AN ACQUIRED HEMORRHAGIC DISORDER OF FIBRIN CROSS-LINKING DUE TO IGG ANTIBODIES TO FXIII, SUCCESSFULLY TREATED WITH FXIII REPLACEMENT AND CYCLOPHOSPHAMIDE

We report a new case of severe bleeding diathesis due to an acquired i nhibitor of fibrin crosslinking. The patient, an 80-year-old woman, wa s admitted to the hospital for a massive subcutaneous hematoma, with s evere anemia requiring red cell transfusion; a subsequent retroperiton eal hematoma developed 2 weeks later. Coagulation studies were normal except for a thromboelastographic pattern suggestive of FXIII deficien cy. Clot solubility test was abnormal even after 1:1 mix with normal p lasma. Immunochemical studies confirmed the presence of a monoclonal I gG lambda inhibitor directed against FXIII activity (type II FXIII inh ibitor). The patient IgG fraction selectively inhibited FXIII transami dating activity but did not inhibit the thrombin-mediated activation o f FXIII. The patient was treated with high doses of FXIII concentrate to overcome the inhibitor and immunosuppressive therapy with cyclophos phamide and discharged in good conditions. High doses of commercially available FXIII appear to be a safe and effective method of controllin g acute episodes of bleeding in patients with acquired FXIII deficienc y. (C) 1995 Wiley-Liss, Inc.