Significance of urinary fibrin/fibrinogen degradation products (FDP) measured by highly sensitive ELISA method in various renal diseases

Abstract

In order to clarify the abnormalities of intra-glomerular coagulation and fibrinolysis in patients with various renal diseases, urinary fibrin/fibrinogen degradation products (FDP) have been examined by several methods. We established a highly sensitive new method of enzyme-linked immunosorbent assay for urinary FDP. The results were as follow: 1) The mean +/- SD of urinary FDP in normal subjects was 10.30 +/- 9.08ng/ml. 2) The urinary FDP levels in chronic glomerulonephritis, nephrotic syndrome and chronic renal failure patients were significantly higher than normal subjects, and the levels in SLE, Alport's syndrome patients were higher than normal subjects. 3) The urinary FDP levels were a little bit higher in the patients with proliferative glomerulonephritis than in chronic glomerulonephritis patients with minor lesion or membranous nephropathy. 4) There was significant correlation between urinary FDP and urinary protein in chronic glomerulonephritis, while there was no correlation in nephrotic syndrome. 5) There was no correlation between urinary FDP and intra-glomerular fibrin deposits examined by immunofluorescent study in chronic glomerulonephritis, while in nephrotic syndrome, there were high levels of urinary FDP in the positive fibrin deposits cases. These results suggested that the most of the part of excretion of the urinary FDP in chronic glomerulonephritis is associated with the filtration of blood FDP to urine through the glomerular basement membrane, while in the nephrotic syndrome cases the origin of urinary FDP is related to the filtration and/or the intra-glomerular coagulation abnormalities.