Association of circulating immune complexes with glomerular proteinuria in patients with transitional cell carcinoma of the urinary bladder.

The presence of circulating immune complexes and the correlation between the amount of immune complexes and glomerular proteinuria was studied in 20 patients with urothelial bladder tumors followed by cystoscopies for 6-18 months. Circulating immune complexes, measured by the PEG-CC, PICRIA and C1q-ELISA assays, occurred more frequently in cases with residual or recurrent tumors than without tumors, and most frequently in cases with large tumors and a high grade of malignancy. Glomerular proteinuria, defined as the increased relative clearance of albumin, transferrin and haptoglobin, occurred in almost all cases with increased immune complex concentrations. Both glomerular proteinuria and the severity of proteinuria was significantly related to the immune complex concentration.