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.
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.
Duval
Arnaud
A
AP-HP, Internal Medicine Department, Hôpital Européen Georges Pompidou, France. arnaud.duval@sls.aphp.fr
Helley
Dominique
D
Capron
Loïc
L
Youinou
Pierre
P
Renaudineau
Yves
Y
Dubucquoi
Sylvain
S
Fischer
Anne-Marie
AM
Hachulla
Eric
E
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
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015415:Biomarkers; C087589:anti-endothelial cell antibody