Depletion of white cells from platelet concentrates with a new adsorption filter

Abstract

Removal of white cells (WBCs) from platelets may reduce alloimmunization to WBC antigens, prevent febrile reactions, and improve platelet increments in multiply transfused patients receiving HLA-matched platelets. A new surface-modified fibrous polyester filter was evaluated; it requires no special processing of pooled platelet concentrates and can be used at the patient's bedside. The studies were designed to measure WBC removal, platelet function, in vitro platelet recovery, and in vivo platelet survival. WBC mean removal was 99.8 percent +/- 0.56 (n = 37) when a pool similar in volume to 6 platelet concentrates was tested. The mean number of residual WBCs after filtration was 5.6 x 10(5). In vitro mean platelet recovery was 86.9 percent for a pool size of 6 units (n = 37). Clot retraction and platelet aggregation were unaffected by filtration. Survival studies of 111Indium-labeled platelets done with filtered autologous platelets showed no reduction in the normally expected survival. These studies indicated that the filter efficiently removes WBCs without substantially decreasing platelet number, survival, or function. This device offers the potential of considerably improving platelet transfusion therapy.

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

“…In addition, another important structural component of the platelet membrane, glycoprotein IlbIlla, was not modified by filtration. This further supports the conclusions of previous studies indicating that filtered platelets retain hemostatic effectiveness [9,21] and normal survival [15,17], The wide range of pre-and postfiltration values shown by GMP 140 could suggest that a proportion of our platelets were already activated before filtration, which confirms other data indicating that a slight level of activation may exist in some PC soon after preparation [22]. However, GMP 140 expression before filtration was lower than that found in platelets stored in polyolefin for 5 days [Bertolini et al, unpubl.…”

“…The results of our study indicate that leukocyte removal and platelet recovery are satisfactory with all three filters examined, although statistically significant variations in performance were found. Differences in platelet recovery and leukocyte con tamination among this study, our previous investigation [9] and other reports [15][16][17][18] are probably due to technical factors including the number of PC in the filtered pool, the method of residual leukocyte count, and the rinsing maneu ver which was performed by some investigators with vari-In summary, leukocyte removal of Sepacell PL-10A was higher than that of Pall PL100 and Imugard IG 500; this was associated to a significantly higher platelet loss than that with Imugard. Filtration through the three filters examined did not determine significant modifications of platelet membrane glycoprotein Ilb-IIIa and of other constituents related to platelet activation, in vivo recovery and survival.…”

“…This work is an extension to other studies which indicate that other parameters of platelet quality, i.e. pH [15,16], mor phology [16,17] and platelet function [15][16][17][18], are not signif icantly modified after platelet filtration. The results of our study indicate that leukocyte removal and platelet recovery are satisfactory with all three filters examined, although statistically significant variations in performance were found.…”

Platelet Concentrates Stored in Synthetic Medium after Filtration

“…Recently, a sterile connection device has become available, and storage of pooled and/or fil tered platelet concentrates appears to be practicable. Al though a number of investigators reported in vitro charac teristics and in vivo effectiveness of filtered PC evaluated soon after filtration [2][3][4][5], studies on the feasibility of PC storage after filtration are scanty. Instead of using the traditional method of PC preparation from platelet-rich Materials and Methods bound fibrinogen, a kind gift of Dr. Budzynski (Philadelphia, Pa., USA).…”

Transfusion Results of Filtered and Subsequently Stored Random Platelet Suspensions Prepared from Buffy Coats

“…Filters to remove leukocytes from erythrocyte trans fusions have been available for more than 10 years, but only recently have filters become available that could re move white cells from platelet suspensions without con siderable platelet loss [9][10][11]. A point of concern is wheth er filtration causes damage to platelets, as during the fil tration procedure platelets are exposed to foreign surfaces which may cause platelet activation with release of in ternal constituents, compromising clinical efficacy of the transfused platelets.…”