Storage of platelet concentrates from pooled buffy coats made of fresh and overnight-stored whole blood processed on the novel Atreus 2C+ system: in vitro study

BACKGROUND: The Atreus 2C+ system (Gambro BCT) automatically separates whole blood (WB) into buffy coat (BC), red blood cells (RBC), and plasma and transfers the components into separate containers. After processing with the Atreus, 4 to 6 BC units can be pooled and processed into leukoreduced platelets (PLTs) by use of the automated OrbiSac BC system (Gambro BCT). The aim of our in vitro study was to investigate the effects of holding either WB or BC overnight before preparation of PLTs by use of the Atreus 2C+ system for BC preparation. A standard routine procedure involving conventional blood containers for the preparation of BC combined with the OrbiSac process (top-and-top system; Terumo) was used as a reference. STUDY DESIGN AND METHODS: WB was either processed within 8 hours after collection ("fresh blood") or stored overnight before processing. WB units were separated into BC, RBC, and plasma units and transferred into individual containers. Either the BC or the WB units rested overnight at 22 +/- 2 degrees C. Six ABO-identical BCs, obtained from either fresh or overnight-stored WB, were pooled and processed with the OrbiSac BC system to obtain leukoreduced PLTs. In total, 20 Atreus and 10 reference (leukoreduced PLTs) samples were analyzed for various in vitro variables during the 7-day storage period. RESULTS: No significant difference in glucose consumption, lactate production, mean PLT volume, LDH activity, bicarbonate, ATP, RANTES, and the expression of CD62p and CD42b between groups was detected. pH was maintained at greater than 7.0 (Day 7). Swirling remained at the highest levels (score, 2) for all units throughout storage. CONCLUSION: PLTs derived from BCs, obtained from either fresh or overnight-stored WB processed on the novel automated Atreus 2C+ system, were equivalent to control PLTs with regard to PLT in vitro characteristics during 7 days of storage. Stable recovery of PLTs and satisfactory PLT content according to current standards were also found.     

Blood components produced from whole blood using the Atreus processing system

BACKGROUND: The Atreus 2C+ system (Gambro BCT) automates whole blood (WB) processing into a single device. This study compared the quality of red blood cells (RBCs), fresh‐frozen plasma (FFP), and buffy coats (BCs) made from WB held with or without active cooling. STUDY DESIGN AND METHODS: WB was collected into Atreus disposables and stored with (n = 20) or without (n = 20) active cooling for 14 to 18 hours at 22 ± 2°C before processing with the Atreus. Two RBC leukodepletion filters were assessed, and markers of RBC quality were tested to Day 42. BCs were held for 3 hours before testing, plasma was tested, and samples were frozen for coagulation analysis. RESULTS: RBCs met UK specifications for volume, hemoglobin content (48 ± 5 g), and hematocrit (Hct). Hemolysis, adenosine triphosphate, 2,3‐diphosphoglycerate, potassium, glucose, and lactate throughout storage were all within expected ranges. No differences were seen in RBC produced from WB held with or without active cooling. FFP units met UK specification for volume, total protein, cellular contamination, and coagulation factors. No differences were seen in FFP produced from WB held with or without active cooling. The Hct of BCs produced from WB held without active cooling was lower than in BCs from WB held with active cooling; no differences in activation were seen. CONCLUSION: From these in vitro data, blood components produced using the Atreus appear suitable for clinical use, with no clinically significant difference in the quality of components from WB held at ambient temperature overnight with or without active cooling.     

Platelet concentrates prepared after a 20- to 24-hour hold of the whole blood at 22°C

