title: Circulating endothelial cells as a prognostic marker in thrombotic microangiopathy.
abstract: BACKGROUND
  Circulating endothelial cells (CECs) are a reliable marker of disease activity in a variety of vascular disorders. Damage to microvascular endothelial cells is a hallmark of thrombotic microangiopathy (TMA). The aim of this study is to identify and count CECs during the course of TMA and evaluate whether cell numbers may serve as a prognostic marker in patients undergoing plasma exchange.
  
  
  METHODS
  Fifteen patients (8 women, 7 men) aged 31 to 66 years with TMA of different causes were studied before and after 4 sessions of plasma exchange. CECs were isolated by using anti-CD146-driven immunomagnetic isolation and counted after staining with Ulex Europaeus lectin-1.
  
  
  RESULTS
  Numbers of CECs were markedly elevated in all patients before treatment (64 to 672 CEC/mL; mean, 320 +/- 205 CEC/mL) compared with healthy controls (0 to 16 CEC/mL; mean, 6.4 +/- 4.2 CEC/mL; P < 0.001). Patients with a favorable outcome had significantly greater initial CEC levels (mean, 426 +/- 175 CEC/mL; P < 0.001), and cell numbers decreased significantly after 4 treatments of plasma exchange (mean, 101 +/- 53 CEC/mL; P = 0.001). Patients with disease unresponsive to plasma exchange presented with lower initial CEC levels (mean, 108 +/- 36 CEC/mL), and numbers failed to decrease after plasma exchange (mean, 114 +/- 57 CEC/mL; P = 0.827).
  
  
  CONCLUSIONS
  Markedly elevated numbers of CECs reflect severe and widespread endothelial damage in patients with TMA. Cell numbers at presentation and their degree of decrease after 4 sessions of plasma exchange could provide important prognostic clues.
authors.affiliation: Department of Medicine, Division of Nephrology, Hannover Medical School, Hannover, Germany. erdbruegger.uta@mh-hannover.de
authors.forename: Uta
authors.initials: U
authors.lastname: Erdbruegger
authors.forename: Alexander
authors.initials: A
authors.lastname: Woywodt
authors.forename: Torsten
authors.initials: T
authors.lastname: Kirsch
authors.forename: Hermann
authors.initials: H
authors.lastname: Haller
authors.forename: Marion
authors.initials: M
authors.lastname: Haubitz
mesh_terms: D000328:Adult; D000368:Aged; D000743:Anemia, Hemolytic / Q000097:blood* / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D042783:Endothelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000473:pathology; D008875:Middle Aged; D010974:Platelet Aggregation / Q000502:physiology; D011379:Prognosis; D013921:Thrombocytopenia / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D013927:Thrombosis / Q000097:blood* / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology
chemical_list: D015415:Biomarkers