[Formation of "Rosettes" induced by polyethylene glycol]

Human blood cells were washed and treated by PEG 6 000 (40% solution in BME) at 37 degrees for 15 min. A strong agglutination was observed. After dilution with 3 vol. of BME and shaking, microscopic examination at low magnification revealed small aggregates disseminated in dispersed population of erythrocytes. These aggregates were shown to be formed by a polymorphonuclear cell closely surrounded by erythrocytes. The possible explanation of the formation of such "Rosettes" was briefly discussed.