Applications of ultraviolet light in the preparation of platelet concentrates

Passenger lymphocytes in platelet concentrates (PCs) may induce the formation of lymphocytotoxic antibodies (LCTAbs) and subsequent refractoriness to platelet transfusions. Ultraviolet (UV) irradiation can prevent lymphocytes' acting as stimulator or responder cells in mixed-lymphocyte reactions (MLRs) and could theoretically prevent LCTAb formation in vivo. A system has been devised for the delivery of UV irradiation to PCs; platelet storage characteristics and MLRs were evaluated in UV-irradiated PCs harvested from healthy donors with the Haemonetics V50 and PCS cell separators. MLR and response to phytohemagglutinin stimulation were abolished by a dose of 3000 joules per m2 at a mean wavelength of 310 nm. Platelet aggregatory responses to adenosine diphosphate (ADP), ristocetin, collagen and epinephrine, hypotonic shock response, and pH showed no important differences when control PCs and PCs irradiated as above were compared during 5 days of storage in Fenwal PL-1240 packs. Lactate production during storage was significantly higher in UV-treated PCs (p less than 0.001), but values did not exceed 20 mmol per L. UV transmission at 310 nm in standard blood product containers, including the Fenwal PL-146, PL-1240, and PL-732, was low (less than 30%), but it was acceptable in the Delmed Cryostorage and DuPont SteriCell packs (greater than 50%). UV irradiation may provide a simple and inexpensive means of producing nonimmunogenic PCs.     

Storage of single donor platelet concentrates: Paired comparison of storage as single or double concentrates

Modern cell separators allow the collection of two plateletpheresis concentrates (PCs) at one session. This study evaluates the quality of PCs stored as double concentrates in standard storage containers of two manufacturers. We collected 20 PCs that contained 4.5 × 10¹¹ platelets in 375 ml plasma (10 using the COBE Spectra and 10 using the Fresenius AS.TEC 204 with 500 ml bags) that were split into one unit of 3.0 × 10¹¹ platelets in 250 ml (3.0‐PC) and one of 1.5 × 10¹¹ platelets in 125 ml (1.5‐PC). Storage of one 3.0‐PC per bag of a two‐bag system corresponded to storage conditions for double PCs and storage of one 1.5‐PC per bag to storage conditions of single PCs. Cell counts, blood gas analysis, glucose and lactate levels, platelet aggregation, and activation and plasma levels of β‐ thromboglobulin (β‐TG) and complement factor 3a (C3a) were measured before storage and again on days 3 and 5. COBE 3.0‐PCs demonstrated less pH rise, lactate production, CD 62P expression and β‐TG plasma levels, and better aggregability after storage than COBE 1.5‐PCs. Fresenius 1.5‐PCs had similar platelet quality to COBE 3.0‐PCs. Fresenius 3.0‐PCs showed a fall of pH (day 5: 6.22 ± 0.56), the highest amount of anaerobic glycolysis compared to all other storage conditions investigated, high CD 62P‐ expression and β‐TG plasma levels, and impaired aggregability on days 3 and 5. The highest C3a levels were found in COBE 1.5‐PCs. 3.0 × 10¹¹ platelets in 250 ml plasma should be stored either in one bag of the COBE system or in two 500 ml bags of the Fresenius system. The COBE two‐bag system allows the storage of two PCs without loss of platelet quality. Two PCs should not be stored in the Fresenius C4L 500 ml storage containers. J. Clin. Apheresis. 16:148‐154, 2000. © 2001 Wiley‐Liss, Inc.     

Volume-reduced platelet concentrates: optimization of production and storage conditions

