In vitro evaluation of a high-efficiency leukocyte adherence filter

Abstract

In view of the currently available data, prevention of alloimmunization requires filters with higher efficiency to achieve a reduction in the number of leukocytes below 10 million per transfusion. Two versions (Pall PL-100 and PL-50) of the new generation leukocyte-depletion filters were studied. Single donor (SDPC)- and pooled multiple donor (MDPC) platelets were run in parallel. At a flow rate of 10 ml/min, the PL-100 filter was shown to effectively reduce the number of residual leukocytes to far below the critical immunogenic threshold of 10 million in all SDPC units and in 77% of MDPC units. Apheresis platelets appear not only to be better depleted than pooled multiple donor platelets, but also to have a better post-filtration platelet recovery (96% versus 84%). The efficiency of the smaller version of the filter (Pall-50) was higher than that of the Pall-100 filter for both single and pooled multiple donor platelet concentrates (PC). Leukocytes were absent in more than 92% of units in both types of concentrates. The maximal number of detected leukocytes was 2.2 million in a pool of 6 units. The outcome of filtration of 5-day-old pooled platelets was less favorable than filtration of 1- or 2-day-old pooled platelets, indicating that filtration soon after preparation is preferred to filtration after storage. Post-filtration platelet integrity, activation state, function, and morphology were all well preserved in both single and multiple PCs.

Gene Expression Analysis in Platelets from a Single Donor: Evaluation of a PCR-Based Amplification Technique

“…After one filtration, leukocytes were not detectable by flow cytometry analysis, and negative array results were obtained for CD45 and CD14 transcripts. These results support previously published data obtained on large-volume preparations of platelets (3,26 ). When we used a more sensitive quantitative RT-PCR approach, however, low concentrations of CD45 transcripts were detectable, indicating that the filtered PRP was not completely devoid of leukocytes.…”

Effect of Filtration on Subsequently Stored Platelet Concentrates

“…Moreover in the majority of these studies the platelets were only investigated directly after filtration and not dur ing subsequent storage [14][15][16][17][18]. In a few studies filtration was performed after storage for several days [15][16][17],…”

Leukoreduction of Platelet Concentrates Using a ‘Polishing’ Filter

“…This compares favorably with the ‘large’ housing filters, with platelet losses ranging from 5 to 20% [4, 5, 6, 7]. Interestingly, one of these filters also had a volume of 8 ml [4], as the ‘polishing’ filter in this study.…”

“…This compares favorably with the ‘large’ housing filters, with platelet losses ranging from 5 to 20% [4, 5, 6, 7]. Interestingly, one of these filters also had a volume of 8 ml [4], as the ‘polishing’ filter in this study. This filter, however, had a platelet loss of approximately 7%, indicating that the retaining surface and the characteristics of the polyester fibres are important, and not simply the dead volume of the filter.…”

“…have a sufficient leukoreducing efficiency. These filters generally have a large dead volume, resulting in a high platelet loss in tubing and housing ranging from 5 to 20% [3, 4, 5, 6, 7]. …”