REGULAR ARTICLE Monocytes and plasma tissue factor levels in normal individuals and patients with deep venous thrombosis of the lower limbs: Potential diagnostic tools? B Lauro M. Vieira a , Luci M.S. Dusse a , Ana P. Fernandes a , Olindo A. Martins-Filho b , Marcos de Bastos c , Mo ˆnica F.R. Ferreira c , Alan J. Cooper e , Bashir A. Lwaleed d,e, * , Maria G. Carvalho a a Faculty of Pharmacy — Federal University of Minas Gerais, Brazil b Research Center Rene´ Rachou-FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil c Governador Israel Pinheiro Hospital — IPSEMG, Belo Horizonte, Minas Gerais, Brazil d University of Southampton, Southampton, United Kingdom e Southampton Hospitals NHS Trust, Southampton, United Kingdom Received 14 September 2005; received in revised form 6 January 2006; accepted 8 January 2006 Available online 9 March 2006 Abstract Introduction: Tissue factor (TF) is the main physiological initiator of blood coagulation; it is membrane-bound on monocytes (mTF) and free in plasma (pTF). Abnormal expression of TF by monocytes has been implicated in various diseases. We therefore quantified monocytes expressing TF and pTF levels in patients with lower- limb deep venous thrombosis (DVT). Materials and methods: DVT was confirmed by Duplex Scan. Blood mTF levels under resting condition (baseline), after incubation without (unstimulated) and with (stimulated) lipopolysaccharide (LPS), and total mTF levels were determined by flow cytometry using two analytical methods (Histogram and Quadrant-Statistics). Plasma TF levels were measured using an enzyme-linked immunoabsorbent assay (ELISA). Results were compared with age-matched controls. 0049-3848/$ - see front matter D 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.thromres.2006.01.005 B The content of the manuscript has been presented in the last meetings of the ISTH and BSH. * Corresponding author. Department of Urology, Central block, Level E, West Wing, Mailpoint 67, Southampton University Hospitals NHS Trust, Tremona Road, Southampton SO16 6YD, UK. Tel.: +44 2380 796559; fax: +44 2380 796922. E-mail address: bashir@soton.ac.uk (B.A. Lwaleed). KEYWORDS Deep venous thrombosis (DVT); Monocytes; Endothelial cells; Plasma; Tissue factor; Flow cytometry; ELISA; Diagnosis; Original article Thrombosis Research (2007) 119, 157 — 165 intl.elsevierhealth.com/journals/thre