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The purpose of the present overview was to determine the factors influencing the removal of infectious agents from red cell concentrates by filtration. In general, the efficacy of the filtration method depends on the physical as well as the functional properties of blood cells. These properties are highly influenced by the changes exerted on the blood cells during blood collection, processing and storage and the filtration method itself. In particular, the removal of infectious agents of red cell concentrates by filtration will be determined by the type of virus and therewith the binding towards leukocytes, the type of bacteria and holding period before filtration, the deformability of infected cells and the disintegration of cells in the filter.

For hygienic purposes, plastic overwraps can be used for storage of leucoreduced red cell concentrates (LR-RCC). However, the effect of the use of such overwrapping on in vitro parameters during 42 days of storage was unknown.In paired experiments, LR-RCCs in SAGM (saline, adenine, glucose, mannitol) were packed in two types of polyethylene overwrap or in a polypropylene overwrap; no overwrap served as reference (n = 12 paired experiments). Units were stored at 2-6 degrees C for 42 days and sampled at regular intervals for in vitro analysis.No significant effect was found for any of the overwraps investigated. All units contained2.7 micromol adenosine triphosphate per gram haemoglobin and had a haemolysis rate well below 0.8% on Day 42.The use of plastic overwraps does not affect red cell quality markers in vitro.

We showed earlier that metabolically suppressed platelets (MSP) prepared by incubation in glucose-free, antimycin A medium at 37 degrees C better sustained storage at 4 degrees C than untreated controls at 22 degrees C. However, the use of the mitochondrial inhibitor antimycin A is incompatible with platelet transfusion.The aim of this study was to investigate how energy-reduced (ER) platelets could be prepared in the absence of antimycin A.Platelets in gas-impermeable bags in glucose-free medium were kept at 22 degrees C for 4 h to reduce energy stores and thereafter stored at 4 degrees C (ER22-4). Controls were energy-reduced platelets without prior incubation at 22 degrees C (ER4), and MSPs in test tubes and untreated platelets in gas-permeable bags with glucose and stored at 22 degrees C (C22) and 4 degrees C (C4).After 48 h storage, ER22-4 were superior to C22 with respect to pH preservation (6 x 4 +/- 0 x 4 vs. 5 x 0 +/- 0 x 4, n= 4), platelet count (800 +/- 225 vs. 650 +/- 150 x 10(9)), thrombin receptor-activating peptide-induced aggregation (50 +/- 15 vs. 10 +/- 5%) and glycoprotein (GP)Ib alpha expression (60 +/- 15% vs. 28 +/- 15). GPIb alpha expression was higher in ER22-4 than in ER4, indicating that energy suppression preserved GPIb alpha during cold storage.Metabolic suppression without the use of antimycin A could be mimicked by storage of platelets in glucose-free medium in gas-impermeable bags. Energy suppression preserved GPIb alpha expression during storage at 4 degrees C.

Summary Propionibacterium acnes is implicated in most cases of bacterial contamination of platelet concentrates (PCs). To determine the source of contamination, amplified-fragment length polymorphism (AFLP) analysis was applied. This DNA fingerprinting technique was used to study the molecular relationship of 44 isolates derived from 22 PCs and 22 corresponding red blood cells concentrates (RBCs) from the same whole blood donations. The AFLP results together with sequencing analysis of the 1200 bp of the 16S ribosomal RNA gene revealed the existence of three main groups: two groups (groups 2 and 3) (55%) consisted of isolates that did not originate from skin flora and another group (group 1) (45%) comprised bacteria belonging to the skin flora. This latter group showed complete homology with reference strains of P. acnes. Therefore these isolates can be considered as P. acnes strains. In contrast, contaminants from groups 2 and 3 were shown to be molecularly unrelated to the P. acnes found on the skin surface. The AFLP is reproducible and gave invaluable information about the nature of Propionibacteria contaminating PCs. To gain more insights into the source of contamination, this technique could be exploited in further studies to determine the molecular relationship of different bacteria commonly found in blood products.