BACKGROUND: Plasma can be removed from platelet (PLT) concentrates (PCs) when volume reduction for PLT transfusion is indicated. Volume‐reduced PCs are currently produced from pooled buffy coat (BC) PCs or apheresis PCs by pretransfusion volume reduction, followed by transfer to a syringe for immediate transfusion. We evaluated the maximal storage time of the volume‐reduced PCs in gas‐permeable containers. STUDY DESIGN AND METHODS: Volume‐reduced PCs were produced from BC‐derived and apheresis PCs by hard‐spin centrifugation. Supernatant was removed and the PLTs were resuspended in 20 mL of retained original PC and had PLT concentrations ranging from 10.8 × 10⁹ to 13.8 × 10⁹ PLTs/mL. Volume‐reduced PCs were stored either in syringes or in containers made from diethylhexyl phthalate (DEHP)‐polyvinylchloride (PVC) or butyryl trihexyl citrate (BTHC)‐PVC plastic. Units were sampled at t = 0, 1, 3, and 6 hours for in vitro measurements. RESULTS: When prepared from 2‐day‐old PCs (n = 4), volume‐reduced PCs from BCs in a syringe had a pH_37°C of 5.76 ± 0.04 at t = 6 hours after volume reduction. In the DEHP‐PVC container, pH was 5.85 ± 0.15 (not significant), and in the BTHC‐PVC, 6.34 ± 0.16 (p < 0.001), at t = 6 hours. When made from 7‐day‐old PCs, pH was lower for all storage conditions: 5.68 ± 0.06 in the syringe, 5.70 ± 0.09 in the DEHP‐PVC container (not significant), and 6.07 ± 0.24 in the BTHC‐PVC container (p < 0.01) at t = 6 hours. Volume‐reduced 2‐day‐old apheresis PCs had a pH of 6.47 ± 0.20 at t = 6 hours. CONCLUSIONS: Adult‐dose PCs derived from BC or apheresis can be volume‐reduced to approximately 20 mL in a closed gas‐permeable system. Volume‐reduced PCs in BTHC‐PVC containers retain a mean pH of more than 6.0 up to 6 hours after production. Syringes allow only 3 hours of storage.     

Use of prostaglandin E1 during preparation of platelet concentrates

Summary. A paired study in 10 autologous volunteer donors was undertaken to investigate the efficacy of adding prostaglandin E₁ (PGE₁) in vitro during routine platelet concentrate (PC) production. After 5 days storage, PCs prepared with PGE₁ were compared with control PCs. In vivo platelet recovery, survival and biodistribution were determined following autologous infusion of indium-111 labelled platelets into volunteers, together with the in vitro evaluation of platelet function and biochemistry. PGE₁ facilitated easier and faster platelet resuspension following centrifugation. After storage there were few significant in vitro differences between PCs prepared with PGE₁ and control PCs. The artifactual leucocyte concentration was significantly lower in the presence of PGE₁, suggesting less platelet aggregates had been formed during storage and β-thromboglobulin release was significantly reduced by PGE₁, 14.0±6.0 μg per 10⁹platelets compared with 22.3±9.8μg per 10⁹platelets in control PCs, (P < 0.01), indicating PGE₁ reduced both platelet aggregation and activation probably at the initial preparation stage, known to produce the greatest trauma. Initial in vivo platelet recovery for PCs prepared with PGE₁ was similar to that of control PCs, 41.1 ± 12.5% vs. 44.4±80%, respectively, and there were no differences in organ distribution at 24h. However, in vivo multiple hit survival was reduced in the presence of PGE₁, 5.8 ± 1.6 days compared with 6.9 ± 1.4 days in control PCs (P < 0.05). Despite the ability of PGE₁ to facilitate platelet resuspension and inhibit platelet aggregation and activation during preparation of the PCs, the reduced in vivo survival time may preclude the use of PGE₁ during routine PC preparation.     

Extended storage of single-donor platelet concentrate collected by a blood cell separator

Use of a sealless blood pathway in a blood cell separator (CS-3000, Fenwal) permits collection of platelets in a "closed system" when saline and anticoagulant solutions are integrally attached; this in turn allows storage of instrument-collected platelet concentrates (PCs) beyond 24 hours. To evaluate extended storage of high yield PCs, cells collected with the instrument were stored (200 ml plasma) for 8 days (flatbed agitation) in either 3-liter polyvinylchloride (PL 146) containers (n = 6), polyolefin bags (PL 732) (n = 8), or two 1-liter polyolefin (double PL 732) containers (n = 8). A mean of 4.45, 4.09, and 3.94 X 10(11) platelets were stored in PL 146, single PL 732, and double PL 732, respectively; total white cells per container averaged 0.3, 0.2, and 0.2 X 10(9) for the three container systems. By day 1, platelet pO2 dropped to 14 and 16 torr in PL 146 and PL 732 PCs (pCO2, 127, and 82 torr). In contrast, double PL 732 maintained high pO2 (approximately equal to 80 torr) and low pCO2 (approximately equal to 30 torr) through day eight. Glucose declined at faster rates in PL 146 and single PL 732 containers, while lactate increased more rapidly (338 and 197 mg/dl of lactate on day four vs. 116 mg/dl for double PL 732 units). Morphology scores dropped from 400 to 98 (PL 146) and 216 (PL 732) at day four (pH values of 6.3 and 7.0), while a score of 330 was seen in double PL 732 PCs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison between a new PVC platelet storage container (UPX80) and a polyolefin container

