title: Elevated platelet-associated IgG in the thrombocytopenia of septicemia.
abstract: The mechanism of thrombocytopenia, a frequent complication of septicemia, is obscure, but indirect evidence suggests that the immune system may be involved. To investigate this possibility, we quantitated platelet-associated IgG on platelets obtained from 44 patients during 46 episodes of septicemia. Thrombocytopenia occurred in 21 of 46 episodes (46 per cent). Platelet-associated IgG was elevated in eight of 11 episodes of gram-negative septicemia and thrombocytopenia (47.3 +/- 11.7 fg of IgG per platelet [mean +/- S.E.]) and in one of 20 patients with gram-negative septicemia and normal platelet counts (5.9 +/- 1.1) (P less than 0.001). Elevated levels occurred in eight of 10 patients with gram-positive septicemia and thrombocytopenia (55.3 +/- 14.7 fg of IgG per platelet) and in none of 11 patients with gram-positive septicemia and normal platelet counts (5.6 +/- 1.7) (P less than 0.001). Serial testing during the thrombocytopenia and recovery showed an inverse relation between the platelet count and platelet-associated IgG. Thrombocytopenia in some patients with septicemia may be related to the binding of IgG to platelets.
mesh_terms: D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex; D001666:Binding Sites, Antibody; D001772:Blood Cell Count; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D018805:Sepsis / Q000097:blood* / Q000150:complications; D013921:Thrombocytopenia / Q000209:etiology / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G