C3 and systemic lupus erythematosus: To this end, we evaluated concentrations of Wnt-3A, a ligand of Wnt/β-catenin signaling, FZD-8, a receptor of the signaling, and DKK-1 in the sera and urine of 111 SLE patients in a single center and investigated the clinical significance of such antibodies alone or in combination with anti-dsDNA antibodies and/or serum levels of C3 and C4 for accessing active nephritis in SLE patients in the present study.