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C4?derived activation fragments are the only complement ligands present on the surfaces of normal erythrocytes. The significance of this observation is unknown, and the role of erythrocyte?bound C4 (E?C4) in human disease has not been explored. More than any other human disease, the pathogenesis of systemic lupus erythematosus (SLE) has been characterized by defects in clearance of complement?bearing immune complexes via erythrocytes expressing complement receptor 1 (CR1). This study was undertaken to determine whether these functional defects might be reflected by abnormal patterns of E?C4 and E?CR1 expression on erythrocytes of patients with SLE.We conducted a cross?sectional study of 100 patients with SLE, 133 patients with other diseases, and 84 healthy controls. Erythrocytes were characterized by indirect immunofluorescence and by flow cytometry for determination of levels of C4d and CR1.Patients with SLE had higher levels of E?C4d and lower levels of E?CR1 than did patients with other diseases (P ? 0.001) or healthy controls (P ? 0.001). The test was 81% sensitive and 91% specific for SLE versus healthy controls and 72% sensitive and 79% specific for SLE versus other diseases, and it had an overall negative predictive value of 92%.This is the first report of abnormal levels of E?C4d in human disease. We found that abnormally high levels of E?C4d and low levels of E?CR1 are characteristic of SLE, and combined measurement of the 2 molecules has high diagnostic sensitivity and specificity for lupus. Determination of E?C4d/E?CR1 levels may be a useful addition to current tests and criteria for SLE diagnosis. [ABSTRACT FROM AUTHOR]

Objectives. To determine the associations between depression, cardiovascular risk factors and coronary artery calcification (CAC) in women with SLE and controls. Methods. CAC was measured using electron-beam CT (EBCT). Traditional, inflammatory and lupus-related risk factors as well as depressive symptoms (Center for Epidemiologic Studies Depression Scale—CES-D) were measured at a single study visit in 161 women with SLE and 161 age- and race frequency-matched female healthy controls. Results. Women with SLE reported more depressive symptoms than controls, with 27% of SLE and 15% of controls having CES-D scores suggestive of clinical depression. SLE women were more likely to have CAC, as well as more severe CAC compared with controls. Among the SLE women, depression was associated with greater than 2-fold odds of having any CAC [odds ratio (OR) 2.48; 95% CI 1.05, 5.87; P = 0.04], independent of traditional risk factors (age, hypertension and triglycerides) and inflammatory markers. However, when BMI was included among the covariates, the association between depression and CAC was attenuated, indicating the potential mediating role of BMI. Depression was not a risk factor for CAC in controls. Conclusions. In women with SLE, depression was associated with CAC. This association was mediated by BMI. Depression and adiposity may add to the inflammatory burden of SLE, thus contributing to cardiovascular disease risk. [ABSTRACT FROM AUTHOR]