Pseudothrombocytopenia: An Immunologic Study on Platelet Antibodies Dependent on Ethylene Diamine Tetra-Acetate

• Published in: Blood Vol. 59; no. 1; pp. 157 - 161
• Main Authors: Pegels, J.G., Bruynes, E.C.E., Engelfriet, C.P., Borne, A.E.G.Kr. von dem
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.1982
• Subjects: Antibodies - analysis; Antibodies - immunology; Blood Platelets - immunology; Edetic Acid - pharmacology; Fluorescent Antibody Technique; Humans; Immunoglobulin Fab Fragments - immunology; Thrombocytopenia - immunology
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V59.1.157.157

Antibodies specifically reacting with platelets only in the presence of EDTA, by the platelet immunofluorescence test, were found in the serum of 20 patients with pseudothrombocytopenia due to in vitro EDTA-dependent platelet agglutination. These antibodies reacted optimally at 0–4°C. In 19 patients, IgG antibodies were detected; in 8 patients, IgM or IgA antibodies were also found. In one patient, only IgM antibodies were found. In 14 patients, the IgG antibodies were lgG1, but lgG2, lgG3, and lgG4 antibodies were also seen in 7 patients. The reaction of platelets with the antibodies was detectable in the presence of Na2EDTA, the K, Ca, and Mg salts of EDTA, and K2EGTA. F(ab‘)2 or F(ab‘) fragments of the IgG antibodies reacted as strongly as the intact antibodies, indicating that the reaction is dependent on the antibody-combining site. The EDTA-dependent antibodies did not show platelet-group specificity. However, platelets from patients with Glanzmann disease did not react with the antibodies.