Circulating Endothelial Cells in Systemic Lupus Erythematosus:Correlation with the Activity of the Disease

Background. Quantification of circulating endothelial cells (CECs) in peripheral blood is developing as anovel and reproducible method of assessing endothelial damage / dysfunction. Accordingly, elevated levelsof CECs may be a marker of vascular injury in systemic lupus erythematous (SLE). Objective. This study was undertaken to assess the blood level of CECs in SLE to correlate its level with the activity of the disease and to examine the possibility that the presence of increased numbers of CECs can be used as amarker of immune-mediated vessel damage. Patients and methods. The study included 33 patients with SLE and 20 healthy controls. They were subjected to clinical examination together with laboratory investigations including complete blood picture (CBC), ESR, urine analysis, renal function test, C3, C4,ANA, anti-ds DNA antibody, antiphospholipid (IgM IgG) antibodies and quantification of CECs in blood.CECs were calculated using flow cytometry after staining with mouse anti-human CD45 antibody(pan-leukocyte marker), mouse anti-human CD 146 antibody (endothelial cell marker) and7-amino-actinomycin D (7-AAD) viability marker. CECs were defined as the live cells with 7-AA Dnegative, CD45 negative and CD146 positive. Results. Numbers of CECs were significantly higher inpatients with SLE compared with those in healthy control (mean k SD 38.6 f 21.2 versus 7.4 + 3.4).Furthermore, CECs were correlated positively with SLE disease activity index (SLEDAI) score, ESR and anti-ds DNA. CECs from patients with vasculitic skin lesions, renal and C.N.S manifestation were significantly higher than patients free from the previous signs. Conclusion. Increased number of CEC sobserved in patients with SLE was associated with the active phase of the disease and may represent amarker of wide spread endothelial injury.