Platelet storage lesion in interim platelet unit concentrates: A comparison with buffy-coat and apheresis concentrates

Platelet storage lesion is characterized by morphological changes and impaired platelet function. The collection method and storage medium may influence the magnitude of the storage lesion. The aim of this study was to compare the newly introduced interim platelet unit (IPU) platelet concentrates (PCs) (additive solution SSP+, 40% residual plasma content) with the more established buffy-coat PCs (SSP, 20% residual plasma content) and apheresis PCs (autologous plasma) in terms of platelet storage lesions. Thirty PCs (n = 10 for each type) were assessed by measuring metabolic parameters (lactate, glucose, and pH), platelet activation markers, and in vitro platelet aggregability on days 1, 4, and 7 after donation. The expression of platelet activation markers CD62p (P-selectin), CD63 (LAMP-3), and phosphatidylserine was measured using flow cytometry and in vitro aggregability was measured with multiple electrode aggregometry. Higher platelet activation and lower in vitro aggregability was observed in IPU than in buffy-coat PCs on day 1 after donation. In contrast, metabolic parameters, expression of platelet activation markers, and in vitro aggregability were better maintained in IPU than in buffy-coat PCs at the end of the storage period. Compared to apheresis PCs, IPU PCs had higher expression of activation markers and lower in vitro aggregability throughout storage. In conclusion, the results indicate that there are significant differences in platelet storage lesions between IPU, buffy-coat, and apheresis PCs. The quality of IPU PCs appears to be at least comparable to buffy-coat preparations. Further studies are required to distinguish the effect of the preparation methods from storage conditions.     

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.     

Transfusion of platelet concentrates from pooled buffy-coats: comparison of bedside vs. prestorage leukofiltration

Prestorage leucocyte filtration of platelet concentrates (PC) has been considered to be superior to bedside filtration with regard to the incidence of nonhaemolytic transfusion reactions (NHTR) or HLA-alloimmunization. It is currently a matter of debate whether prestorage leucocyte filtration has an impact on the storability of platelets and on the transfusion results of PC. In a clinical retrospective study we investigated the transfusion results of PC from pooled buffy-coats (PC-BC) in haematological patients without known refractoriness to platelets, and compared bedside filtration (n = 228/36 patients) vs. prestorage filtration (n = 271/25 patients). Leukocyte and platelet content of the PC, duration of storage, platelet count of the patient before transfusion and 20 h after transfusion were determined and platelet increment and corrected count increment (CCI) 20 h after transfusion were calculated. The mean leucocyte content of the bedside filtered PC was 66 +/- 50 x 106 and < 0.1 x 106 for the prestorage filtered PC (P < 0.001). Mean platelet content of the PC (2.6 x 1011 vs. 2.7 x 1011) and the duration of PC storage (2.7 vs. 2.6 days) were almost identical in both groups. The platelet increment after 20 h (14.6 x 109 L-1 vs. 14.9 x 109 L-1) was equal for both groups, but CCI values were significantly higher for the bedside filtered PC (14.1 +/- 9.5 vs. 11.4 +/- 6.8) (P = 0.008). Correlation with the storage time revealed that CCI levels were higher for bedside filtered PC after short-term storage (< 36 h) (P = 0.014), but declined more rapidly compared with prestorage filtered PC. A patient-based analysis including fewer cases revealed superior but nonsignificant results for bedside filtration. In conclusion, bedside filtered PC-BC resulted in better CCI results after short-term storage, but values equalized with prestorage filtered PC-BC after longer storage intervals. Prestorage-leucocyte filtration did not improve platelet recovery in vivo, but CCI values decreased only moderately throughout storage. Both preparations showed excellent transfusion results even after a 5-day storage interval.     

Reactions to platelet transfusion: the effect of the storage time of the concentrate

Random platelet concentrates were pooled and depleted of leucocytes by centrifugation immediately prior to transfusion. The incidence and severity of reactions to 570 leucocyte-poor platelet transfusions in 74 patients were studied. An overall transfusion reaction rate of 13.7% was observed. The reaction rate to platelets stored for less than 3 days (8.7%) was significantly different from the reaction rate to platelets stored for 3 days or more (17.6%). Minor reactions as well as moderate and severe reactions were more frequent in the latter group. As most of the white blood cells were removed prior to transfusion, it is suggested that the reactions result from the transfusion of pyrogenic and/or vasoactive substances accumulated in the plasma of the concentrate during storage.     