BACKGROUND: The Food and Drug Administration (FDA) requires that red blood cells must be refrigerated within 8 hours of whole blood collection. Longer storage of whole blood at 22°C before component preparation would have many advantages. STUDY DESIGN AND METHODS: Two methods of holding whole blood for 20 to 24 hours at room temperature were evaluated, refrigerated plates or a 23°C incubator. After extended whole blood storage, platelet (PLT) concentrates were prepared from PLT‐rich plasma on Day 1 postdonation, and the PLTs were stored for 6 more days. On Day 7 of PLT storage, blood was drawn from each subject to prepare fresh PLTs. The stored and fresh PLTs were radiolabeled and transfused into their donor. RESULTS: Eleven subjects' whole blood was stored using refrigerated butanediol plates (Compocool, Fresenius), and 10 using an incubator. Poststorage PLT recoveries averaged 47 ± 13% versus 53 ± 11% and survivals averaged 4.6 ± 1.7 days versus 4.7 ± 0.9 days for Compocool versus incubator storage, respectively (p = NS). With all results, poststorage PLT recoveries averaged 75 ± 10% of fresh and survivals 57 ± 13% of fresh; PLT recoveries met FDA guidelines for poststorage PLT viability but not survivals. CONCLUSION: Seven‐day poststorage PLT viability is comparable when whole blood is stored for 22 ± 2 hours at 22°C using either refrigerated plates or an incubator to maintain temperature before preparing PLT concentrates.     

In vitro and in vivo evaluation of a whole blood platelet‐sparing leukoreduction filtration system

BACKGROUND: In‐line leukoreduction (LR) filters decrease adverse clinical sequelae caused by residual white blood cells (WBCs). Such filtration, however, can remove platelets (PLTs) needed for production of PLT concentrates (PCs). This study measured in vitro and in vivo efficacy of a new whole blood PLT‐sparing LR filter (WBPSF) system that performs whole blood (WB) LR using a single closed‐system filtration step. The WBPSF provides three final LR products: AS‐5 red blood cells (RBCs), citrate‐phosphate‐dextrose (CPD) PLTs, and CPD plasma. STUDY DESIGN AND METHODS: Volunteers (n = 59) donated WB processed using the WBPSF system. WB filtration time was recorded, and LR WB was processed into AS‐5 LR RBCs, CPD LR PLTs, and LR plasma. Final components were assayed for in vitro indices, and in vivo characteristics for LR AS‐5 RBCs and CPD PLTs were assayed after radiolabeling. RESULTS: WB filtration time averaged 37 minutes. Transfusion products obtained after WBPSF met all in vitro and in vivo Food and Drug Administration (FDA) requirements. Radiolabeling of LR AS‐5 RBCs after WBPSF showed a 24‐hour RBC recovery of 81.3 ± 5.3% after 42 days of storage. In vivo dual ¹¹¹In/⁵¹Cr radiolabeling of PCs manufactured using WBPSF showed a Day 5 recovery ratio of 80 ± 19% versus fresh autologous PLTs and a survival ratio of 81 ± 17% that of fresh autologous PLTs. CONCLUSION: All WBPSF‐derived transfusion products met or exceeded in vitro and in vivo FDA guidelines. This filtration system is suitable for routine blood center or hospital use in the production of LR AS‐5 RBCs, CPD PLTs, and CPD plasma.     

Characterization of blood components separated from donated whole blood after an overnight holding at room temperature with the buffy coat method

BACKGROUND: With buffy coat (BC) processing of whole blood (WB) donations, increase in WB storage time to facilitate overnight holding before the separation of blood components would be a logistically attractive development. This study undertakes a comparative in vitro characterization of blood components prepared from WB samples that were either processed within 8 hours or stored overnight at room temperature before processing by the BC method. STUDY DESIGN AND METHODS: The WB units (400 mL) collected were either processed within 8 hours (fresh blood) or stored overnight (overnight blood) at room temperature. WB units were separated into individual‐component red blood cells (RBCs), BC, and plasma. The in vitro quality of these blood components (RBCs, pooled platelet concentrates [PCs], and plasma) was analyzed during storage. RESULTS: Levels of 2,3‐diphosphoglycerate (2,3‐DPG) were found to be significantly lower immediately after processing, compared with the fresh WB samples, in RBCs that had been separated from an overnight‐hold sample. However, this difference was not apparent after 14 days of storage. In pooled PCs, measurements for glucose, lactate, PO₂, PCO₂, extent of shape change, and hypotonic shock response were similar. The platelet yield in PCs prepared from an overnight‐hold WB sample was significantly higher, while CD62P expression and annexin V binding were lower (p < 0.05). For frozen plasma (FP), no significant differences were observed for the coagulation factors (F)II, FVII, FV, F IX, FX, and FXI; fibrinogen; and von Willebrand factor content between the 8‐ and 24‐hour FP. The FVIII was the component that was most sensitive to the prolongation of production time and it only had 80% of the activity of the 8‐hour FP. CONCLUSION: These data suggest that blood components (RBCs, pooled PCs, and FP) separated from WB that has been stored overnight at room temperature by the BC method are of acceptable quality.     

