloproteinase in plasma samples from the controls. In patients examined, these abnormalities resolved upon the remission that accompanied plasma exchange and discontinuation of ticlopidine therapy. CONCLUSION: In the patients who developed ticlopidine-associated TTP, autoantibodies to the vWF metalloproteinase were formed; this led to the same type of vWF abnormalities observed in patients with idiopathic acute TTP. The findings suggest that failure to process large and unusually large vWF multimers in vivo caused binding of vWF to platelets, systemic platelet thrombosis, and TTP.
Authors: J L Moake; C K Rudy; J H Troll; M J Weinstein; N M Colannino; J Azocar; R H Seder; S L Hong; D Deykin Journal: N Engl J Med Date: 1982-12-02 Impact factor: 91.245
Authors: T W Chow; N A Turner; M Chintagumpala; P D McPherson; L H Nolasco; L Rice; J D Hellums; J L Moake Journal: Am J Hematol Date: 1998-04 Impact factor: 10.047
Authors: Charles L Bennett; Sony Jacob; Brianne L Dunn; Peter Georgantopoulos; X Long Zheng; Hau C Kwaan; June M McKoy; Jametta S Magwood; Zaina P Qureshi; Nicholas Bandarenko; Jeffrey L Winters; Thomas J Raife; Patricia M Carey; Ravindra Sarode; Joseph E Kiss; Constance Danielson; Thomas L Ortel; William F Clark; Richard J Ablin; Gail Rock; Masanori Matsumoto; Yoshihiro Fujimura Journal: Br J Haematol Date: 2013-03-27 Impact factor: 6.998
Authors: Fengxiao Bu; Nicolo Ghiringhelli Borsa; Michael B Jones; Erika Takanami; Carla Nishimura; Jill J Hauer; Hela Azaiez; Elizabeth A Black-Ziegelbein; Nicole C Meyer; Diana L Kolbe; Yingyue Li; Kathy Frees; Michael J Schnieders; Christie Thomas; Carla Nester; Richard J H Smith Journal: J Am Soc Nephrol Date: 2015-08-17 Impact factor: 10.121