title: Autoantibodies against platelet glycoproteins in critically ill patients with thrombocytopenia.
abstract: OBJECTIVE
  The aim of the study was to investigate immunologic causes of thrombocytopenia in critically ill patients, especially causes that were related to platelet-associated IgG antibodies.
  
  
  METHODS
  All patients admitted to two intensive care units between May 1 and October 30, 1997, who developed thrombocytopenia (less than 100 x 10(9) platelets/L) were studied prospectively. We measured platelet-associated IgG with a radioimmunoassay using I(125)-labeled polyclonal antihuman IgG. Characterization of platelet-associated IgG was assessed with a monoclonal antibody immobilization of platelet antigen. Circulating immune complexes were also assayed.
  
  
  RESULTS
  Of the 61 patients with thrombocytopenia, elevated platelet-associated IgG was found in 18 (30%). Associated antiplatelet autoantibodies (glycoprotein IIb/IIIa) were detected in 4 patients, circulating autoantibodies (glycoprotein Ib/IX) were detected in sera from 2 patients, and circulating immune complexes were detected in 3 patients. The nature of the platelet-associated IgG could not be determined in 10 patients. Elevated platelet-associated IgG was associated with sepsis and previous cardiopulmonary bypass. Thrombocytopenic patients with elevated platelet-associated IgG had a lower nadir platelet count (58 +/- 27 x 10(9)/L vs 74 +/- 24 x 10(9)/L, P = 0.03).
  
  
  CONCLUSIONS
  Elevated platelet-associated IgG, some of which are platelet autoantibodies, is frequent in thrombocytopenic patients with sepsis or after cardiopulmonary bypass.
authors.affiliation: Service d'Anesthésie-Réanimation Chirurgicale, AP-HP Hôpital Tenon, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Stéphan
authors.forename: M A
authors.initials: MA
authors.lastname: Cheffi
authors.forename: C
authors.initials: C
authors.lastname: Kaplan
authors.forename: J
authors.initials: J
authors.lastname: Maillet
authors.forename: A
authors.initials: A
authors.lastname: Novara
authors.forename: J
authors.initials: J
authors.lastname: Fagon
authors.forename: F
authors.initials: F
authors.lastname: Bonnet
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D001323:Autoantibodies / Q000097:blood*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D016638:Critical Illness; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D011863:Radioimmunoassay; D012307:Risk Factors; D018805:Sepsis / Q000276:immunology; D013921:Thrombocytopenia / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D007074:Immunoglobulin G; D010980:Platelet Membrane Glycoproteins