Analysis of urinary mononuclear cells as markers of renal injury

The presence of macrophages(M phi) in the urine of patients with glomerulonephritis(GN) reflects the pathological events in the kidney, and we have discovered the following correlations between the M phi phenotype and the pattern of renal injury. 1) Urinary macrophage(M phi) counts increase in patients with proliferative GN, especially in the presence of active glomerular lesions(glomerular tuft necrosis, crescent, and endocapillary proliferation). In patients with hematuria, a combination of urinary M phi and T-lymphocyte counts can be used to differentiate proliferative GN from non-proliferative renal disease(hereditary nephropathy and idiopathic renal hematuria). 2) The urinary M phi of patients with active proliferative GN express Fc gamma RIII(CD16) regardless of the type of GN. 3) There are two types of urinary CD68+ cells, CD68+25F9- cells(infiltrating M phi) and CD68+25F9+ cells(mature M phi). The CD68+25F9- cell counts in the urine correlate well with the activity of proliferative GN, and the CD68+25F9+ cell counts in the urine correlate with the magnitude of non-selective proteinuria and with the subsequent decline of renal function. The CD68+25F9+ cell count increase in the urine of patients with focal segmental glomerular sclerosis, but their numbers are negligible in minimal change nephrotic syndrome. These findings indicate that analysis of the urinary M phi phenotype is a useful strategy for evaluating renal injury as a "risk-free renal biopsy".