Recovery, survival, and function of transfused platelets and detection of platelet engraftment after allogeneic stem cell transplantation

BACKGROUND: Recovery and survival of transfused platelets (PLTs) are usually assessed by radioisotope labeling methods for evaluation of transfusion efficacy and new progress in the processing of PLT concentrates. Alternative, nonradioactive methods are warranted. STUDY DESIGN AND METHODS: A multicolor flow cytometry method was developed for simultaneous studies of recovery, survival, and function of transfused PLTs. Eight consecutive patients undergoing allogeneic stem cell transplantation (TX) were transfused with apheresis PLTs of nonself human leukocyte antigen (HLA) Class I types, and HLA Class I discrepancy between donor and recipient was used to identify transfused PLTs. Hematologic status and HLA Class I surface expression were analyzed immediately before transfusion, 1 and 6 hours after transfusion, and daily during the subsequent week. PLT activation was assessed by surface expression of CD63, CD62P, or CD42a, before and after stimulation with thrombin receptor agonist peptide. RESULTS: PLT recovery was 43, 41, and 31% for fresh (5‐72 hr old) and 30, 27, and 17% for stored (73‐148 hr old) PLTs, after 1, 6, and 15 to 28 hours, respectively. Survival of fresh versus stored PLTs were 160 and 105 hours, respectively. Spontaneous PLT activation and residual activation potential were almost equal for fresh and stored PLTs. PLT engraftment was detected between Day 7 and Day 9, which was significantly earlier than first sign of neutrophil engraftment (Days 11‐19; p = 0.01). CONCLUSION: Flow cytometry is an attractive alternative to radiolabeling of PLTs for simultaneous studies of survival, recovery, and function of transfused PLTs and early detection of PLT engraftment after allogeneic stem cell TX.     

Function of platelets in apheresis platelet concentrates and in patient blood after transfusion as assessed by Impact‐R

BACKGROUND: Platelet (PLT) transfusion is a mainstream therapy for preventing or treating bleeding episodes in patients with thrombocytopenia. The efficacy is usually estimated from the corrected count increment of PLTs after transfusion, which does not assess PLT function. We therefore evaluated PLT function in blood samples of patients with thrombocytopenia before and after transfusion. STUDY DESIGN AND METHODS: PLT function was assessed in 24 chemotherapy‐treated patients and in the PLT concentrates (PCs) by the Impact‐R (DiaMed). This device evaluates PLT adhesion and aggregation recorded as surface coverage (%) and size of aggregates (AS µm²). P‐selectin expression was determined by flow cytometry. RESULTS: The PCs were stored for a median of 70 hours before transfusion. An analysis stratified by the median storage of PCs (<70 hr or >70 hr) showed no differences in the SC, the AS, and P‐selectin expression between these concentrates' groups. Transfusion resulted in an increase of adhering PLTs in the patients after transfusion. There were no differences in the AS and in P‐selectin expression before and after transfusion, but the AS increased after transfusion upon ex vivo exposure to adenosine 5′‐diphosphate. P‐selectin expression was significantly lower in the patient group receiving PCs stored for more than 70 hours. CONCLUSION: The current trial shows the feasibility of using the Impact‐R to assess the function of transfused PLTs in the patient's blood stream.     

