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Flow Cytometry Analysis of Tissue Factor Expression in Human Platelets
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Antibodies from patients with heparin-induced thrombocytopenia stimulate monocytic cells to express tissue factor and

G M Arepally1, I M Mayer

  • 1Cancer Research and Treatment Center and Department of Medicine, the University of New Mexico Health Sciences Center, Albuquerque, NM, USA. arepally@unm.edu

Blood
|August 9, 2001
PubMed

Thrombosis is a life-threatening complication that occurs in a subset of patients with heparin-induced thrombocytopenia (HITT). The pathogenic mechanisms underlying the variable occurrence of thrombosis in HITT is poorly understood. It was hypothesized that monocyte activation leading to tissue factor expression may play a role in promoting a thrombogenic state in HITT. This study demonstrates that a human platelet factor 4 (PF4)/heparin-specific murine monoclonal antibody (KKO) binds to peripheral blood-derived human monocytes in a PF4-dependent manner. KKO and antibodies from patients with HITT induce monocytes to synthesize and secrete interleukin-8 and induce cell-surface procoagulant activity, which is abrogated following treatment with antihuman tissue factor antibody. The findings suggest a novel mechanism by which PF4/heparin antibodies may promote a hypercoagulable state in patients with HITT. (Blood. 2001;98:1252-1254)

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