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Joseph Sweeney, Andrew Heaton he presence of allogeneic leukocytes in blood products received little T attention until the mid-1950s when these "passenger" cells were im plicated in the etiology of febrile transfusion reactions, and early strate gies based on centrifugation were developed to effect their removal. In recent decades and, particularly in the past five years, there has been an accumulation of literature implicating leukocytes in a wide variety of undesirable reactions to blood transfusion. White cells are the least numerous of the cellular elements in blood and ratios of white cells to platelets and white cells to red cells are ap proximately 1:15 to 1:1000 respectively. This ratio is maintained in whole blood, but may be altered slightly in the process of component prepara tion. Any production or processing step which intentionally decreases this ratio will result in a product which can be described as white cell depleted. It has, however, become more common to define the outcome as a residual white cell content, rather than a decrease in cellular ratios, although the latter makes more sense on theoretical grounds, since deple tion of white cells needs to be put in the context of any unintentional loss of red cells or platelets. The end result of this intentional processing step, therefore, is generally expressed as the residual absolute number of white cells or as the degree of difference in white cell content, the latter expressed as either a percentage change or as a logarithmic reduction.
List of contents
1. Introduction.- 2. Methods of Leukodepletion.- 3. Enumeration of Low White Cells.- 4. Mechanisms of Leukodepletion by Filtration.- 5. Role of Contaminating White Blood Cells in the Storage Lesions of Red Cells and Platelets.- 6. Leukodepletion to Prevent Transfusion Reactions: Effects on Cytokines and Other Biologic Response Modifiers.- 7. Leukodepletion and Alloimmunization.- 8. Role of Donor Leukocytes and Leukodepletion in Transfusion-Associated Viral Infections.- 9. Leukocyte Depletion and Transfusion-Induced Immunomodulation.- 10. The Role of Leukocyte Depletion in Prevention of Transfusion-Related Acute Lung Injury.- 11. The Role of Leukocyte Depletion in the Prevention of Reperfusion Injury Associated with Open Heart Surgery.- 12. The Use of Leukodepleted Blood Components for Neonates and Infants.- 13. Leukocyte Depleted Blood Transfusion in Hematopoietic Stem Cell Reconstitution Therapy.- 14. Cost-Effectiveness of Leukodepletion.
Summary
White cells are the least numerous of the cellular elements in blood and ratios of white cells to platelets and white cells to red cells are ap proximately 1:15 to 1:1000 respectively.