Transfusion-related immunomodulation by platelets is dependent on their expression of MHC Class I molecules and is independent of white cells

BACKGROUND: Transfusion‐related immunomodulation (TRIM) has been correlated with the presence of white cells (WBCs) in blood transfusions, but the role of components such as platelets (PLTs) in mediating TRIM has not been extensively examined. We designed a murine PLT transfusion model to study whether leukoreduced PLTs mediate TRIM effects. STUDY DESIGN AND METHODS: CBA recipient mice were administered four weekly transfusions of either fresh (4 hr) or aged (24 and 72 hr) donor leukoreduced PLTs from allogeneic BALB/c mice and then transplanted with skin grafts from donor‐matched mice. TRIM was measured by comparing the times to graft rejection and these were correlated with immunoglobulin G (IgG) antibody development measured by flow cytometry. RESULTS: Compared with nontransfused control recipients, four transfusions of fresh, extremely leukoreduced (<0.05 WBCs/mL), allogeneic PLTs significantly (p < 0.002) reduced the recipient's ability to reject donor‐matched skin grafts (survival >49 days compared with <14 days in nontransfused controls) despite the presence of high‐titered serum IgG donor antibodies. In contrast, however, aged PLTs or fresh PLTs devoid of MHC Class I molecules were unable to affect skin graft survival nor stimulate antibody production. The PLT age‐related inability to induce TRIM was shown to be due to loss of PLT‐associated MHC Class I molecules; soluble supernatant MHC molecules that were transfused were unable to induce TRIM. CONCLUSION: These results suggest that fresh PLTs can induce TRIM independently of WBCs due to their MHC antigen expression whereas aging results in loss of MHC and ability to mediate TRIM. The findings support the concept that either active MHC removal from fresh PLTs or passive removal by, for example, storage, may reduce any deleterious effects of TRIM in transfusion recipients.     

Storing apheresis platelets without agitation with simulated shipping conditions during two separate periods: immediately after collection and subsequently between Day 2 and Day 3

BACKGROUND: Apheresis platelet (PLT) units are not routinely agitated during transit. Our study compared the in vitro properties of apheresis PLT units that were stored with continuous agitation (CA) and without continuous agitation (WCA) during two separate periods, immediately after collection and between Day 2 and Day 3 of storage. STUDY DESIGN AND METHODS: Two identical apheresis PLTs units were prepared from collections with Amicus (n = 11, Fenwal, Inc.) and Trima (n = 10, CaridianBCT) cell separators. One apheresis PLT unit was continuously agitated, starting routinely within 30 minutes of collection, and an identical apheresis PLT unit was held without agitation initially for 7 to 8 hours and subsequently for 24 hours between Day 2 and Day 3 of storage. The apheresis PLT units were maintained WCA at 20 to 24°C in a shipping box. In vitro PLT properties were evaluated on Day 1 (day after collection), after 5 and 7 days of storage. RESULTS: With both Amicus and Trima apheresis PLT units, the mean PLT content and concentration of CA and WCA were comparable and essentially constant throughout storage. Mean pH levels (±1 SD) after 5 days for Amicus apheresis PLT units were 6.97 ± 0.20 (WCA) and 7.13 ± 0.16 (p < 0.001, CA) and for Trima apheresis PLT units 6.97 ± 0.21 (WCA) and 7.22 ± 0.17 (p < 0.001, CA). In vitro variables, including percentage of disc PLTs, extent of shape change, and hypotonic stress levels, after 5 days of storage, showed mean differences between WCA and CA that were less than 15%. CONCLUSION: The in vitro results show that apheresis PLT units can be stored without agitation for 7 to 8 hours immediately after collection and also subsequently during storage for 24 hours with minimal influence on in vitro PLT properties compared to continuously agitated PLTs.     

Interruption of agitation of platelet concentrates: a multicenter in vitro study by the BEST Collaborative on the effects of shipping platelets

