Urinary WT1-positive cells as a non-invasive biomarker of crescent formation

Objective The purpose of this study was to assess the relationship between urinary WT1-positive cells (podocytes and active parietal epithelial cells) and WT1-positive cells in renal biopsy to investigate whether urinary WT1-positive cells are useful for detection of crescent formation. Methods Fifty-two patients with kidney disease were investigated (15 cases with crescentic lesions and 37 cases with non-crescentic lesions) for immunoenzyme staining using anti-WT1 antibody for urine cytology and renal biopsy. Numbers of WT1-positive cells in urine and renal biopsy were counted. Results There was no correlation between urinary WT1-positive cells and WT1-positive cells in renal biopsy. However, the number of urinary WT1-positive cells in patients with crescentic lesions was significantly higher than in patients with non-crescentic lesions. In addition, the best cut-off value to detect patients with crescentic lesions using urinary was 5 cells/10-mL (area under the concentration-time curve=0.735). Conclusions The results of our study suggest urinary WT1-positive cells can be used to detect patients with crescent formation using 5 cells/10-mL cutoff value. WT1-positive glomerular podocytes and parietal epithelial cells may be shed into urine in active glomerular disease. This study, investigating the relationship between WT1-positive cells in urine and in the renal biopsy found no correlation; however, the results do suggest that, using a cutoff value of 5 cells/10 mL, WT1 positive urinary cells can be used to detect patients with crescent formation.