title: Plasma DNA is Elevated in Patients with Deep Vein Thrombosis.
abstract: OBJECTIVE
  To investigate if plasma DNA is elevated in patients with deep vein thrombosis (DVT) and to determine whether there is a correlation with other biomarkers of DVT.
  
  
  BACKGROUND
  Leukocytes release DNA to form extracellular traps (ETs), which have recently been linked to experimental DVT. In baboons and mice, extracellular DNA co-localized with von Willebrand factor (VWF) in the thrombus and DNA appeared in circulation at the time of thrombus formation. ETs have not been associated with clinical DVT.
  
  
  METHODS
  From December 2008 to August 2010, patients were screened through the University of Michigan Diagnostic Vascular Unit and were divided into three distinct groups: 1) the DVT positive group, consisting of patients who were symptomatic for DVT, which was confirmed by compression duplex ultrasound (n=47); 2) the DVT negative group, consisting of patients that present with swelling and leg pain but had a negative compression duplex ultrasound, (n=28); and 3) a control group of healthy non-pregnant volunteers without signs or symptoms of active or previous DVT (n=19). Patients were excluded if they were less than 18 years of age, unwillingness to consent, pregnant, on an anticoagulant therapy, or diagnosed with isolated calf vein thrombosis.
  
  
  METHODS
  Blood was collected for circulating DNA, CRP, D-dimer, VWF activity, myeloperoxidase (MPO), ADAMTS13 and VWF. The Wells score for a patient's risk of DVT was assessed. The Receiver Operating Characteristic (ROC) curve was generated to determine the strength of the relationship between circulating DNA levels and the presence of DVT. A Spearman correlation was performed to determine the relationship between the DNA levels and the biomarkers and the Wells score. Additionally the ratio of ADAMTS13/VWF was assessed.
  
  
  RESULTS
  Our results showed that circulating DNA (a surrogate marker for NETs) was significantly elevated in DVT patients, compared to both DVT negative patients (57.7±6.3 vs. 17.9±3.5ng/mL, P<.01) and controls (57.7±6.3 vs. 23.9±2.1ng/mL, P<.01). There was a strong positive correlation with CRP (P<.01), D-dimer (P<.01), VWF (P<.01), Wells score (P<.01) and myeloperoxidase (MPO) (P<.01), along with a strong negative correlation with ADAMTS13 (P<.01) and the ADAMTS13/VWF ratio. The logistic regression model showed a strong association between plasma DNA and the presence of DVT (ROC curve was determined to be 0.814).
  
  
  CONCLUSIONS
  Plasma DNA is elevated in patients with deep vein thrombosis and correlates with biomarkers of DVT. A strong correlation between circulating DNA and MPO suggests that neutrophils may be a source of plasma DNA in patients with DVT.
authors.affiliation: Department of Surgery, Section of Vascular Surgery, Conrad Jobst Vascular Research Laboratories, Harvard Medical School, Boston, MA, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Diaz
authors.affiliation: Immune Disease Institute; Program in Cellular and Molecular Medicine, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Fuchs
authors.affiliation: Bern University Hospital and the University of Bern, Department of Hematology and Central Hematology Laboratory, Bern, Switzerland.
authors.forename: T O
authors.initials: TO
authors.lastname: Jackson
authors.affiliation: Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Kremer Hovinga
authors.affiliation: School of Public Health, University of Michigan, Ann Arbor, MI, USA.
authors.forename: B
authors.initials: B
authors.lastname: Lämmle
authors.forename: P K
authors.initials: PK
authors.lastname: Henke
authors.forename: D D
authors.initials: DD
authors.lastname: Myers
authors.forename: D D
authors.initials: DD
authors.lastname: Wagner
authors.forename: T W
authors.initials: TW
authors.lastname: Wakefield