Therapeutic efficacy of pooled buffy-coat platelet components prepared and stored with a platelet additive solution

Despite the introduction of platelet additive solutions for the preparation of pooled platelet components, only a few studies of limited scope have evaluated the clinical efficacy of platelets stored in these solutions. The current report presents an analysis of data to evaluate the response to the transfusion of pooled buffy-coat components suspended in storage solution with reduced (35%) plasma content in comparison with 100% plasma products. During the euroSPRITE clinical trial of platelet components treated with a pathogen inactivation process, control treatment group platelet components were prepared in 100% allogeneic donor plasma (plasma control) or in platelet additive solution (T-Sol) mixed with plasma (T-Sol control). Control group thrombocytopenic patients received either plasma control or T-Sol control platelet components. One-hour and 24-h platelet count increments (CIs) and corrected count increments (CCIs) were analysed for these two types of preparation. In addition, haemostatic assessments were conducted for each transfusion. One-hour and 24-h mean platelet CIs and post-transfusion haemostatic scores were not significantly different for patients receiving platelet components suspended in 100% plasma and T-Sol plasma mixtures. Pooled buffy-coat platelet components prepared in reduced plasma content mixtures provided therapeutic platelet CIs with effective haemostasis.     

Transfusion outcome for volume- and plasma-reduced platelet concentrates for pediatric patients

Background and ObjectivesPlasma reduction in platelet concentrate (PC) products has been reported to prevent large volume load and transfusion-related adverse reactions (TRARs). However, volume reduction might be associated with a poor transfusion response because of a deterioration in platelet (PLT) quality. Because PLT quality control and transfusion responses for recently washed PCs using PLT additive solutions are superior, we investigated the clinical safety and transfusion efficacy of volume-reduced washed PCs in pediatric patients.Materials and MethodsWe prepared a simplified resuspended PC product (RPC) as a washed PC. Regular RPC (R-RPC) included equivalent volumes of bicarbonate Ringer's solution and anticoagulant citrate dextrose solution A (BRS-A) as the resuspension solution. Half RPC (H-RPC) was prepared by adding a half volume of BRS-A. Twenty-four pediatric patients were scheduled for transfusions with R-RPC and H-RPC up to 4 times. R-RPC was transfused 42 times into 24 patients. H-RPC was transfused 41 times into 23 patients.ResultsNeither product was observed to cause TRARs. Although the calculated PLT recovery for H-RPC was significantly reduced, the posttransfusion corrected count increment (24 h) did not differ. Moreover, similar results were observed for vital signs during transfusion.ConclusionVolume-reduced washed PC can be transfused without causing TRARs, differences in vital signs, or inferior transfusion responses. Volume-reduced washed PC also provides the advantages of shortened transfusion times and reduced volume loads. Although a standard technique for stable resuspension is necessary, volume-reduced washed PC may be a beneficial option for children, including neonates, or individuals with cardiovascular or renal problems.     

Role of mitochondria in the maintenance of platelet function during in vitro storage

Aims/Objectives: Platelets undergo structural and biochemical alterations during in vitro storage and these are collectively called platelet storage lesions (PSL). The mitochondrion is an important cell organelle involved not only in energy production but also in the regulation of cellular functions and viability. This implies that some platelet functions may be regulated by mitochondria; hence, preservation of mitochondrial functions may be important for the maintenance of platelet quality in stored platelet concentrates (PCs). This work describes the effects of various compounds on mitochondrial functions important for the maintenance of platelet quality in in vitro stored PCs. Methods: PCs were stored at 22 °C with gentle agitation in the presence or absence of 2,4‐dinitrophenol, antimycin A, acetyl‐l ‐carnitine and ascorbic acid. The effects of these products on platelet quality were assessed by analysing glucose and lactate concentrations, pH of the storage medium, shape of the platelets, mitochondrial membrane potential and depolarisation, surface expression of CD62P and collagen‐induced platelet aggregation. Results: 2,4‐Dinitrophenol and antimycin A increased PSL levels, whereas acetyl‐l ‐carnitine reduced the level of changes in pH and mitochondrial depolarisation. Ascorbic acid in the storage medium resulted in improved levels of collagen‐induced platelet aggregation. However, none of the examined reagents suppressed CD62P expression in platelets. Conclusions: These results suggest that preservation of mitochondrial function is fundamental, but not fully sufficient, for the maintenance of platelet in vitro quality during storage. Further research is necessary to develop methods for preserving both mitochondrial and platelet functions in in vitro stored PCs.     

