Inhibitor to factor VIII in a non-haemophilic patient: evaluation of the response to DDAVP and the in vitro kinetics of factor VIII. A case report.

We report a case of inhibitor to factor VIII in a non-haemophilic patient. Immunosuppressive therapy with azathioprine was started, but without any advantage. Evaluation of the kinetics of exogenous factor VIII in vitro showed a rapid but incomplete neutralization of factor VIII. Following s.c. 1-deamino-8-D-arginine vasopressin (DDAVP) administration, a large and prolonged increase in factor VIII:C and von Willebrand factor antigen occurred together with complete inhibitor saturation. Therefore DDAVP may represent an important tool in the management of the bleeding episodes in these patients and evaluation of its suitability in the management of these patients should be carried out.