Plasminogen and antithrombin III deficiencies in the childhood nephrotic syndrome associated with plasminogenuria and antithrombinuria.

Three of four patients with the childhood nephrotic syndrome were found to have low plasma plasminogen concentrations; all four had low plasma antithrombin III concentrations. In the two patients who were tested, urinary concentrations of these proteins exceeded the plasma concentrations. As the urinary losses of plasminogen and antithrombin III decreased over the course of illness, the plasma concentrations of antithrombin III and plasminogen rose. One patient had multiple thromboembolic episodes. We conclude the deficiencies of antithrombin III and plasminogen, probably secondary to urinary excretion of these proteins, may contribute to the thrombotic diathesis associated with nephrotic syndrome.