Thrombocytopenia Associated With Pregnancy in a Patient With Type IIB von Willebrand’s Disease

• Published in: Blood Vol. 69; no. 3; pp. 786 - 789
• Main Authors: Rick, Margaret E., Williams, Sybil B., Sacher, Ronald A., McKeown, Laurie P.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01-03-1987; The Americain Society of Hematology
• Subjects: Adult; Aspirin - pharmacology; Biological and medical sciences; Blood Coagulation Tests; Bucladesine - pharmacology; Epoprostenol - pharmacology; Female; Hematologic and hematopoietic diseases; Humans; Medical sciences; Platelet Aggregation - drug effects; Platelet diseases and coagulopathies; Pregnancy; Pregnancy Complications, Hematologic - blood; Pregnancy Complications, Hematologic - etiology; Ristocetin - pharmacology; Thrombocytopenia - blood; Thrombocytopenia - etiology; von Willebrand Diseases - classification; von Willebrand Diseases - complications; Pregnancy; Thrombocytopenia; Platelet; Hemopathy; Willebrand disease
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V69.3.786.786

Thrombocytopenia may accompany variant (type IIB) von Willebrand's disease (vWD) and is thought to result from binding of the abnormal von Willebrand factor (vWF) to the patient's platelets with subsequent platelet aggregate formation and clearance. We have studied a patient with type IIB vWD who became thrombocytopenic during two pregnancies. During the third trimester of pregnancy, her platelet counts dropped to 20,000 to 30,000/µL, and an increase in the intermediate-sized vWF multimers was seen on agarose gel electrophoresis. During this time her platelet-rich plasma showed spontaneous platelet aggregation, and her plasma caused spontaneous aggregation of normal washed platelets. Antibody to platelet glycoprotein lb completely blocked the spontaneous platelet aggrega- tion, while antibody to platelet glycoprotein lIb/IIIa did not block the response at the concentrations used. Inhibitors of platelet function that elevate platelet cyclic AMP also blocked the response, but aspirin had no effect on the spontaneous platelet aggregation. The patient illustrates that the platelet counts in one individual can vary greatly in type IIB vWD and that the thrombocytopenia that occurs can appear under physiologic conditions that stimulate the endogenous production of the patient's abnormal vWF. The mechanisms leading to spontaneous platelet aggregation and thrombocytopenia appear to be similar to those described for other patients with type IIB vWD. © 1987 by Grune & Stratton. Inc.