The role of antiplatelet autoantibody assays in the diagnosis of immune thrombocytopenic purpura.
Immune thrombocytopenic purpura (ITP) is a disorder almost always manifested by antibody-induced thrombocytopenia. In 1987, two clinically useful antigen-specific assays were reported, the immunobead assay and the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay. These two assays and their variations give similar results and can measure both platelet-associated and plasma antibodies. Three prospective studies have reported assay results with sensitivities ranging from 49% to 66% and specificities ranging from 78% to 93%. Most antibodies react with either platelet glycoprotein (GP) IIb/IIIa or GPIb/IX. Recent evidence suggests that antiplatelet antibody assays may also be useful in predicting disease prognosis. Rare ITP patients have bleeding with normal or near-normal platelet counts, a prolonged bleeding time, and aggregation abnormalities due to autoantibodies that affect platelet function. Incubation of patient plasma, IgG or eluate with normal platelet-rich plasma reproduces the patient's aggregation abnormalities.
McMillan
Robert
R
Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM 215, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. mac.mcmillan@att.net
D000328:Adult; D016824:Antigens, Human Platelet; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001324:Autoantigens / Q000097:blood; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006801:Humans; D007159:Immunologic Tests; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011696:Purpura, Thrombocytopenic / Q000175:diagnosis* / Q000276:immunology; D016553:Purpura, Thrombocytopenic, Idiopathic
D016824:Antigens, Human Platelet; D001323:Autoantibodies; D001324:Autoantigens