Fragments of urinary fibrin/fibrinogen degradation products and cross-linked fibrin degradation products in various renal diseases.

In children with several kinds of glomerular disease, fragments of fibrin/fibrinogen degradation products (FDP) and cross-linked fibrin degradation products (XLFDP) in the urine were investigated by autoradiography using western blotting method. Results were compared with selectivity of proteins observed in cases of proteinuria, or with histological findings. Patients with nephrotic syndrome exhibited slightly increased amount of urinary FDP, consisted mainly of X and Y fragments. On the other hand, in cases of proliferative glomerulonephritis, such as acute glomerulonephritis, purpura nephritis, Ig A nephropathy, systemic lupus erythematosus, or hemolytic uremic syndrome, increased FDP, including XLFDP, was detected in the urine. In these cases, FDP was consisted mainly of fragments X, Y, and D-dimer, and could not be correlated with the degree of mesangial proliferation or with urinary protein selectivity. It was concluded that the increased urinary FDP and XLFDP were derived not only from filtration of plasma fibrinogen or FDP, but also from fibrinolysis of intraglomerular fibrin deposits.