USE OF POLYESTER LEUKOCYTE ELIMINATION FILTERS IN BLOOD FILTERABILITYRESEARCH

We rested a new routine to eliminate leukocytes for blood rheology mea surements using commercial leukocyte absorbing filters (here PALL RC40 0). These filters were punched out and fitted in smaller chambers thro ugh which blood was filtered under controlled suction pressure (< 30 m m Hg). This technique resulted in a very effective leukocyte eliminati on to 0.0022% but also a platelet reduction to 0.2%. The process cause s a small but significant hemolysis with free hemoglobin, of the order of 0.06% of the filtered erythrocytes. A small fraction of the erythr ocytes were retained in the filter, versus plasma, to reduce the hemat ocrit on the order of 1.4%. The leukocyte filtration did not cause any detectable functional trauma to the erythrocytes, measured as micro-p ore filterability of normal and glutaraldehyde (GA) hardened erythrocy tes. However, when 10% of the erythrocytes were hardened with GA, whic h caused an increase in pore clogging slope (p < 0.05), the additional passage through the leukocyte elimination filter removed this measure d change in clogging. This observation suggests that the leukocyte eli mination filter may selectively remove, not only leukocytes and platel ets, but also hardened erythrocytes. Reticulocyte counting did not rev eal any selective removal of young erythrocytes. In general, we find t he presented method reproducible, efficient and easy for eliminating l eukocytes for blood rheology research although the risk of removing un deformable erythrocytes must be considered.