No abstract

Platelet satellitism, an in vitro phenomenon of platelet rosetting around polymorphonuclear neutrophils, is observed exclusively in blood treated with EDTA as an anticoagulant at room temperature. Neither heparin nor citrate produces rosetting. The proposed mechanisms include immunologic bonding through EDTA-dependent antiplatelet and antineutrophil IgG autoantibodies directed against the glycoprotein IIb/IIIa complex and Fc g receptors of platelets and neutrophils, respectively, and nonimmunologic adherence mediated by thrombospondin or the alpha-granule protein of other platelets. The results of both in vivo and in vitro platelet-function tests are normal. Phagocytosis of platelets by polymorphonuclear leukocytes and monocytes is sometimes seen. Severe platelet satellitism is an important cause of spurious thrombocytopenia.