Bacterial screening and improvement of storage conditions of leukoreduced PLT concentrates (LR-PCs) allows extension of their storage period from 5 to 7 days.For in vitro studies, 40 LR-PCs made from five buffy coats and plasma were studied for 8 days. For in vivo studies, routinely produced LR-PCs stored for 2 to 7 days after blood collection were administered to clinically stable thrombocytopenic patients. CI1 h was calculated after 353 transfusions (67 patients), and CCI1 h, after 195 transfusions (55 patients), with pretransfusion PLT counts of not greater than 20 x 10(9) per mL.Storage experiments showed that the pH of LR-PCs remained greater than 6.8 for 8 days, provided that the PLT concentration was less than 1.3 x 10(9) per mL. Routinely produced LR-PCs had a volume of 282 +/- 15 mL (n = 10,193) and contained 329 x 10(9)+/- 40 x 10(9) PLTs (n = 3467). For 7-day-old LR-PCs, 76 of 78 (97%) of the transfusions resulted in a CI1 h of at least 10 and 37 of 39 (95%) in a CCI1 h of at least 7.5, which indicated levels for successfulness. Mean +/- SE values of CI1 h and CCI1 h of 7-day-old LR-PCs were 28.7 +/- 2.3 (n = 78) and 19.0 +/- 2.0 (n = 39), respectively. No significant differences were observed between 5- and 7-day-old LR-PCs transfused with respect to CI1 h and CCI1 h values.In vitro and in vivo studies showed that LR-PCs can be stored for up to 7 days with excellent clinical results, provided that they are routinely screened for bacterial contamination.

In anderen Beitragen dieses Bandes wird bereits auf die allgemeinen Qualitatsbedurfnisse fur die Lagerbarkeit von Thrombozytenkonzentraten eingegangen. Zu diesem The — menkreis sind noch folgende methodische Erganzungen anzufuhren

Leukocytes and platelets are known to adhere to a variety of materials [1]. Already in 1928, Fleming used cotton wool to remove leukocytes from small amounts of blood [2]. This was the basis for the preparation of leukocyte-poor red cell concentrates (RBC) for transfusion many years later [3,4]. In 1972 Diepenhorst et al. [3] described the first leukocyte depletion filter which was composed of a column filled with tightly packed cotton wool fibers, providing a network with equally distributed pores. The retention of both granulocytes and lymphocytes in this cotton-wool filter was independent of Ca2+ and Mg2+ and hematocrit and slightly temperature dependent.

High speed centrifugation allows separation of whole blood into cell free plasma, a buffy coat and leukocyte poor red cells. The buffy coat can be used for the preparation of platelet concentrates. High lactate production at 22°C requires storage of the buffy coat at 4°C. Survival in vivo of platelet concentrates prepared from buffy coats stored at 4°C for 48 h (BC-PC) was compared with the survival in vivo of platelet concentrates from platelet rich plasma stored at 22°C for 48 h (PRP-PC). Both methods were studied in the same healthy volunteers (n=8) using51Cr labeled autologous platelets. The mean ±SD recovery 15 min after reinfusion of the BC-PC was 30.5%±13.3% and for PRP-PC 41.4%±7.9% (p

A method is described to prepare platelet concentrates from the buffycoat of citrate-phosphate-dextrose (CPD) blood in a closed four-bag system and to store the platelets in autologous plasma under sterile conditions. After separation of the blood into plasma, buffycoat and leukocyte- and thrombocyte-poor red cell concentrate, saline-adenine-glucose-mannitol (SAGM) was added to the red cells. Next the platelets were concentrated in plasma by a second centrifugation and were transferred to the 600-ml bag that previously contained the SAGM. The platelets were stored for 72 h at 22 degrees C on a platform rotator at 1 cycle per second. The mean volume of the platelet concentrates (n = 12) was 61 ml, with an average platelet content of 72 X 10(9). The mean leukocyte contamination was only 17 X 10(6); erythrocytes were not detected. The aggregation of the platelets with 1 microM of ADP was normal. After 72 h of storage, the mean pH was 7.1 +/- 0.1. The PO2 always remained above 17 mm Hg. No loss of thrombocytes had occurred during storage. The platelets had retained their discoid shape. The aggregation response to ADP had disappeared, however. The in vivo viability of the platelets was determined in 8 healthy volunteers. Autologous platelets, stored for 72 h at 22 degrees C, were labeled with 51 Cr and reinfused [43 (+/- 9)% recovery at 15 min after reinfusion]. The mean survival time in vivo of the platelets was 6.8 (+/- 0.7) days.(ABSTRACT TRUNCATED AT 250 WORDS)