Cardiovascular events are markedly increased in systemic lupus erythematosus (SLE), and the mechanism of atherogenesis remains poorly understood. Several methods have been employed to assess endothelial function, among these is the measurement of biomarkers of endothelial activation and dysfunction [intercellular adhesion molecule (ICAM-1)]. It has been reported that such biomarkers play a more important role than traditional risk factors in cardiovascular disease. The objectives of this study were to determine the level of ICAM-1 as markers of endothelial dysfunction in 40 Egyptian patients who have SLE with various degrees of activity and to investigate their relationship to disease activity. Sixty people (40 with SLE and 20 healthy as the control group) were the subject of this study; their clinical disease activity was scored according to the SLE disease activity index (SLEDAI), and serum sampling was obtained for ICAM-1 level assay. Renal biopsy was carried out and examined by light microscopy by a pathologist blinded to the clinical activity. The mean level of ICAM-1 was significantly higher in SLE patients with active disease (826.05 +/- 367.1 Pg/ml) compared to those with inactive disease (441.33 +/- 225.19 Pg/ml) and the healthy control volunteers (111.5 +/- 17.36 Pg/ml). There was a positive correlation between serum ICAM-1 and SLEDAI (r = 0.66). A high concentration of soluble ICAM-1 in SLE patients with nephritis is reported in this paper. Our finding of increased concentrations of ICAM-1 in SLE patients with nephritis underlines the importance of inflammation and endothelial involvement in this disease, but their predictive value in the disease monitoring need to be further studied.