An improved method for isolating viable human leukocytes from peripheral blood.

By JOSEPH H. LAPIN, ANDREW HORONIcK AND ROBERT H. LAPIN T HE COMPLETE SEPARATION of viable leumkocytes from the erythrocytes of peripheral human blood, in a manner satisfactory for immunologic procedures, has never been achieved. As a consequence, all of the work on agglutination phenomena and the demonstration of ABO group antigens in leukocytesl*3 becomes subject to criticism. Riis4 described the use of Dextran to obtain cell suspensions containing equal numbers of red and white cells which he used in a direct agglutination procedure to demonstrate leukocyte antigens. Bakemeir and Swisher6 recently modified this technic to eliminate Dextran from the final leukocyte suspension. They found nonspecific clumping of leukocytes by anti-sera which did not agglutinate the erythrocytes of the white cell donor. Certain of these leukocyte clumps were demonstrated to be due to ghosts of erythrocytes reacting with the antibody present. They concluded that their observations “indicate that certain results of leuko-agglutination techniques, which have been interpreted as demonstrating the presence of A and B antigens on human leukocytes deserve re-evaiuatioml, and empilasize tile importance of developing methods of preparing homogenous leukocyte suspensions.” With the method to be described, leukocyte suspensions can be prepared in which the ratio of erythrocytes to leukocytes is considerably less than that obtained with previously described technics.