BACKGROUND: Transported platelets (PLTs) are not under continuous agitation. The aim of this study was to determine whether PLTs shipped between 24 and 48 hours would be able to maintain a pH(22 degrees C) value of 6.5 at the end of 7 days of storage. STUDY DESIGN AND METHODS: Six laboratories prepared leukoreduced PLTs. PLT pools were divided into low and high PLT concentration with paired shipped (20-43 hr) and unshipped controls. Units were under continuous agitation at 22 +/- 2 degrees C when not being transported. In vitro measures including pH, pO(2), and pCO(2) were determined over 7 days. RESULTS: Ninety-two PLT components from 24 pools were eligible for analysis. One unshipped control and three shipped products failed to maintain a pH(22 degrees C) value of 6.5 through 7 days. In vitro characteristics were maintained slightly better over 7 days of storage in the unshipped control arms. PLT concentration, shipping time, and their interaction were significant determinants of the final pH at the end of storage (p < 0.05). Lactate generation rate increased by 35 +/- 2 (mean +/- SE) micromol per 10(12) PLTs per hour over baseline during shipping (p < 0.0001). After restoration of standard blood banking conditions with agitation, this rate dropped 24 +/- 2 micromol per 10(12) PLTs per hour (p < 0.0001). CONCLUSION: PLTs in plasma shipped for at least 20 to 24 hours maintain a pH(22 degrees C) value of 6.5 for 7 days. A longer shipping time may result in a pH(22 degrees C) value of 6.5. During shipping, glycolysis was up regulated in these PLTs resulting in increased lactic acid production. After restoration of agitation, shipped products down regulated glycolysis. These effects should be accounted for in the development of PLT storage and transportation systems.     

Assessing the effectiveness of whole blood-derived platelets stored as a pool: a randomized block noninferiority trial

BACKGROUND: Prestorage pooling of whole blood-derived platelets (PLTs) would simplify bacterial detection. This study evaluated the in vivo effect of the prestorage pooling of PLTs stored for up to 5 days, by assessing the corrected count increment (CCI) 18 to 24 hours after transfusion of the product. STUDY DESIGN AND METHODS: A randomized block noninferiority design was used. Eligible patients had chemotherapy-induced thrombocytopenia and were considered likely to need at least six PLT transfusions. For every block of two transfusion events, one consisted of PLTs stored individually and then pooled before transfusion, and the other was a product pooled before storage. The primary outcome was categorized as a successful (>4.5) or unsuccessful (相似文献   

The influence of conditions utilized to hold apheresis and whole blood–derived platelet samples before platelet enumeration with three hematology analyzers

BACKGROUND: The Advia 120 (Siemens Diagnostics) hematology analyzer is different from other hematology analyzers in that it requires platelets (PLTs) to be “effectively spherical” to be counted. Our study evaluated how PLT counts with this hematology analyzer and two other models were influenced by the holding of PLT product samples. STUDY DESIGN AND METHODS: Samples were prepared from apheresis PLT products (APs) collected in ACD‐A and from whole blood–derived PLT concentrates (PCs) in CP2D or ACD‐A. Samples were stored in K₂ and K₃ethylenediaminetetraacetate (EDTA) tubes at room temperature (RT) and in the cold. PLT counts were determined immediately, after 1 and 4 hours, and after an overnight hold, using Advia 120, XE‐2100D, and Cell‐Dyn 3700 hematology analyzers. RESULTS: A time‐dependent increase in PLT counts was observed with AP samples held at RT using the Advia 120, but not with the other two hematology analyzers. AP samples held in the cold did not show a substantial time‐dependent increase with any of the hematology analyzers. With the Advia 120, the PLT counts in the immediate samples were approximately 14% lower compared to those in cold or overnight‐held RT samples. PC samples with all holding conditions and hematology analyzers did not show any substantial time‐dependent increase in counts. CONCLUSIONS: With the Advia 120 hematology analyzer, the time‐dependent increase in PLT counts with RT‐held samples may be related to the need to have effectively sphered PLTs unlike that with the other two hematology analyzers. The absence of a holding effect with PC samples may indicate that only AP samples have population(s) that are slow to convert to spherical PLTs.     

Extended storage of platelet‐rich plasma–prepared platelet concentrates in plasma or Plasmalyte

