Comparison of Platelet Activation and Membrane Glycoprotein lb and IIb-IIIa Expression after Filtration through Three Different Leukocyte Removal Filters

Abstract

We evaluated three filters used for leukocyte removal from platelet concentrates: Imugard IG 500, Pall PL100 and Sepacell PL-10A. Filter performance, platelet activation and expression of membrane glycoproteins lb and Ilb-IIIa were evaluated. Imugard, Pall and Sepacell showed median postfiltration in vitro platelet recoveries of 88, 84 and 80%, and total residual leukocyte counts of 16.1, 7.5 and 0.6 x 10^6/pool of 8 platelet concentrates, respectively. Mean platelet volume was reduced after filtration with all filters. Postfiltration values of glycoproteins lb and Ilb-IIIa, and of activation markers GMP140 and gp 53 were not significantly different from prefiltration values. Filtration through Imugard, Pall and Sepacell did not induce significant platelet activation or modifications of platelet membrane glycoproteins lb and IIb-IIIa.

Platelet Concentrates Stored in Synthetic Medium after Filtration

“…In this study we did not observe any signif icant difference in filtered platelets mean size compared to controls. These data differ from the results of other studies performed in our and other laboratories [5,15] on platelets suspended in plasma. The reason for this differ ence may be related to the synthetic medium used for BCPC storage in the present study.…”

“…In this study we evaluated platelet in vitro viability, metabolism and activation during 15-day storage of filtered and control BCPC. In previous experi ments [15], we demonstrated that filtration procedures do not induce significant platelet activation or modifications reports demonstrating an increase of platelet-bound fibri nogen during storage; this two-step process needs a con version of membrane Ilb-IIIa complexes into functional fibrinogen receptors before ligand binding to the exposed receptors. The 9F9 antibody used in this study is known to bind to platelet-bound fibrinogen and not to fibrinogen in solution, and was previously used [24] to evaluate the extent of platelet activation.…”

“…Internal standards of fluorescence were run in each experiment. Previous studies [15] demonstrated that washing procedures do not significantly increase the expression of activation markers on platelets.…”

“…On day 1, 5 and 15 of storage we measured the following in vitro variables, as previously described: pH at 22 °C, pCO ,, pO 2 [6]; micro scopic leukocyte count [15]; glucose and lactate, bicarbonate concen tration, oxygen consumption rate [16] ; osmotic reversal reaction [17]. Since previous studies [18] demonstrated that an increase of platelet size dispersion during storage is associated with a decrease of in vivo survival, a Sysmex TOA NE-8000 automatic counter (Sysmex, Kobe, Japan) was used to evaluate platelet count, platelet arithmetic distri bution width (PDW), precent of platelets larger than 12 fl and mean platelet volume.…”

“…Platelet membrane glycoprotein lb and activation markers were evaluated as previously described [15] using the following monoclonal antibodies: (1) CD42b (clone SZ2, Immunotech, Marseille, France), reacting with glycoprotein lb; (2) CD62 (clone CLB-thromb/6, Im munotech), reacting with alpha granule activation marker GMP-140; (3) CD63 (clone gran 12, Immunotech), reacting with activation marker gp 53, alysosome-like protein; (4) 9F9, reacting with platelet- [12,21] and in vivo [22] data on filtered PC evaluated after storage. Similarly to Holme et al [21], we found no significant differences on day 5 of storage when filtered and control BCPC were compared.…”