Pseudo - Bernard - Soulier Syndrome : Thrombocytopenia Caused by Autoantibody to Platelet Glycoprotein lb

The Bernard-Soulier syndrome is an inherited bleeding disorder that is due to a deficiency in platelet glycoprotein lb. Bernard-Soulier platelets fail to agglutinate in response to ristocetin despite normal levels of factor Vlll:von Willebrand factor. We report a patient who developed severe refractory thrombocytopenia postsurgically while receiving procainamide therapy. Thrombocytopenia was immune mediated since the patient’s platelets bore high levels of antiplatelet antibody. Radioimmunoprecipitation studies platelet glycoproteins lb and V as well as platelet HLA. The patient’s plasma as well as purified immunoglobulin G completely inhibited the ristocetin-induced aggregation of normal platelets but did not inhibit adenosine diphosphateinduced aggregation. The laboratory studies revealed that this patient suffered from antibody-mediated thrombocytopenia with unusual characteristics that we have called pseudo-Bernard-Soulier syndrome. © 1987 by Grune & Stratton, Inc. demonstrated that the autoantibodies had specificity for