BACKGROUND: Using bacterial detection or pathogen reduction, extended platelet (PLT) storage may be licensed if PLT viability is maintained. The Food and Drug Administration (FDA)'s poststorage PLT acceptance guidelines are that autologous stored PLT recoveries and survivals should be 66 and 58% or greater, respectively, of each donor's fresh PLT data. STUDY DESIGN AND METHODS: Nonleukoreduced PLT concentrates were prepared from whole blood donations. Autologous PLT concentrates from 62 subjects were stored in 100% plasma (n = 44) or 20% plasma/80% Plasmalyte (n = 18), an acetate‐based, non–glucose‐containing crystalloid solution previously used for PLT storage. Fresh PLTs were obtained on the day the donor's stored PLTs were to be transfused. The fresh and stored PLTs were alternately radiolabeled with either ⁵¹chromium or ¹¹¹indium, and in vitro measurements were performed on the stored PLTs. RESULTS: The FDA's PLT recovery criteria were met for 7 days of plasma storage, but PLT survivals maintained viability for only 6 days. Plasmalyte‐stored PLTs did not meet either acceptance criteria after 6 days of storage. After 7 days of storage, PLT recoveries averaged 43 ± 4 and 30 ± 4% and survivals 4.1 ± 0.4 and 2.0 ± 0.2 days for plasma‐ and Plasmalyte‐stored PLTs, respectively (p = 0.03 for recoveries and p < 0.001 for survivals). Poststorage PLT recoveries correlated with the commonly used in vitro PLT quality measurements of hypotonic shock response and annexin V binding, while survivals correlated with extent of shape change, morphology score, and pH. CONCLUSION: There is a progressive decrease in recoveries and survivals of plasma‐stored PLTs over time. PLT viability is better maintained in plasma than Plasmalyte.     

A randomized controlled trial comparing autologous radiolabeled in vivo platelet (PLT) recoveries and survivals of 7-day-stored PLT-rich plasma and buffy coat PLTs from the same subjects

BACKGROUND: A recent review concluded that there was inadequate evidence to show a difference between buffy coat (BC) and platelet (PLT)‐rich plasma (PRP) PLT concentrates prepared from whole blood. We hypothesized that 7‐day‐stored BC‐PLTs would have superior autologous recoveries and survivals compared to PRP‐PLTs and that both would meet the Food and Drug Administration (FDA) criteria for poststorage viability. STUDY DESIGN AND METHODS: This was a randomized, crossover study design in healthy subjects who provided informed consent. Each participant donated a unit of whole blood on two occasions. In random order, either BC‐PLTs or PC‐PLTs were prepared after a 20 ± 2°C overnight hold of the whole blood. PLTs were stored under standard conditions. On Day 7, fresh PLTs were prepared from 43 mL of autologous whole blood. The fresh PLTs paired with either BC‐PLTs or PRP‐PLTs were alternately labeled with ¹¹¹In or ⁵¹Cr and simultaneously reinfused to determine recoveries and survivals. In vitro assays were performed on Days 1 and 7. RESULTS: Fourteen subjects completed the study at two sites. No differences in poststorage PLT viabilities were observed between BC‐PLTs and PRP‐PLTs; recovery differences averaged 3.7 ± 2.4% (±SE, p = 0.15) and survival differences averaged 0.48 ± 0.56 days (p = 0.41). Neither type of PLTs met the current FDA criteria for either poststorage PLT recoveries or survivals. CONCLUSION: We were unable to demonstrate that single‐unit BC‐PLTs stored for 7 days have superior poststorage viability compared to PRP‐PLTs. Failure to meet the minimum FDA criteria for poststorage PLT viability raises questions regarding the acceptance thresholds of these metrics.     

The effect of whole-blood storage time on the number of white cells and platelets in whole blood and in white cell-reduced red cells

BACKGROUND: Whole blood (WB) can be stored for some time before it is processed into components. After introduction of universal white cell (WBC) reduction, it was observed that longer WB storage was associated with more residual WBCs in the WBC-reduced red cells (RBCs). Also, weak propidium iodide (PI)-positive events were observed in the flow cytometric WBC counting method, presumably WBC fragments. The effect of storage time on the composition of WB and subsequently prepared WBC-reduced RBCs was studied. STUDY DESIGN AND METHODS: WB was collected in bottom-and-top collection systems with inline filters, obtained from Baxter, Fresenius, or MacoPharma. Units were stored at room temperature and separated into components in 4-hour intervals between 4 and 24 hours after collection. RBCs were WBC-reduced by inline filtration (approx. 50/group). RESULTS: Platelet (PLT) counts were lower in WB stored for 4 to 8 hours compared to 20 to 24 hours (mean +/- SD): 79 +/- 31 versus 102 +/- 30 for Baxter (p < 0.01); 91 +/- 31 versus 101 +/- 35 for Fresenius (not significant); and 73 +/- 47 versus 97 +/- 31 (all x 10(9) per unit) for MacoPharma (p < 0.01), respectively. The median residual WBC counts in WBC-reduced RBCs for WB stored for 4 to 8 and 20 to 24 hours were 0.03 versus 0.17 for Baxter (p < 0.001), 0.00 versus 0.06 for Fresenius (p < 0.001), and 0.13 versus 0.26 (all x 10(6) per unit) for MacoPharma (not significant), respectively. All WBC-reduced RBCs contained fewer than 5 x 10(6) WBCs per unit. A longer storage time of WB was associated with more weak PI-positive events, irrespective of the filter. CONCLUSION: Longer storage of WB before processing results in counting higher numbers of PLTs in WB, higher numbers of WBCs in WBC-reduced RBCs, and more weak PI-positive events.     

