Plasma C4d as marker for lupus nephritis in systemic lupus erythematosus

Low serum levels of complement components C3 and C4 have been used for over 50 years to indicate lupus activity and are included in the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Because levels of C3 or C4 depend not only on complement activation but also on the rate of synthesis, the measurement of complement activation products has been suggested as a more specific SLE biomarker [2-4]. High C4d levels as well as low C3 levels associated significantly with LN (Fig. 3d). Because the presence of anti-dsDNA antibodies is known to associate with LN [10], we investigated their c... Mehr ...