During storage of platelet concentrates (PCs), the quality of the platelets deteriorates gradually, partially dependent on gas exchange. UPX80 (JMS, Japan) 1-L platelet storage PVC containers with increased gas transport capacity were compared with 1- and 1. 5-L polyolefin (PO) containers (NPBI, the Netherlands) with filtered PCs stored either in GAC (gluconate-acetate-citrate, < 10% plasma) or in plasma, for 8 days. In total 32 PCs were made (260-330 x 109 platelets per concentrate), equally divided over different bags and storage media. During storage, gas exchange, metabolic, physical and activation parameters were measured. No consistent differences for all parameters were observed between UPX80 and PO containers (1-L or 1.5-L). Blood gas parameters indicated better gas exchange for UPX80 containers compared with PO containers. Good morphology was observed in UPX80 and metabolic functions were not significantly different compared with PO containers. During prolonged storage (after day 6), some significant differences in CD62P and CD63 expression were found, indicating a higher degree of platelet activation in UPX80 containers, especially in GAC. UPX80 PC containers are suitable for storage of PCs. Although in UPX80 better gas exchange is demonstrated, as compared with PO containers, this does not improve the platelet quality during storage for 6 days, indicating that gas exchange above the level of PO containers has no effect on the switch to aerobic metabolism in platelets.     

Platelet capacity of various platelet pooling systems for buffy coat-derived platelet concentrates

BACKGROUND: Platelet (PLT) storage lesions might depend on the total PLT count in the storage container and also on the PLT pooling system, especially the storage container, that is used for preparation of PLT concentrates (PCs). In this study, the PLT capacity of four commercially available PLT pooling systems was studied. MATERIALS AND METHODS: Four PCs were prepared in pooling systems of Baxter, Fresenius, Terumo, or Pall. The PCs were pooled and divided with various total PLT counts over the four storage containers (<225 × 10⁹, 225 × 10⁹‐324 × 10⁹, 325 × 10⁹‐424 × 10⁹, and >424 × 10⁹ PLTs). Volumes were kept equal by adding plasma to PCs with less than 425 × 10⁹ PLTs until a same volume as for PCs with more than 424 × 10⁹ PLTs was reached. PCs were stored at room temperature and tested for various in vitro variables on Days 1, 3, 5, 7, and 9. Paired experiments were repeated for each system five times. RESULTS: In vitro variables remained good for 9 days, that is, swirling score of 2 or more, pH value of 6.8 or more, glucose level of 10 mmol per L or more, lactate level of less than 25 mmol per L, and CD62p expression of less than 50 percent, for PCs in Baxter systems with more than 225 × 10⁹ PLTs, for PCs in Fresenius and Terumo systems with 225 × 10⁹ to 424 × 10⁹ PLTs, and for PCs in Pall systems with fewer than 425 × 10⁹ PLTs. CONCLUSION: PLT capacity depended on the PLT pooling systems used. All systems provide acceptable storage conditions. The Baxter system was the only system with capacity for more than 424 × 10⁹ PLTs per PC.     

