Abstract. Using the filtration method described earlier, leukocytes were removed from units of fresh whole blood and erythrocyte suspensions (hematocrit 50%). After filtration, the units were stored for one or two weeks. Units of whole blood and erythrocyte concentrates were stored for periods up to three weeks, the leukocytes were then removed by filtration, and the units were stored for another week. During the storage period, the following parameters were measured: pH and concentrations of ATP + ADP, 2,3‐diphosphoglycerate, hemoglobin and potassium (Hb and K+ in the cell‐free supernatant). The parameters used in the present study indicate that removal of leukocytes by filtration did not cause significant alteration to stored whole blood and erythrocyte concentrates, compared to unfiltered blood stored for the same time.

Abstruct. Using the filtration method described earlier, leukocytes were removed from units of fresh whole blood and erythrocyte suspensions (hematocrit 50%). After filtration, the units were stored for one or two weeks.Units of whole blood and erythrocyte concentrates were stored for periods up to three weeks, the leukocytes were then removed by filtration, and the units were stored for another week.During the storage period, the following parameters were measured: pH and concentrations of ATP + ADP, 2,3-diphosphoglycerate, hemoglobin and potassium (Hb and K+ in the cell-free supernatant). The parameters used in the present study indicate that removal of leukocytes by filtration did not cause significant alteration to stored whole blood and erythrocyte concentrates, compared to unfiltered blood stored for the same time. D~PENHOR~//SPROKHOLT/PRINS(DPG), free hemoglobin, and potassium (Hb and K + in the cell-free supernatant). We measured ATP + ADP because of the close correlation between ATP level and erythrocyte viability [l, 51. DPG was measured as low levels are known to cause decreased oxygen release to the tissues [9]. Materials and MethodsCollection of blood andpreparation of red cell concentrates. Blood was collected in the evening prior to the experiments, as described earlier [2], and either cooled in the usual way or immediately after collection. Cooling in the usual way was effected as follows: bottles were put in a cold room (2°C) approximately 4 h after collection, PVC bags were put in a metal box containing ice cubes approximately 1 h after collection.Rapid cooling was obtained by putting bottles and PVC bags in melting ice immediately after collection, followed by storage in a cold room (2°C).When needed, erythrocyte concentrates were prepared by centrifugation (30 min at 1,350 g ) and aspiration of the plasma.In one experiment, a pool was made of several units of ACD erythrocyte concentrate with the same ABO blood group and Rh factor. Filtration.Filtration was performed using the filter system described earlier [2]. Part of each unit was not filtered but kept to serve as a noniiltered control sample.Storage. In one experiment, units of whole blood and erythrocyte concentrates were stored in the bottle in which they were taken for periods up to three weeks at 2°C prior to filtration.In two other experiments, the storage period was limited to one night. After filtration, the suspensions were put in screwcapped, sterile plastic tubes, one for each day of storage, and stored at 2°C; so were the nonfiltered control samples. Determination of p H , ATP + ADP, DPG, free hemoglobin and potassium.Each day during the experiment, a tube of each series was opened after thorough mixing.The pH was determined on the day of opening and samples for the other determinations were stored at -20°C. After approximately one week, the other parameters were measured simultaneously.The glycolytic intermediates: ATP + ADP, DPG, were determined in 900 and 27,000fold dilutions of blood samples by mechanized enzymatic methods [...

Hetero-immunization experiments in rabbits were performed to evaluate the quantity of leucocyte antigens present in red cell suspensions prepared by the filtration method of DIEPENHORST et al., in which no intact leucocytes could be detected. It was found that the quantity of leucocyte antigens is smallest in blood filtered immediately after taking. More leucocyte-antigenic material seems to be present in blood that is filtered after storage and in frozen-thawed red cell suspensions. Evidence was obtained that granulocyte-specific antigens are more strongly immunogenic in the rabbit than lymphocyte-specific antigens or antigens common to both cells.

Abstract. (1) Sterile filtration of whole blood or blood cell suspensions in saline through columns of tightly packed cotton wool results in removal of over 95% of the leukocytes. (2) From whole blood, thrombocytes are inefficiently removed by the filtration procedure; filtration of blood cell suspensions in saline results in a better removal. (3) A system is designed by which filtration of 500 ml portions can be performed in less than 1 h at room temperature. (4) Red cell recovery with this system is over 90%. (5) Neither pyrogen tests nor toxicity tests did reveal the elution of harmful substances from properly prepared columns.

1,820 units of leukocyte- and platelet-poor erythrocyte suspensions were prepared by filtration through cotton wool. On the average more than 98% of the leukocytes and 90-95% of the platelets could be removed. The red cell recovery was 96%. 97% of the units given to polytransfused patients did not cause febrile reactions. Serological follow-up of future transplantation recipients indicated that the immunization may be avoided by using erythrocyte suspensions of fresh, filtered blood.