EDTA-dependent platelet phagocytosis - A cytochemical, ultrastructural, and functional characterization

Platelet satellitosis of polymorphonuclear cells is a phenomenon induced or enhanced by the anticoagulant EDTA. In contrast with previously reported s tudies, the subject in the present case did nor demonstrate platelet satell itism but was profoundly pseudothrombocytopenic owing to platelet phagocyto sis. Virtually all polymorphonuclear leukocytes and monocytes contained num erous ingested platelets in contrast with previous cases in which phagocyto sis was observed only rarely and involved ingestion of single cells. The ph enomenon was documented by immunocytochemical staining and transmission ele ctron microscopy. Autoantibodies were detected in EDTA-anticoagulated blood . However neither platelet antibody nor phagocytosis was present when hepar in, acid-citrate dextrose, or citrate was used as an alternative anticoagul ant. The antibody was not temperature dependent. Mixing studies showed the transfer of the phagocytosis phenomenon to healthy donors. Although platele t function assays are typically normal in EDTA-dependent platelet satelliti sm, this subject showed no secondary aggregation wave in response to adenos ine diphosphate and depressed adenosine triphosphate release with collagen, adenosine diphosphate, and arachidonic acid.