Leukocyte depletion of cellular blood components.

Clinical studies have indicated that the use of leukocyte-reduced cellular blood components produced in the laboratory may prevent febrile reactions and delay or prevent alloimmunization to HLA antigens and refractoriness to platelet transfusion. Additional investigations regarding the effects of the use of leukocyte-reduced blood components were reported during the past year. A recent study in patients with hematologic malignancy that employed the commonly used bedside leukocyte-reduction filters failed to confirm a decrease in the rate of alloimmunization, except in a subgroup of patients with acute myelogenous leukemia. Another major multicenter trial confirmed the effectiveness of leukocyte-reduced blood components in the prevention of cytomegalovirus infection. The effect of allogeneic leukocytes in transfused blood on immune function in patients undergoing colorectal surgery continues to receive attention. Whereas one study failed to demonstrate an adverse effect of standard blood components on disease recurrence or survival, a second study demonstrated a marginally significant decrease in infectious complications in patients who received only leukocyte-reduced blood. Increasingly efficient leukocyte-reduction filters have been developed for cellular blood components, many of which are best suited for laboratory filtration of unstored blood. Laboratory studies indicate that prestorage leukocyte-reduction of cellular blood components does not impair erythrocyte or platelet function and will not increase the incidence of microbial contamination of blood. New methods that employ flow cytometry should enable improved quality control of blood components rendered leukocyte-reduced by the newer, more efficient filters. Finally, a cost-benefit analysis suggests that the appropriate use of leukocyte-reduction filters for acute leukemia patients may reduce the cost of health care to these patients.