Detection of Mature Macrophages in Urinary Sediments: Clinical Significance in Predicting Progressive Renal Disease

Abstract

The ability to predict the rate of progression of renal parenchymal disease may help in its clinical management. We undertook characterization of urinary macrophages obtained from patients with various renal diseases paving special attention to the differentiation from non-progressive to progressive renal diseases. A total of 84 patients were divided into one of three categories. A highly progressive group included patients with rapidly progressive glomerulonephritis, diabetic nephropathy, membranoproliferative glomerulonephropathy, primary focal segmental sclerosis and diffuse proliferative lupus nephropathy, moderately progressive group included those with IgA nephropathy and Alport's syndrome and non progressive group included patients with thin basement membrane nephropathy, minimal change nephrotic syndrome, idiopathic renal hematuria and urolithiasis. Urinary sediments were reacted with four monoclonal antibodies (CD68/macrophages vimentin, cytokeratin, and 25F9/mature macrophages). In normal individuals mature macrophages (25F9+ cells) were absent in urinary sediments. The number of 25F9+ cells in the urine was highest in the highly progressive group, less prominent in the moderately progressive group, and virtually absent in the non progressive group. The 25F9+ cells reacted with anti-CD68 and anti vimentin antibody, whereas the 25F9+ cells did not react with anti-cytokeratin antibody. These findings indicate that the detection of mature macrophages in urine is useful to estimate the prognosis of renal parenchymal diseases and may help to differentiate some glomerular diseases (e.g., thin basement membrane disease vs. Alport's syndrome, and minimal change nephrotic syndrome vs. primary focal segmental sclerosis).