title: Endothelial dysfunction in systemic lupus patients with low disease activity: evaluation by quantification and characterization of circulating endothelial microparticles, role of anti-endothelial cell antibodies.
abstract: OBJECTIVE
  We attempted to evaluate endothelial dysfunction and the role of AECAs in systemic lupus (SL) with low disease activity. We quantified endothelial microparticles (EMps) and attempted to find the best flow cytometry method for that purpose.
  
  
  METHODS
  CD105, CD144 and CD146 were tested, individually or in combination, on EMp-enriched plasma. Twenty-three healthy blood donors and 27 SL patients were evaluated. SL patients with a SLEDAI <10 (median 2.6) were evaluated in our outpatient clinic. For each patient, EMps (CD105-CD146(+), CD45(-)) and AECAs were quantified and characterized.
  
  
  RESULTS
  The monochrome composite marker CD105-CD146 appeared to be the most efficient in detecting EMps. SL patients had more circulating EMps than healthy donors: respective median values were 2575 and 130 EMps/microl (P < 0.001). SL patients had more CD54(+) and CD54(-) EMps than healthy donors (496 vs 34 EMps CD54(+)/microl, P < 0.0001; 1875 vs 89 EMps CD54(-)/microl, P < 0.0001). The ratio CD54(+) EMps/total EMps was lower for lupus patients than for healthy individuals (20.3 vs 33.7%, P = 0.03). Twenty-four patients (89%) were positive for AECAs. EMp counts were not significantly higher for patients with AECAs.
  
  
  CONCLUSIONS
  Monochrome composite marker is efficient in detecting the whole population of EMps using flow cytometry. SL patients with low disease activity have a marked endothelial dysfunction. EMps released from the endothelium originate from activated and non-activated cells. AECAs do not seem to be the main cause of endothelial dysfunction in this population.
authors.affiliation: AP-HP, Internal Medicine Department, Hôpital Européen Georges Pompidou, France. arnaud.duval@sls.aphp.fr
authors.forename: Arnaud
authors.initials: A
authors.lastname: Duval
authors.forename: Dominique
authors.initials: D
authors.lastname: Helley
authors.forename: Loïc
authors.initials: L
authors.lastname: Capron
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
authors.forename: Yves
authors.initials: Y
authors.lastname: Renaudineau
authors.forename: Sylvain
authors.initials: S
authors.lastname: Dubucquoi
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Fischer
authors.forename: Eric
authors.initials: E
authors.lastname: Hachulla
mesh_terms: D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000378:metabolism*; D001323:Autoantibodies / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D042783:Endothelial Cells / Q000276:immunology*; D004730:Endothelium, Vascular / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015415:Biomarkers; C087589:anti-endothelial cell antibody