title: Acquired thrombasthenia due to inhibitory effect of glycoprotein IIbIIIa autoantibodies.
abstract: BACKGROUND
  A 75 year old patient presenting with mucocutaneous bleeding was diagnosed with acquired thrombasthenia. The diagnosis was based on lack of platelet aggregation with adenosine diphosphate (ADP), arachidonic acid and collagen, and normal aggregation induced by ristocetin.
  
  
  OBJECTIVE
  To study the mechanism of platelet function inhibition in a patient with acquired thrombasthenia.
  
  
  METHODS
  Aggregation assays of platelets from the patient and healthy controls were performed. In addition, anti-glycoprotein (GP) IIbIIIa antibodies bindingto normal in the presence or absence of the patient's serum was by flow cytometry.
  
  
  RESULTS
  Aggregation of normal platelets in the presence of patient's plasma was inhibited four- and 2.5-fold in the presence of ADP and arachidonic acid respectively, while collagen-induced aggregation was completely abolished. Ristocetin-induced aggregation was normal. The patient's serum inhibited binding of commercial anti-glycoprotein IIbIIIa antibodies to normal platelets twofold by flow cytometry. Treatment with anti-CD20 monoclonal antibody (rituximab) normalized the patient's platelet aggregation.
  
  
  CONCLUSIONS
  These results suggest that the patient developed inhibitory anti-GPIIbIIIa autoantibodies that caused acquired thrombasthenia.
authors: Dorit
authors: D
authors: Blickstein
authors: Rima
authors: R
authors: Dardik
authors: Esther
authors: E
authors: Rosenthal
authors: Judith
authors: J
authors: Lahav
authors: Yair
authors: Y
authors: Molad
authors: Aida
authors: A
authors: Inbal
mesh_terms: D000244:Adenosine Diphosphate; D000368:Aged; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D016718:Arachidonic Acid; D001323:Autoantibodies / Q000032:analysis*; D001791:Blood Platelet Disorders / Q000175:diagnosis / Q000209:etiology / Q000276:immunology; D003094:Collagen; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology; D010974:Platelet Aggregation / Q000187:drug effects / Q000276:immunology; D010979:Platelet Function Tests / Q000379:methods*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology*; D012074:Remission Induction; D012310:Ristocetin; D000069283:Rituximab; D016896:Treatment Outcome
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D001323:Autoantibodies; D007155:Immunologic Factors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D012310:Ristocetin; D016718:Arachidonic Acid; D000069283:Rituximab; D000244:Adenosine Diphosphate; D003094:Collagen