Platelet satellitosis to polymorphonuclears: cytochemical, immunological, and ultrastructural characterization of eight cases.

Satellitosis of platelets to polymorphonuclears was observed in eight patients. This phenomenon occurred only in blood anticoagulated by EDTA at room temperature. In vivo and in vitro platelet and neutrophil function were normal. Electron microscopy studies showed normal structures in both cells but demonstrated platelet phagocytosis by neutrophils. In all cases we were able to transfer the platelet satellitosis factor by mixing platelet plasma (or serum) with whole blood from ABO compatible healthy controls; conversely, when the same plasma (or serum) was pre-incubated with anti-IgG serum, satellitosis to normal blood was not observed. While this finding suggests that a plasmatic protein with the properties of an IgG immunoglobulin was probably responsible for the phenomenon, we were unable to correlate it with the clinical condition of the patient, functional abnormalities of the blood components, or drugs.