Combined defect in membrane expression and activation of platelet GPIIb--IIIa complex without primary sequence abnormalities in myeloproliferative disease

Br J Haematol. 2000 Dec;111(3):954-64.

Abstract

Defects in glycoprotein (GP)IIb-IIIa or in its activation may cause abnormal platelet aggregation and a bleeding diathesis. We report studies in a 67-year-old man with a myeloproliferative disease and markedly abnormal platelet responses. By flow cytometry, platelet binding of two complex-specific anti-GPIIb-IIIa monoclonal antibodies (mAbs), A2A9 and 10E5, was approximately 50% of normal. An enzyme-linked immunosorbent assay (ELISA) using immobilized kistrin showed 18% of normal membrane GPIIb-IIIa complex. By immunoblot analysis, GPIIb and GPIIIa levels in platelet lysates and membranes were near normal. Activation of GPIIb-IIIa, monitored with mAb PAC-1, was markedly decreased (< 20% of normal) in response to ADP, thrombin and platelet-activating factor (PAF); expression of ligand-induced binding sites (LIBS) was < or = 30% of normal. Signal transduction-independent LIBS expression, induced by echistatin, was approximately 60% of normal, suggesting that the integrin present had intact ligand-binding capability. Sequence analysis of GPIIb and GPIIIa cDNA, and platelet mRNA levels for both subunits, were normal. These findings document an acquired combined defect in membrane expression (secondary to a defect in post-translational processing of the complex) and inside-out signalling-dependent activation of the GPIIb-IIIa complex.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / pharmacology
  • Adenosine Diphosphate / pharmacology
  • Aged
  • Antibodies, Monoclonal / metabolism
  • Binding Sites
  • Blood Platelets / metabolism*
  • Calcimycin / pharmacology
  • DNA, Complementary / genetics
  • Diglycerides / pharmacology
  • Enzyme Activators / pharmacology
  • Flow Cytometry
  • Humans
  • Immunoblotting
  • Intercellular Signaling Peptides and Proteins
  • Ionophores / pharmacology
  • Macrophage-1 Antigen / analysis
  • Male
  • Myeloproliferative Disorders / blood*
  • Myeloproliferative Disorders / immunology
  • Neutrophils / immunology
  • Peptides / pharmacology
  • Platelet Activating Factor / pharmacology
  • Platelet Aggregation
  • Platelet Aggregation Inhibitors / pharmacology
  • Platelet Glycoprotein GPIIb-IIIa Complex / analysis
  • Platelet Glycoprotein GPIIb-IIIa Complex / metabolism*
  • Polymerase Chain Reaction
  • Protein Binding
  • Protein Kinase C / metabolism
  • RNA, Messenger / analysis
  • Receptors, Thrombin / metabolism
  • Sequence Analysis, DNA
  • Serotonin / metabolism
  • Signal Transduction*

Substances

  • Antibodies, Monoclonal
  • DNA, Complementary
  • Diglycerides
  • Enzyme Activators
  • Intercellular Signaling Peptides and Proteins
  • Ionophores
  • Macrophage-1 Antigen
  • Peptides
  • Platelet Activating Factor
  • Platelet Aggregation Inhibitors
  • Platelet Glycoprotein GPIIb-IIIa Complex
  • RNA, Messenger
  • Receptors, Thrombin
  • 1,2-dioctanoylglycerol
  • echistatin
  • Serotonin
  • Calcimycin
  • Adenosine Diphosphate
  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
  • Protein Kinase C