title: The human platelet receptor(s) for quinine/quinidine-dependent antibodies.
abstract: Substantial evidence now exists to associate platelet membrane glycoprotein Ib (GP Ib) with a receptor for quinine/quinidine-dependent platelet-specific antibodies. A direct relationship between GP Ib and this receptor activity has been difficult to establish for several reasons, including: the apparent existence of additional receptor activity not directly attributable to the presence of GP Ib; the variable reactivity of different sera observed by some investigators; the instability of receptor activity in semi-purified, soluble form; and differences in methods used by various laboratories to identify and quantitate either quinine/quinidine-dependent antibodies or platelet receptor activity. Moreover, little attention has been paid to the possibility that the Bernard-Soulier syndrome may represent a more heterogeneous collection of functional and molecular platelet abnormalities than hitherto supposed. As more patients are identified and studied, this possibility can also be addressed. A role for factor VIII-related antigen (VIIIR:Ag) in platelet destruction and/or clearance by drug-antibody complexes remains controversial. The observation that VIIIR:Ag is required for platelet activation in vitro (serotonin release, aggregation and increased platelet factor 3 availability) has been made, yet recent evidence indicates that VIIIR:Ag is not required for binding of antibody to platelets in the presence of drug or for complement-mediated lysis of platelets by antibody and drug. Evidence that VIIIR:Ag participates as part of the initial immunogenic complex is intriguing, yet still unconfirmed.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000906:Antibodies / Q000302:isolation & purification*; D000941:Antigens / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000276:immunology; D005169:Factor VIII / Q000276:immunology; D006023:Glycoproteins / Q000302:isolation & purification; D006801:Humans; D007105:Immune Complex Diseases / Q000139:chemically induced; D008565:Membrane Proteins / Q000302:isolation & purification; D019038:Platelet Glycoprotein GPIb-IX Complex; D010980:Platelet Membrane Glycoproteins; D011802:Quinidine / Q000009:adverse effects / Q000276:immunology*; D011803:Quinine / Q000009:adverse effects / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000302:isolation & purification; D011971:Receptors, Immunologic / Q000302:isolation & purification*; D013921:Thrombocytopenia / Q000139:chemically induced; D014841:von Willebrand Factor
chemical_list: D000906:Antibodies; D000941:Antigens; D006023:Glycoproteins; D008565:Membrane Proteins; D019038:Platelet Glycoprotein GPIb-IX Complex; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C032193:glycoprotein receptor GPIb-IX; D014841:von Willebrand Factor; D005169:Factor VIII; D011803:Quinine; D011802:Quinidine