A measurement technique for cell adhesiveness

Determination of the percentage of cells in clumps on a stained smear of human peripheral blood porvided a useful, accurate technique for measuring cell adhesiveness. Smears of human peripheral blood drawn with EDTA were prepared on a blood slide centrifuge, stained, and examined under a light microscope. Statistical analysis showed that the method resulted in a Poisson distribution of particles on the slide, where a particle was considered to be a simple cell, or two or more cells which appeared to be touching, Analysis of the distributions of erythrocytes and leukocytes showed that clumps were formed before the cells were deposited on the slide. When adhesiveness of erythrocytes or leukocytes was increased by incubation with antiserum to the corresponding cell type, the percentage of that cell type in clumps increased proportionately, Preliminary results using the method showed that normal human donors had similar to 1% of their erythrocytes and 1- 5% of their leukocytes in clumps. In chronic myelocytic leukemia, as many as 60% of the leukocytes were in clumps.