A new type of pseudothrombocytopenia: EDTA-mediated agglutination of platelets bearing Fab fragments of a chimaeric antibody.
In vitro agglutination of platelets leading to low automated platelet counts was observed in EDTA-anticoagulated blood from human volunteers receiving infusions of Fab fragments of a chimaeric monoclonal antibody to platelet glycoprotein IIb-IIIa. This pseudothrombocytopenia depended on the presence of chimaeric Fab on the platelet surface and was not seen when sodium citrate was used as anticoagulent. Preliminary evidence suggests that this phenomenon might be mediated by immunoglobulin G reactive with the human component of the chimaeric Fab. It is important to exclude pseudothrombocytopenia when low automated platelet counts are reported in association with the administration of chimaeric anti-platelet antibodies.
Christopoulos
C G
CG
Department of Haematology, University College London.
Machin
S J
SJ
D001792:Blood Platelets / Q000276:immunology*; D004492:Edetic Acid / Q000494:pharmacology*; D005434:Flow Cytometry; D006384:Hemagglutination / Q000187:drug effects; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D010976:Platelet Count; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013921:Thrombocytopenia / Q000097:blood* / Q000175:diagnosis / Q000276:immunology
D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D010980:Platelet Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D004492:Edetic Acid