Evaluation of platelets collected by a new portable apheresis device

We studied the efficiency of platelet collection by the Mobile Collection System (MCS) using two types of experimental protocols and evaluated the effect of storage at 22°C on the platelet concentrates (PC). MCS is a new blood cell separator that combines discontinuous flow features with a new computerized operating system and can be used to harvest either full units of apheresis PC (SDP _protocol) or half units of PC together with one to two units of plasma (PLP _protocol). On the average, 1.98 × 10¹¹ ± 0.46 × 10¹¹ (mean ± SD) platelets were obtained by the PLP protocol and 3.01 × 10¹¹ ± 0.70 × 10¹¹ and 4.2 × 10¹¹ ± 1.12 × 10¹¹ by the early and later versions of the SDP protocols, respectively. The mean number of WBC per PC ranged from 3.3 to 4.7 × 10⁸. During the storage period pH stayed above 7.0. On the average, the production of one molecule of lactate corresponded to the consumption of 0.538 molecules of glucose, indicating that less than 8% of glucose was consumed by the oxidative pathway. There were only small increases in LDH and B thromboglobulin concentrations. Furthermore, the ability of platelets to recover from osmotic shock and to aggregate following exposure to dual agonists declined only slightly during storage, indicating that both viability and function of platelets collected by the MCS were preserved during storage. © 1993 Wiley-Liss, Inc.     

Storage of pooled platelet concentrates. In vitro and in vivo analysis

The use of sterile connecting devices will permit up to 5-day storage of pooled platelet concentrates (PCs). However, there are no data evaluating long-term storage of PCs pooled from multiple donors. Four units of ABO-compatible or -incompatible PCs were pooled and stored in single 300-ml PL-732 storage bags for up to 5 days. Results of in vitro assays showed acceptable storage values regardless of the ABO types in the pool. Pool pH on Day 5 was 6.83 +/- 0.3 (mean +/- 1 SD). The in vitro storage characteristics were comparable to those of unpooled age-matched platelets reported previously from our laboratory. For in vivo studies, 4-unit pools of ABO-compatible random-donor PCs stored for up to 96 hours in 1000-ml PL-732 bags were transfused into patients who were thrombocytopenic due to bone marrow failure, and the correct count increments (CCI) were determined. In vivo results showed a mean 1-hour CCI of 11,368 +/- 5824 for the pooled stored platelets and 7819 +/- 5189 for unpooled controls (p greater than 0.05). To evaluate the possibility that passenger lymphocytes in the concentrates would generate mixed lymphocyte reactions (MLR) in the pooling bag during storage, lymphocytes were studied over 5 days of storage by the use of monoclonal antibodies against activated T-cell markers and by 3H thymidine uptake. Results failed to show evidence of either the generation of activated T-cell markers or the uptake of 3H thymidine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Quality of irradiated and non-irradiated plateletpheresis concentrates stored in platelet additive solution

Introduction

Platelet additive solutions (PAS) allow to maintain platelet storage properties in platelet concentrates (PCs). The aim of the present study was to evaluate the in-vitro quality of irradiated and non-irradiated PCs, suspended in PAS, over a storage period of 6 days.

Preparation and storage characteristics of white cell-reduced high-concentration platelet concentrates collected by anapheresis system for transfusions in utero

BACKGROUND: Important concerns with regard to in utero platelet transfusions are avoidance of volume overload and the immunomodulatory effects of residual white cells (WBCs). This study evaluated a modification of a leukocyte‐reduction system (LRS, Spectra, COBE BCT) for apheresis, which collects high‐concentration WBC‐reduced platelets (HCPs) for in utero transfusion. STUDY DESIGN AND METHODS: The LRS procedure was modified by running the platelet collection pump at specified low flow rates (Q_col) for the first part of the procedure, collecting HCPs by gently purging them from the LRS chamber into a designated collection bag and then restoring the original LRS procedure settings to collect a second standard apheresis platelet concentrate (PC). Two centers carried out 32 procedures. Platelet yield, residual WBCs, and in vitro platelet function studies were evaluated. RESULTS: Platelet concentrations in 60 mL of HCPs were predictable according to Q_col (r² = 0.735). HCP yields varied from 0.9 to 3.2 × 10¹¹, depending on the desired final platelet concentrations in 60 mL, with an overall average of 1.92 × 10¹¹ (n = 32). Apheresis PCs had a mean platelet yield of 2.9 × 10¹¹ (1.3‐4.4 × 10¹¹, n = 20) and 3.9 × 10¹¹ (2.2‐5.8 × 10¹¹, n = 12) at concentrations of 1.3 × 10¹² per L for single‐needle and dual‐ needle procedures, respectively. Median WBC counts were 5.6 × 10³ for HCPs and 2.0 × 10⁴ for apheresis PCs, with >99 percent expected to be less than 1 × 10⁶. HCP in vitro characteristics were equivalent to those of apheresis PCs at 24 hours after collection. In vitro performance declined over storage as a function of HCP yield. HCP pH at 22^oC was maintained at a level of >6.2 for more than 3 days for yields >1.6 × 10¹¹, less than 2 days for yields 1.6 to 2.2 × 10¹¹, and less than 24 hours for yields >2.2 × 10¹¹. HCPs showed good in vitro characteristics and could be stored for 1 to 3 days, depending on the total number of platelets collected. CONCLUSION: A standard apheresis PC and an HCP requiring no secondary processing can be collected with the Spectra LRS. The platelet concentration may be determined by clinical need. HCPs meet the requirements for components that are transfused in utero.     