Survey of the use and clinical effectiveness of HPA-1a/5b-negative platelet concentrates in proven or suspected platelet alloimmunization

The optimal treatment of neonatal alloimmune thrombocytopenia (NAIT) is the transfusion of compatible donor platelets. The National Blood Service in England has established panels of "accredited" donors negative for human platelet antigens HPA-1a and HPA-5b, the most commonly implicated alloantigens. We have retrospectively surveyed the frequency of use and clinical effectiveness of donations collected over a 13-month period from the Oxford accredited panel. Ninety-five per cent of hyperconcentrated platelets (HPCs) collected were issued, all for intrauterine transfusion to fetuses at risk of NAIT due to the presence of maternal platelet alloantibodies and previously affected siblings. Thirty-one per cent of paediatric platelet concentrates (PPCs) collected were issued, of which 57% were used for cases of suspected NAIT. Fifty-four per cent of adult therapeutic doses collected were issued; 5% of these were used in cases of suspected NAIT or proven post-transfusion purpura (PTP). Good increments were seen in most NAIT cases transfused with HPCs or PPCs, and a moderate increment in the one PTP case. We conclude that the establishment of accredited panels is justified and enables delivery of a clinically effective treatment for NAIT. Increased use and cost-effectiveness could be achieved by the delivery of an educational programme to neonatal unit clinical staff to increase the awareness and appropriate treatment of NAIT.     

改良白膜法制备浓缩血小板及回收率的影响因素

背景：白膜法和富含血浆法制备的浓缩血小板有无效输注发生率高和不良反应发生率高的缺点。 目的：观察改良白膜法制备浓缩血小板的实验研究,分析制备浓缩血小板回收率的影响因素。 方法：随机抽取126例站内采集后4-6 h的400 mL血液,随机分成改良白膜法组、白膜法组和富含血浆法组。改良白膜法采用3步离心,第1次采用次重离心,离心转速2300 r/min,离心时间12 min,降速5,离心温度（22±2）℃;第2次采用轻离心,离心转速910 r/min,离心时间10 min,离心温度（22±2）℃;第3次离心转速2800 r/min,离心时间12 min,离心温度（22±2）℃,离心后,挤去上层含血小板较少的血浆,袋中留30 mL血浆悬浮血小板,即为浓缩血小板。通过数据库文献检索的方法分析制备浓缩血小板回收率的影响因素。 结果与结论：改良白膜法、白膜法以及富含血浆法制备的手工浓缩血小板中,制备前各组血小板总数差别无统计学意义（P 〉0.05）;富含血浆法组和改良白膜法组较白膜法组血小板回收率高,差异有显著性意义（P 0.05）;白膜法组和改良白膜法组较富含血浆法组残留红细胞和残留白细胞的量少,差异有显著性意义（P0.05）。制备浓缩血小板的回收率受到全血量、离心转速、离心时间、离心方法等因素的影响。改良白膜法制备浓缩血小板减少红细胞和白细胞的残留量,提高了血小板的回收率,可在血液中心或中心血站推广应用。     

血小板输注前检测人类白细胞抗原抗体的必要性探讨

目的 探讨血小板输注前检测人类白细胞抗原(HLA)抗体的必要性.方法 对106例血小板输注无效患者检测其人类白细胞抗原抗体,以同样多次输血而再次输注血小板有效者作为对照. 结果实验组中HLA 同种抗体阳性52例(49.05%),对照组阳性13例(10.66%),两组比较差异有统计学意义(χ2= 6.689,P<0.01).结论 对于输血患者,特别是多次输血患者,开展HLA抗体筛查是非常必要的,另外,对于血小板输注无效的患者,还应开展血小板配型.     

