title: Endothelial injury and repair in systemic vasculitis of the young.
abstract: OBJECTIVE
  Endothelial injury is central to the pathogenesis of vasculitis. The purpose of this study was to assess how indices of endothelial injury and repair change during different stages of disease activity in children with primary systemic vasculitis (PSV).
  
  
  METHODS
  Fifty children with PSV, 17 children with nonvasculitic inflammatory diseases (pediatric inflammatory disease controls), 35 healthy age- and sex-matched pediatric controls, and 27 healthy adult controls were included in the study. Biomarkers examined were endothelial microparticles (EMPs), circulating endothelial cells (CECs), angiogenic growth factors, and endothelial progenitor cells (EPCs). EMP binding to annexin V, EMPs expressing CD144 or E-selectin, and EPCs expressing vascular endothelial growth factor receptor 2 (VEGFR-2), CD133, and CD34 were examined by flow cytometry. CECs were enumerated using immunomagnetic bead extraction techniques, and VEGF and angiopoietin 2 (Ang-2) were measured by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Levels of CD144+ EMPs, CECs, VEGF, and EPCs were all significantly elevated in children with active vasculitis as compared with healthy children, and the levels declined with remission-inducing therapy in the individual patients. Treatment-naive patients with active disease had significantly higher levels of VEGF and Ang-2 than did those with active disease who were receiving treatment, although the levels of CECs and EMPs remained high in both of these groups.
  
  
  CONCLUSIONS
  Elevation of the levels of CECs, EMPS, EPCs, VEGF, and Ang-2 occurs during active vasculitis in children. EPC responses to active vasculitis are different in children as compared with that observed in adults with vasculitis, and both CECs and EMPs can be used to monitor disease activity in children with vasculitis.
authors.affiliation: Institute of Child Health, University College London and Great Ormond Street Hospital National Health Service Trust, London, UK. l.clarke@imperial.ac.uk
authors.forename: L A
authors.initials: LA
authors.lastname: Clarke
authors.forename: Y
authors.initials: Y
authors.lastname: Hong
authors.forename: D
authors.initials: D
authors.lastname: Eleftheriou
authors.forename: V
authors.initials: V
authors.lastname: Shah
authors.forename: F
authors.initials: F
authors.lastname: Arrigoni
authors.forename: N J
authors.initials: NJ
authors.lastname: Klein
authors.forename: P A
authors.initials: PA
authors.lastname: Brogan
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D015820:Cadherins / Q000276:immunology / Q000378:metabolism; D055252:Cell-Derived Microparticles / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D018579:Patient Selection; D012720:Severity of Illness Index; D013234:Stem Cells / Q000276:immunology / Q000378:metabolism; D056647:Systemic Vasculitis / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000097:blood; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D042461:Vascular Endothelial Growth Factor A; D000099152:Cadherin 5