Measurement of urinary annexin V by ELISA and its significance as a new urinary-marker of kidney disease

To confirm the significance of excretion of annexin V into the urine and th e change of urinary annexin V concentration in kidney disease, a sandwich e nzyme-linked immunosorbent assay (ELISA) was developed using two monoclonal antibodies. Urinary annexin V concentration was measured in healthy indivi duals and patients with kidney and other diseases. Urinary annexin V did no t change over a range of pH between 5.0 and 8.0, and was stable during the course of the study for 24 h at room temperature and for 8 days at 4 degree s C. The mean urinary annexin V concentration in 105 normal healthy individ uals was 1.5 +/- 1.5 ng/ml, while that in patients with nephrotic syndrome and systemic lupus erythematosis (SLE) nephritis was 9.3 +/- 9.1 and 6.6 +/ - 6.7 ng/ml, respectively, and that in IgA nephropathy and chronic renal fa ilure was 2.6 +/- 2.1 and 1.3 +/- 0.7 ng/ml, respectively. Annexin level co rrelated with urinary protein concentration(r = 0.717), but not the serum c reatinine concentration, blood urea nitrogen (BUN) and 24-h creatinine clea rance. Mean urinary annexin V concentration in patients with ischemic heart disease, hypertension, and diabetes mellitus was 1.4 +/- 1.0, 1.4 +/- 1.1, and 1.7 +/- 1.3 ng/ml, respectively. In one case of relapsing nephrotic sy ndrome, the urinary annexin V concentration was markedly increased in the e arly phase after admission and then decreased. This patient later required hemodialysis. These results suggest that a high urinary annexin V concentra tion may be an indicator of acute renal injury related to the urinary prote in level. (C) 2000 Elsevier Science B.V. All rights reserved.