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.     

Monitoring of platelet morphology during storage of platelet concentrates

During storage, human platelet concentrates progressively lose the capacity to survive and function in vivo after transfusion. A shape transformation from disc to sphere is the most reliable in vitro determinant for the loss of the in vivo survival of platelets. To find an objective measurement for platelet morphology, we studied the effect of anticoagulant, temperature, and storage on the apparent median platelet volume (MPV) as determined by a particle counter and on changes in platelet shape as measured and by light microscopy. Changes in MPV, light transmission, and morphology score by light microscopy were observed within 1 minute after collection of blood in CPDA. As compared to blood immediately fixed on withdrawal, in CPDA blood, the MPV increased from 4.1 to 5.7 fl, and light transmission difference decreased from 22 to 7 percent. A partial restoration of these determinants was found when the whole blood was incubated for 30 minutes at 37 degrees C, before preparation of platelet-rich plasma. In the first 5 days of platelet storage, the MPV increased from 4.6 to 5.0 fl; thereafter, it started to decrease. An increase in fragmented platelets after 5 days was observed on light microscopy. The light transmission difference showed a slow disc-to-sphere transformation during storage. This transformation accelerated from Day 5 to Day 7; after 11 days, only spheres were detected. After 7 days the swirling pattern scores were still in accordance with the presence of discs, whereas the other structure-associated determinants showed already spheric and even fragmented platelets.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impedance aggregometric analysis of platelet function of apheresis platelet concentrates as a function of storage time

Multiple electrode (impedance) aggregometry (MEA) allows reliable monitoring of platelet function in whole blood. The aims of the present study were to implement MEA for analyzing aggregation in platelet concentrates and to correlate results with storage time and blood gas analysis (BGA). We investigated the influence of platelet counts, calcium concentrations and agonists on platelet aggregation. Samples of apheresis concentrates up to an age of 12 days were investigated by MEA and BGA. For ASPI- and TRAPtest MEA was reproducible for a platelet count of 400 per 10^?9?L and a calcium concentration of 5?mmol L^?1. Platelets at the age of 2–4 days yielded steady aggregation. Platelet concentrates exceeding the storage time for transfusion showed steady aggregation up to 10 days, but a significant decline on day 12. Weak correlation was found regarding pCO₂ and MEA as well as regarding glucose concentration and MEA. Our results indicate that MEA is applicable for evaluation of aggregation in stored apheresis concentrates. Prolonged storage seems not to be prejudicial regarding platelet aggregation. Platelet concentrates showed acceptable BGA throughout storage time. Further studies are required to evaluate the application of MEA for quality controls in platelet concentrates.     

Effect of extending the platelet storage time on platelet utilization: predictions from a mathematical model of prophylactic platelet support

Bacterial culturing (BCU) or photochemical treatment (PCT) of platelet (PLT) concentrates may permit extending the storage time to 7 days at the cost of decreased viability of transfused PLTs. This study was aimed at predicting the impact this may have on the routine management of patients on prophylactic PLT support. The method included a mathematical model that represents the dynamics of prophylactic PLT support with standard, BCU or PCT PLTs. Data on posttransfusion PLT kinetics and the effect of PCT or storage time on PLT recovery and survival were obtained from published studies. Variables that influenced the level of PLT usage were the proportion of transfusions supplied with PLT on the last day of shelf-life, the use of PCT and the assumed degree of synergy between clinical factors of PLT consumption and either PCT or storage time. In the reference-case scenario, extending the PLT shelf-life to 7 days by BCU or PCT increased by 9 and 19%, respectively, the number of PLT transfusions per patient-year. In the worst-case scenario, these figures rose to 27 and 38%, respectively. Despite more intensive PLT usage, in most scenarios, the time that patients spent at PLT counts <10 x 10(9) L(-1) increased. Extending the shelf-life of PLT products will increase PLT usage. Such increase may be disproportionately larger for patients with complex conditions if there is a synergic interaction between storage time or PCT and clinical factors of PLT consumption, an issue that is worth further clinical research.