Adsorption filtration of leukocyte-reduced single donor platelet units

The effect of adsorption filtration of leukocyte-reduced single donor platelet (SDP) units collected on a CS-3000+ with a TNX chamber was compared to filtration of SDP units prepared via an isoradial chamber. The leukocyte enumeration technique employed a Nageotte chamber and had a nominal lower detection limit of 0.05 leukocytes/microliter (if no cells were seen, the concentration was recorded as 0.01 microliter). Although the prefiltration leukocyte content of the TNX units was unexpectedly low (2.4 +/- 2.8 x 10(4) per unit), filtration reduced the leukocyte content further to no greater than 1.7 +/- 0.07 x 10(3) (p < 0.05). (The full extent of the leukocyte removal could not be assessed as no leukocytes were seen in counting any of the 20 filtered TNX units). The 20 isoradial (control) SDP units achieved similar leukocyte depletion, with a postfiltration leukocyte content of 2.7 +/- 2.5 x 10(3) (p > 0.05, compared to filtered TNX units). Thus while significant leukocyte reduction occurred with adsorption filtration of both control and leukocyte-depleted SDP units, comparison of the relative degree of reduction awaits application of more sensitive leukocyte counting techniques. This study documented, however, that additional leukocyte reduction can be obtained by applying adsorption filtration to SDP units with an already low leukocyte content.