IMPROVED DEXTRAN PREPARATION OF HUMAN-LEUKOCYTES FOR CHEMILUMINESCENCE ANALYSIS OF THE OXIDATIVE BURST OF POLYMORPHONUCLEAR CELLS

An improved method for the preparation of leucocyte-rich plasma from h uman blood samples for chemiluminescence (CL) analysis is described. H eparinized blood is layered over 4% dextran in a ratio of 1:1 (v/v). T he leucocyte-rich plasma is obtained after a 1 h sedimentation of the erythrocytes. When compared with the plasma obtained by the usual meth od of mixing blood with dextran, the residual red cell count was reduc ed. On the other hand, the index of phagocytosis (peak values of activ ated phagocytosis/spontaneous phagocytosis) was increased. This is cau sed by increased spontaneous CL activity after mixing blood with dextr an, which can activate leucocytes. Such activation was observed both i n plasma samples and in whole blood samples when measured immediately after dextran addition or after 1 h incubation with dextran.