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.     

Temperature cycling improves in vivo recovery of cold‐stored human platelets in a mouse model of transfusion

BACKGROUND: Platelet (PLT) storage at room temperature (RT) is limited to 5 days to prevent growth of bacteria, if present, to high levels. Storage in cold temperatures would reduce bacterial proliferation, but cold‐exposed PLTs are rapidly cleared from circulation by the hepatic Ashwell‐Morell (AM) receptor, which recognizes PLT surface carbohydrates terminated by β‐galactose. We cycled storage temperature between 4 and 37°C to preserve PLT function and reduce bacterial growth. STUDY DESIGN AND METHODS: Temperature‐cycled (TC) human PLTs were stored at 4°C for 12 hours and then incubated at 37°C for 30 minutes before returning back to cold storage. PLTs stored at RT or at 4°C (COLD) or TC for 2, 5, and 7 days were infused into SCID mice and the in vivo recovery was determined at 5, 20, and 60 minutes after transfusion. RESULTS: PLTs stored for 2 days in COLD had significantly lower in vivo recoveries than RT PLTs. TC PLTs had improved recoveries over COLD and comparable to RT PLTs. After 5‐ and 7‐day storage, TC PLTs had better recoveries than RT and COLD PLTs. PLT surface β‐galactose was increased significantly for both COLD and TC PLTs compared to RT. Blocking of the AM receptor by asialofetuin increased COLD but not TC PLT recovery. CONCLUSION: TC cold storage may be an effective method to store PLTs without loss of in vivo recovery. The increased β‐galactose exposure in TC PLTs suggests that mechanisms in addition to AM receptors may mediate clearance of cold‐stored PLTs.     

In vitro variables of apheresis platelets are stably maintained for 7 days with 5% residual plasma in a glucose and bicarbonate salt solution, PAS-5

BACKGROUND: Platelet additive solutions (PASs) facilitate improved recovery of plasma and may reduce the severity and/or frequency of plasma‐associated transfusion reactions. Current apheresis platelet (PLT) PAS products contain approximately 30 to 40% residual plasma. In an effort to further decrease the residual plasma, two in vitro studies were conducted with PLTs suspended in 5% plasma and a reformulated PAS‐3, named PAS‐5, that contains additional salts, glucose, and bicarbonate. STUDY DESIGN AND METHODS: In Study 1, PLTs suspended in 5% plasma/95% PAS‐5 were prepared directly on a separator (Amicus, Fenwal, Inc.) without additional centrifugation or washing. In Study 2, a double unit of hyperconcentrated Amicus PLTs in plasma was collected, divided, and centrifuged to prepare a control unit in 100% plasma and a paired test unit in 5% plasma/95% PAS‐5. The in vitro properties of PLTs were assessed in both studies during 7‐day storage at 20 to 24°C with continuous agitation. RESULTS: In Study 1, PLT concentration, pH, mean PLT volume (MPV), HCO₃^‐, pCO₂, pO₂, lactate dehydrogenase, and hypotonic shock response (HSR) did not significantly change during storage. By Day 7, glucose levels and morphology scores modestly decreased (17.6 and 14.4%, respectively) and lactate levels modestly increased (to 7.2 mmol/L). In Study 2, MPV, pH, glucose, pO₂, HSR, and morphology were comparable in control and test PLTs during 7‐day storage. Glucose consumption and lactate production were significantly less in test versus control PLTs (p ≤ 0.0015). Extent of shape change and %CD62P‐positive test PLTs were less than those of controls (p < 0.001). CONCLUSION: Apheresis PLTs suspended in 5% plasma/95% PAS‐5 maintained in vitro properties during 7‐day storage.     

