Effects of 3-5 log10 pre-storage leucocyte depletion on red cell storage and metabolism

A new, in-line high-efficiency 3-5 log10 leucodepletion filter system (Leukotrap RC system) was used to investigate the effect of pre-storage white cell removal on the quality of AS-3 red cell concentrates stored for 42 d at 4 degrees C. Median residual white cell content was 4 x 10(5) when filtration was performed at 22 degrees C within 8 h of phlebotomy (n = 20) and 3.2 x 10(4) when filtration was performed at 4 degrees C 12-24 h after phlebotomy (n = 24). None exceeded 1 x 10(6) WBC per red cell product. Filtration was rapid (median 28 min), and red cell loss averaged (mean +/- 1 SD) 6.4 +/- 0.7%. In a paired study design, post-transfusion recoveries of 42 d stored red cells in the filtered units averaged 84 +/- 6% v 82 +/- 8% for unfiltered units (P < 0.05) and post-storage haemolysis. ATP, osmotic fragility, K+ and pH were significantly (P < 0.05) better in the filtered units. Reduced glycolytic activity was also observed in the filtered units, and there was a correlation between osmotic fragility, glucose consumption, and lactate produced in standard units that was not present in leucodepleted units. In conclusion, this study suggests that leucodepletion of AS-3 red cell concentrates prior to storage results in better maintenance of the integrity of the red cell membrane with reduced glycolytic activity. There was a modest improvement in post-infusion viability sufficient to offset the filtration-induced loss and to result in an equivalent red cell product.