Platelet satellitism--an ultrastructural study.

Ultrastructural studies by scanning and transmission electron microscopy were carried out on one of four cases of platelet satellitism. Adherence to the neutrophils was mainly by focal contact between small surface projections of the platelets and neutrophils. Phagocytosis was not seen with the neutrophils but was evident in the monocytes. The degree of satellitism noted increased with the time the blood anticoagulated with EDTA was left at room temperature. Mixing experiments with a patient's plasma and control cells and the patient's cells and control plasma were inconclusive but suggested that the abnormality may reside in the plasma.