Phenolsulphotransferase in human tissue: Radiochemical enzymatic assay and biochemical properties

Phenolsulphotransferase (EC 2.8.2.1) (PST) is an important catecholamine and drug metabolizing enzyme. Optimal conditions have been determined for the accurate measurement of PST activity in the human platelet, human renal cortex, and human jejunum with a radiochemical microassay. 3-Methoxy-4-hydroxyphenylglycol (MHPG) and ³⁵S?3'-phosphoadenosine-5'-phosphosulfate (³⁵S-PAPS) were the substrates for the reaction. The apparent Michaelis-Menten (K_m) values for MHPG with platelet, renal cortex, and jejunum were 1.09, 0.46 and 1.16 mmol/l, respectively. Apparent K_m values for PAPS in the same tissues were 0.14, 0.13 and 0.21 μmol/l. The pH optimum of the reaction in all three tissues was approximately 6.2-6.8 with three different buffer systems. The coefficients of variation for the assay of platelet, renal cortex, and jejunal activities were 6.2%, 3.4% and 4.4%, respectively. Mean platelet PST activity in blood samples from 75 randomly selected adult subjects was 5.0 ± 1.72 nmol of MHPG sulfate formed per hour per mg of platelet protein (8.3 × 10^?5 ± 2.9 × 10^?5μmol · min^?1 · mg^?1, mean ± S.D.). There was a 5-fold intersubject variation in platelet PST activity within two standard deviations of the mean value. Experiments in which partially purified human erythrocyte PST was added to platelet, kidney and gut homogenates under these assay conditions provided evidence that endogenous PST inhibitors did not affect the observed enzyme activity.     

Multiple pH measurement during storage may detect bacterially contaminated platelet concentrates

BACKGROUND: Bacterial contamination or platelet (PLT) metabolism can change the pH of stored PLT concentrates (PCs). Measurement of pH for quality control is currently done on a limited basis. An easy noninvasive method was developed to obtain sequential pH measurements over time, without risking contamination and/or consuming PCs. STUDY DESIGN AND METHODS: The objective was to measure pH profiles of bacterially contaminated PCs over 7 days of storage. Small‐volume PC storage bags with incorporated pH sensor were prepared and in vitro variables were tested using aliquots of PCs. The pH sensors were used to delineate trends associated with the deterioration of these PCs upon inoculation with 19 different bacterial strains and one yeast. RESULTS: Monitoring the pH trends in real time in a noninvasive fashion, most bacterial strains were detected within 24 to 72 hours after spiking into the bag. At the time of detection, bacterial concentrations had reached levels between 1 × 10³ and 1 × 10⁸ colony‐forming units/mL. Several strains had pH rebound after initial drop. Multiple noninvasive pH reads allowed bacterial detection whereas single pH reads could give false‐negative results. CONCLUSIONS: The noninvasive pH sensor facilitated the detection of most strains of bacterial contaminants within 3 days with no potential for sampling error.     

Platelet concentrates and ultraviolet light

Platelet concentrates (PCs) may be irradiated with ultraviolet light (UVL) to abolish mixed lymphocyte reactions (MLR) whilst retaining adequate function and this might therefore prevent recipient alloimmunization (AI). However, conventional platelet storage containers are relatively impermeable to UVL. We have undertaken studies of in vitro platelet storage using different plastic containers and also measured in vivo platelet recovery and survival after storage in DuPont Stericell bags which were found to be both UV-permeable and biocompatible. PCs irradiated with 3000 Joules/m² (J/m²) of UVL and then stored for 5 days appear suitable for transfusion and may prove to be non-immunogenic. Further in vivo studies of haemostatic efficacy and recipient alloimmunization are now warranted.     

