Analysis of urinary and circulating FDP subfragments and subunits: application of the western-blot technique

We applied the Western-blot technique for qualifying fibrin/fibrinogen degradation products (FDP) subfragments and subunits. With this technique we examined urine or serum samples from patients with glomerulonephritis and disseminated intravascular coagulation (DIC), in order to observe how primary or secondary fibrinolysis functioned under these pathological conditions. We also tested the antigenic recognition of several FDP antibodies with this technique. The results obtained were as follows: 1) FDP in serum samples from patients with DIC consisted of both fibrinogenolytic and fibrinolytic products; 2) Fibrinolysis was predominant in the serum from one patient with Henoch-Schönlein purpura nephritis, and its level increased after fibrinolytic therapy with urokinase; 3) Fibrinogen and fibrin polymers were always the major components of urinary FDP, although fibrinolytic products such as subfragment D-D dimer were detected in patients with glomerular disease and increased in acute exacerbation; 4) Anti-FDP D-D dimer monoclonal antibody (DD 3B6), which is usually considered to react specifically with cross-linked fibrin derivatives, also seemed to have cross-reactivity with non-crosslinked fibrin derivatives.