Urine osteoprotegerin and monocyte chemoattractant protein-1 in lupus nephritis.

Objective: Renal biopsy is the "gold standard" to determine renal activity in systemic lupus erythematosus (SLE), but it is expensive, invasive, and carries risk. Osteoprotegerin (OPG) is produced by the heart, lungs, kidney, and bone. Monocyte chemoattractant protein-1 (MCP-1), a chemotactic cytokine, is involved in the progression of glomerular and tubulointerstitial injury.