[Clinical investigation of urinary dipeptidyl aminopeptidase IV (DAP IV) activity in patients with primary glomerular diseases].

To assess the role of urinary dipeptidyl aminopeptidase IV (DAP IV) in glomerular diseases, we measured urinary levels of DAP IV in 55 patients with chronic glomerulonephritis (CGN), 41 patients with nephrotic syndrome (NS), 21 patients with chronic renal failure (CRF) and 48 normal controls. The urinary DAP IV levels in patients with CGN were significantly higher than those in normal controls and were higher in patients with more active disease. The frequency of normal urinary DAP IV levels in patients with CGN was significantly lower than that of normal urinary N-acetyl-beta-D-glucosaminidase (NAG) levels in those with CGN. The urinary DAP IV levels in patients with NS were the highest among the 3 patient groups. The urinary DAP IV/g.protein ratio was significantly lower in the patients with minimal change nephrotic syndrome than in those with membranous glomerulonephritis or membranoproliferative glomerulonephritis. In both patients with CGN and those with NS, urinary DAP IV levels correlated significantly with the amounts of urinary protein and the urinary NAG levels. The urinary DAP IV levels in patients with CRF were lower than those in patients with CGN and NS who had normal GFR, and there was a significant negative correlation between the urinary DAP IV levels and the serum creatinine levels. We conclude that the measurement of urinary DAP IV is useful for detecting or monitoring glomerular disease.