title: Circulating endothelial progenitor cells in patients with ANCA-associated vasculitis.
abstract: OBJECTIVE
  Bone marrow-derived endothelial progenitor cells (EPCs) are believed to contribute to endothelial repair after vascular damage. To investigate the potential for microvascular repair in patients with ANCA-associated vasculitis (AAV), we conducted a cross-sectional study determining the number of circulating EPCs in patients with AAV, chronic uremia, atherosclerosis, and in healthy volunteers.
  
  
  METHODS
  The number of circulating EPCs was determined by colony-forming assay in 41 patients with AAV, 15 hemodialysis patients (without vasculitis), 13 patients with peripheral arterial occlusive disease (PAOD), and 25 healthy controls.
  
  
  RESULTS
  Patients with AAV had a significantly lower number of CFU-Hill than healthy subjects (median 0.3 vs. 19.5 CFU-Hill/ml blood, p < 0.0001), but not than patients on hemodialysis or with PAOD. Neither institution of treatment nor entering remission increased the number of EPCs in AAV patients. The number of EPCs did not correlate with markers of disease activity. AAV patients with glomerular filtration rate <15 ml/min had an even lower number of circulating EPCs than patients with better preserved renal function (median 0.05 vs. 1.2 CFU-Hill/ml, p = 0.015) and patients with anti-MPO positivity had a trend towards a higher number of EPCs than patients with anti-PR3 antibodies (median 3.1 vs. 0.18 CFU-Hill/ml, p = 0.06).
  
  
  CONCLUSIONS
  Patients with AAV have a significant and persistent deficiency of circulating EPCs. A low number of EPCs could reflect an impaired mechanism of vascular repair and may contribute to repeated relapses in these patients.
authors.affiliation: Department of Nephrology, First Faculty of Medicine, Charles University in Prague, General Teaching Hospital, Prague, Czech Republic. jzavada@centrum.cz
authors.forename: Jakub
authors.initials: J
authors.lastname: Závada
authors.forename: Linda
authors.initials: L
authors.lastname: Kideryová
authors.forename: Robert
authors.initials: R
authors.lastname: Pytlík
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Vanková
authors.forename: Vladimír
authors.initials: V
authors.lastname: Tesar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic; D050197:Atherosclerosis; D001773:Blood Cells; D002452:Cell Count; D003114:Colony-Forming Units Assay; D003430:Cross-Sectional Studies; D042783:Endothelial Cells / Q000473:pathology*; D005260:Female; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases; D013234:Stem Cells / Q000473:pathology*; D014511:Uremia; D014657:Vasculitis / Q000097:blood* / Q000276:immunology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic