Characteristics of the specific removal of lymphocytes and granulocytes from whole blood in an automated bottom-and-top processing system

Characteristics of lymphocyte and granulocyte removal were studied during p rocessing of fresh and overnight-stored human blood in a bottom-and-top sem iautomated system using the buffy coat (BC) technique. Blood cells were cou nted in the resulting components. Removal efficiency of lymphocytes and gra nulocytes correlated with the loss of erythrocytes due to removal of the BC . Sigmoidal curves showed a good fit to experimental data. Variables of the equations differed substantially concerning removal of lymphocytes and gra nulocytes. Overnight storage of blood at 20-22 degreesC prior to processing resulted in changes in efficiency of leukocyte removal. Removal of lymphoc ytes decreased, while that of granulocytes increased due to overnight proce ssing. Lymphocytes may be removed almost quantitatively with less than 10% (fresh blood) or 15% (overnight-stored blood) loss in erythrocyte content o f the donated blood, corresponding to less than 28 ml packed red cells in t he BC. Granulocytes seem to represent the residual amount of the final leuk ocyte content in the erythrocyte product. The present study may contribute to the production of erythrocyte products with fewer contaminating leukocyt es and to the standardizing of semiautomated blood processing.