Quality of platelet concentrates irradiated with UVB light: effect of UV dose and dose rate on glycocalicin release and correlation with other markers of the platelet storage lesion

Summary. The amount of membrane-associated glycoprotein Ib in platelet concentrates (PCs) irradiated with a high dose of UVB light has been shown to be significantly reduced after 48 h storage. We recently corroborated this finding when we noted an increase in the supernatant levels of glycocalicin (GC, a major segment of glycoprotein Ib) in UVB-treated PCs during storage. The aim of the present study was to determine whether GC release was related to both the UV dose and the rate of dose delivery. Plateletpheresis concentrates obtained from five donors were pooled and split into five equal parts. Four of these were treated with 7500 and 15000 mJ/cm² UVB using two prototype UV sources with differing rates of dose delivery; namely, Baxter (BAT) and British Aerospace (BAC) cabinets, with the latter having the slower rate of delivery. On days 1 and 5 of storage, GC levels in the supernatants of PCs were determined by ELISA. Moreover, the following parameters were also assessed: platelet and WBC count; hypotonic shock response (HSR) and platelet aggregation response to ADP, ADP +collagen, ADP + arachidonic acid and ristocetin; pH; supernatant levels of lactate, glucose, von Willebrand factor (vWf) and β-thrornboglobulin (βTG). The results revealed an association of GC release with UVB dose using both UV sources, although this was more apparent in the BAC system, in which glycocalicin release at day 5 of storage was as follows (μg/ml, mean ± SD): 4·8±0·3 and 9·5±3·6 at 7500 and 15000 mJ/cm² respectively. Moreover, at 15000 mJ/cm², PCs treated in the BAC system exhibited significantly higher levels of GC than those treated in the BAT system: 9·5±3·6 and 4·8± 3·6 respectively at day 5 of storage (P= 0·05). This differential GC increase in the BAC was coupled with a decrease in HSR and a significant increase in lactate and βTG levels compared with the BAT system. In contrast to the GC results, vWf supernatant levels in PCs treated with UVB were decreased relative to non-treated PCs of the same origin. Moreover, GC release correlated significantly with various standard tests of platelet function indicating its importance as a quality indicator for the investigation of the platelet storage lesion. Our results show that UVB not only increases GC release in a dose/rate-dependent manner but that it may also affect the quality of irradiated PCs and their shelf life.     

Comparison of the in vitro storage properties of Amicus apheresis platelets collected using single- and double-needle procedures from the same donors

BACKGROUND: Amicus apheresis platelets (PLTs) can be collected using either a single‐ (SN) or a double‐needle (DN) procedure. To investigate whether the method of PLT collection using the same instrument influences PLT quality, the in vitro storage properties of Amicus PLTs were evaluated in the same donors collected by SN and DN procedures. STUDY DESIGN AND METHODS: Single apheresis PLT collections with concurrent plasma were performed on donors using the Amicus with a target yield of 4 × 10¹¹. A PLT unit was collected from a donor assigned to either a SN or a DN procedure; a subsequent donation from the same individual was collected by the other procedure (n = 10). Units were stored at 20 to 24°C with continuous agitation, assayed for 19 PLT storage variables, and analyzed by paired t test, with differences between values obtained with SN and DN collections considered significant with p values of less than 0.001. RESULTS: PLT units collected by SN procedure had contents and concentrations similar to those collected by DN procedures (4.1 × 10¹¹ ± 0.3 × 10¹¹ vs. 4.0 × 10¹¹ ± 0.3 × 10¹¹ and 1396 × 10⁹ ± 131 × 10⁹ vs. 1367 × 10⁹ ± 110 × 10⁹ PLTs/L). On Day 7, SN and DN PLTs had comparable pH values (7.07 ± 0.09 vs. 6.99 ± 0.17), morphology (52.4 ± 18.7% vs. 56.0 ± 13.3% discoid), aggregation (87.1 ± 11.5% vs. 91.3 ± 5.4%), and activation (45.8 ± 11.9% vs. 48.2 ± 8.7% CD62P), as well as all other variables (p > 0.05; Day 7 CO₂, p = 0.0304). CONCLUSION: The in vitro storage properties of apheresis PLTs collected from the same donors using a SN and DN procedure with the Amicus instrument were maintained through 7 days of storage and yielded comparable results.     

