Retention in glass bead columns as a measure of leucocyte adhesiveness. II. Influence of platelets and erythrocytes.

The influence of platelets and erythrocytes on the retention of leucocytes in glass bead columns was studied. Leucocyte retention increased when platelet retention was stimulated by the presence of erythrocytes. In the presence of only a few erythrocytes, platelet retention was low, and platelets did not influence leucocyte retention. When only a small number of platelets was present, erythrocytes inhibited leucocyte retention. The platelet-dependent leucocyte retention increased as the volume passed through the columns was increased. However, the platelet-independent leucocyte retention did not change when the sample size was increased. In blood from patient with thrombocytopenia or defect in platelet function and in normal blood treated with inhibitor of platelet adhesion, neutrophil retention was reduced. However, erythrocyte-free leucocyte suspensions from these cases showed normal leucocyte retention. Thus, experiments with whole blood may serve as a model for the study of platelet-leucocyte interaction. However, for the study of leucocyte adhesiveness per se, isolated leucocytes seem more suitable than whole blood.