Objective. Systemic lupus erythematosus (SLE) is a prototype of systemic autoimmune disease in which cytokines such as B lymphocyte chemoattractant (BLC, or CXC motif ligand 13, CXCL13) may play important roles in pathogenesis. We investigated the implications of CXCL13 in SLE and lupus nephritis. Methods. Serum samples from 425 patients with SLE and 106 healthy control individuals were analyzed for the concentration of CXCL13 by ELISA. Tissue expression of CXCL13 and its corresponding receptor CXCR5 were observed in lupus kidney. The CXCR5-bearing B cells in SLE patients were analyzed by flow cytometry. Results. Serum levels of CXCL13 were higher in SLE patients compared to controls. SLE patients with lupus nephritis or positive anti-dsDNA antibodies had significantly higher serum CXCL13 levels. The peripheral venous blood B cells that bear CXCR5 were more abundant in SLE patients as detected by flow cytometry. CXCR5 and CXCL13 were highly expressed in the renal cortex from patients with lupus nephritis. Conclusions. Our results suggest that BLC/CXCL13 as well as its corresponding receptor, CXCR5, may play important roles in the pathogenesis of SLE and in lupus nephritis.