A randomized controlled trial evaluating recovery and survival of 6% dimethyl sulfoxide–frozen autologous platelets in healthy volunteers

BACKGROUND: Availability of platelets (PLTs) is severely limited by shelf life in some settings. Our objective was to determine and compare to Food and Drug Administration (FDA) criteria the PLT recovery and survival of autologous PLTs cryopreserved at ?65°C or less in 6% dimethyl sulfoxide (DMSO) reconstituted with a no‐wash method (cryopreserved PLTs [CPPs]) compared to autologous fresh PLTs. STUDY DESIGN AND METHODS: This was a randomized, Phase I study analyzing PLT viability and in vitro function in consenting healthy subjects. Apheresis PLTs (APs) were collected in plasma. APs were suspended in 6% DMSO, concentrated, and placed at not more than ?65°C for 7 to 13 days. Frozen CPPs were thawed at 37°C and resuspended into 25 mL of 0.9% NaCl. Control PLTs (fresh autologous) and CPPs were labeled with ¹¹¹In or ⁵¹Cr, and recovery and survival after reinfusion were determined using standard methods. A panel of in vitro assays was completed on APs and CPPs. RESULTS: After frozen storage, CPPs retained 82% of AP yield and showed increased PLT associated P‐selectin and reduced responses to agonists. CPP 24‐hour recovery (41.6 ± 9.7%) was lower than for fresh PLTs (68.4 ± 8.2%; p < 0.0001) and did not meet the current FDA criterion. CPPs had diminished survival compared to fresh PLTs (7.0 ± 2.1 days vs. 8.4 ± 1.2 days, respectively; p = 0.018), but did meet and exceed the FDA criterion for survival. CONCLUSION: While 24‐hour recovery does not meet FDA criteria for liquid‐stored PLTs, the CPP survival of circulating PLTs was surprisingly high and exceeded the FDA criteria. These data support proceeding with additional studies to evaluate the clinical effectiveness of CPPs.     

Effects of immediate or delayed addition of platelet additive solution on the in vitro quality of apheresis platelets

BACKGROUND: There is little knowledge how different hold times of hyperconcentrated platelet (PLT) suspensions (HPSs) before the addition of platelet additive solution (PAS) might affect PLT quality. We compared the in vitro quality of single‐donor PLT concentrates (SDPs) with immediate or delayed PAS addition and studied the quality of collected concurrent plasma (CP). STUDY DESIGN AND METHODS: We collected 6 × 10¹¹ PLTs in 175 of mL plasma and CP from 31 donors. The HPSs were split into two parts, with 162 mL of modified PAS III (PAS‐IIIM) added immediately (0hr‐SDP) or 2 hours later (2hr‐SDP). Final SDPs had a targeted concentration of 1.2 × 10¹² PLTs/L and a PAS proportion of 65%. On Days 1, 5, and 7 we determined glucose and lactate concentration, pH, P‐selectin expression, hypotonic shock response (HSR), and extent of shape change (ESC). Clotting Factor V (FV) and VIII (FVIII) activities and D‐dimer concentration were determined in CP and donor. RESULTS: Glucose utilization, lactate production, and pH were similar for both kinds of products. Low P‐selectin expression indicated no relevant PLT activation during storage. HSR and ESC were similarly well preserved. Recoveries of FV and FVIII were 100.0 ± 14.0 and 98.6 ± 14.9%, respectively. Concentrations of D‐dimers in the donor and CP were 173.7 ± 90.1 and 177.6 ± 91.2 ng/dL, respectively. CONCLUSIONS: Adding PAS immediately or 2 hours after collection does not result in different in vitro quality of PLTs stored up to 7 days. The good recovery of clotting factors with no signs of activation indicates a good quality of CP.