Urinary Fibrinogen and Fibrin Fragments in Children with Renal Disease

Fibrinogen fragments (X, Y, D and E) and fibrin fragments (D-dimer and E) were examined in the urine of 52 patients with various types of renal diseases. One or more of the fibrinogen fragments were detectable in all the urine specimens. D-Dimer together with fibrinogen fragments was found in 38 of the 52 patients. The clearance ratio of D-dimer to IgG, which indicates D-dimer generated in the kidney, was lower than 1 in all the patients with the minimal changes nephrotic syndrome, and was greater than 1 in the majority of patients with acute glomerulonephritis, rapidly progressive glomerulonephritis, mesangial proliferative glomerulonephritis and membranoproliferative glomerulonephritis. Our results suggest that urinary fibrin/fibrinogen degradation products (FDP) in renal diseases are derived primarily from increased filtration of FDP from the plasma through a damaged glomerular basement membrane, and that the mechanism of lysis of cross-linked fibrin deposited in the glomeruli occurs simultaneously in some types of glomerulonephritis. It seems that the determination of the clearance ratio of D-dimer to IgG may be useful in assessing the activation of the coagulation and fibrinolysis systems in the kidney in patients with renal diseases.