Leukotrap,a device for white cell poor platelets quality control studies In vitro and In vivo

Most febrile transfusion reactions are due to leucoagglutinins. Cutter's Leukotrap platelet pooling bag has a distal conic pouch for depleting the platelets of white blood cells by centrifugation. We tested 33 Leukotraps each containing six platelet units in vitro and 32 in vivo. The mean in vitro platelet count was 3.7 ± 0.5 × 10¹¹ platelets before, and 3.0 ± 0.5 × 10¹¹ after spinning, representing a platelet recovery of 80.2 ± 9.6% Mean white blood cells were 3.8 ± 0.6 × 10⁸ before, and 0.6 ± 0.1 × 10⁸ after centrifugation, this constituting a white cell removal of 83.5 ± 7.7%. pH ranged from 7.37 for 24-h platelets to 7.19 for 96-h platelets. 24-h after platelet pooling, all Leukotraps were sterile. Platelet aggregation with physiologic agents showed little change compared to individual platelet units. Glucose ranged between 418 and 336 mg/dL, pCO₂ between 27.8 and 19.1 mmHg, but pO₂ dropped drastically from 74.8 mmHg to 11.6 mmHg. Hypotonic osmotic recovery was satisfactory. In vivo studies were carried out with pooled, leucocyte-poor platelets which were transfused to six bone marrow transplant patients with no splenomegaly or septicemia at the outset. These patients had all demonstrated febrile transfusion reactions to standard donor units. The mean platelet increment was 16.8 × 10⁹/L. A single febrile transfusion reaction witnessed in one patient, was accompanied by an adequate platelet response. Hence Leukotrap is a useful clinical tool for reducing febrile transfusion reactions related to white blood cells.     

Growth of gram-positive and gram-negative bacteria in platelet concentrates

In 1986 the allowable platelet storage time was reduced from 7 to 5 days because of a recent increase in septic deaths associated with platelet transfusion. In this study, the growth curves of two gram-positive and two gram-negative organisms in platelets stored for 7 days in CLX and PL-732 bags were evaluated. Platelets in CLX bags were inoculated with 10(1), 10(2), and 10(3) organisms and 10(2) organisms were introduced into PL-732 bags. Test organisms were inoculated into trypticase soy broth as a control. All four bacteria grew rapidly in trypticase soy broth, reaching 10(9) organisms per mL within 48 hours. In both CLX and PL-732 bags, the growth pattern of gram-positive organisms was generally logarithmic during the first few days of storage. A concentration of 10(8) organisms per mL was present by Day 3 or 4, after which further proliferation was inhibited by the high density of bacteria in the platelets. In PL-732 bags, the proliferation of gram-negative organisms followed a pattern similar to that of the gram-positive bacteria. However, gram-negative organisms grew less well in CLX bags.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of platelets prepared by apheresis and stored for 5 days. In vitro and in vivo studies

To evaluate the effect of storage on apheresis platelets collected with a closed-system blood cell separator, an in vitro investigation was performed, with measurements of pH, lactate, ATP, the ratio of ATP to the total adenine nucleotide content, and adenylate kinase. Unmodified apheresis platelets and apheresis platelets with plasma added were compared with conventional platelets stored in PL-1240 or PL-732 plastic containers. During 6 days of storage, there were similar changes in all variables with one exception: the extracellular activity of adenylate kinase was lower in apheresis platelets with plasma than in the other three groups (p less than 0.01). In vivo studies were carried out with 111Indium-labeled autologous platelets in eight volunteers. Apheresis platelets with 100 mL of plasma added were stored in two 1000-mL containers (PL-732) at 22 degrees C during agitation. Platelets from one of the containers were labeled with 111Indium and transfused into the volunteer within 24 hours. Platelets from the other container were labeled after 5 days of storage and transfused into the same donor. There were no significant differences between apheresis platelets stored for 1 day and those stored for 5 days: the mean percentage of recovery was 58.4 and 57.6 percent, t1/2 was 69 and 67 hours, and the survival time was 5.5 and 5.6 days, respectively.