Uromodulin as a Biomarker in Lupus Nephritis

Lupus nephritis (LN) is one of the most serious manifestations of systemic lupus erythematosus (SLE) and remains a major cause of chronic kidney disease and end-stage renal disease, particularly among young adults. Early diagnosis and accurate assessment of disease activity are essential to optimize treatment and improve long- term renal outcomes. Renal biopsy remains the gold standard for the diagnosis and classification of lupus nephritis, providing valuable information regarding histopathological activity and chronicity indices that guide therapeutic decisions. However, renal biopsy is an invasive procedure associated with potential complications and cannot be performed repeatedly for disease monitoring. Consequently, there is growing interest in identifying reliable non-invasive biomarkers that accurately reflect renal inflammation and chronic damage. Uromodulin, also known as Tamm-Horsfall protein, is the most abundant protein produced by the epithelial cells of the thick ascending limb of the loop of Henle. Experimental and clinical studies suggest that serum uromodulin is closely related to renal tubular integrity and overall nephron mass. Reduced serum uromodulin levels have been associated with impaired renal function and progressive kidney diseases. Although serum uromodulin has emerged as a promising biomarker in various chronic kidney disorders, its role in lupus nephritis remains insufficiently investigated. Determining whether serum uromodulin correlates with renal histopathological activity and chronicity indices may provide a valuable non-invasive tool for assessing disease severity and monitoring renal involvement.