Proteinuria as diagnostic marker after human kidney transplantation.

Molecular weight analyses of urinary proteins in 34 patients following cadaveric kidney transplantation were performed by SDS-PAA-electrophoresis in order to diagnose transplant complications. A micromolecular 'tubular' proteinuria (mw 70-10,000) was found in all post-operative urines. Later on during clinically normal periods the patients exhibited an unphysiological proteinuria of mw 70-40,000. Recurrence of tubular proteinuria was associated with rejection episodes and acute kidney failure. Twelve patients developed a macromolecular glomerular proteinuria (mw greater than 60,000), caused by recurrent glomerulonephritis, glomerular rejection disease or renal vein thrombosis. Steroid treatment reduced the glomerular permeability for macromolecules above mw 65,000.