PT - JOURNAL ARTICLE AU - Adnan N. Kiani AU - Kristen Johnson AU - Catherine Chen AU - Edward Diehl AU - Huaizhong Hu AU - Ganesh Vasudevan AU - Sukhminder Singh AU - Laurence S. Magder AU - Stuart J. Knechtle AU - Michelle Petri TI - Urine Osteoprotegerin and Monocyte Chemoattractant Protein-1 in Lupus Nephritis AID - 10.3899/jrheum.081112 DP - 2009 Jul 31 TA - The Journal of Rheumatology PG - jrheum.081112 4099 - http://www.jrheum.org/content/early/2009/07/28/jrheum.081112.short 4100 - http://www.jrheum.org/content/early/2009/07/28/jrheum.081112.full AB - 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. We investigated both urine OPG and MCP-1 as potential biomarkers for lupus nephritis. Methods Our subjects, 87 patients with SLE (88% women; 48%AfricanAmerican, 41% Caucasian, 11% other), mean age 44 years, were followed monthly to quarterly. Urinary OPG (pg/ml) andMCP-1 (pg/ml) were measured (Luminex MAP bead assay). Results OPG concentrations were strongly associated with global disease activity and with both renal activity on a visual analog scale (VAS) (p = 0.0006) and renal disease activity descriptors of the SELENA SLEDAI, including hematuria (p = 0.001) and a positive anti-dsDNA (p = 0.013). MCP-1 was also associated with the renal VAS (p = 0.032), renal disease activity descriptors of SELENA SLEDAI, including hematuria (p = 0.027), and with a positive anti-dsDNA (p = 0.016). We also examined the relationship between the biomarkers and having a urine protein to creatinine ratio (pr/cr) ≥ 0.5. Among patients with medium or high OPG, 46% had urine pr/cr ≥ 0.5, compared to only 23% among those with low OPG (p = 0.032). The 2 biomarkers were strongly correlated with each other (Spearman correlation coefficient 0.77, p < 0.0001). Conclusion The lack of availability of urine biomarkers has hampered development of new therapies for lupus nephritis. Urine MCP-1 and OPG were both associated with measures of lupus renal disease activity. Medium or high levels of OPG were predictive of a urine protein/creatinine ratio of ≥ 0.5. Further study, including longitudinal assessment and correlation with concurrent renal biopsies, is necessary before this assay can be used in the routine clinic setting.