In vitro evaluation of COM.TEC apheresis platelet concentrates using a preparation set and pathogen inactivation over a storage period of five days

The aim of the present study was to evaluate in vitro data on platelets collected by apheresis, processed on a preparation set followed by photochemical treatment (PCT). Fifteen single-donor platelet concentrates (PCs) were collected by apheresis (COM.TEC blood cell separator, Fresenius, Bad Homburg, Germany). The platelets were transferred to the preparation set and plasma was removed after centrifugation to resuspend the platelets in approximately 37% plasma and 63% platelet additive solution InterSol. PCT was done by exposing the platelets to amotosalen HCl followed by illumination with ultraviolet light. Blood cell counts and in vitro PLT function were measured up to 5 days. An average of 3.44 +/- 0.28 x 10(11) platelets were collected in a product volume of 351 +/- 21 mL. Plasma removal resulted in a mean platelet loss of 7.8%. After PCT, a progressive decrease in platelet function was observed. LDH level rose through storage (171 +/- 81 U/L) to levels approximating LDH levels observed post-collection (180 +/- 103 U/L). There was a gradual decrease of the platelets to respond to hypotonic shock response from 90 +/- 9 % post-plasma reduction to 48 +/- 16% at day 5. All PLT units met the European requirements for leukoreduction and the pH limit of 6.8 up to day 5 post-collection. The new preparation set was capable of producing platelet units meeting the requirements for PCT. Despite differences observed in in vitro platelet function parameters, PLTs at storage day 5 fit the German and European guidelines.     

Evaluation of a new whole-blood filter that allows preparation of platelet concentrates by platelet-rich plasma methods

BACKGROUND: A novel WBC-reduction in-line whole-blood (WB) filter that does not retain platelets was evaluated to assess the filtration performance and, after processing WB by the platelet-rich plasma (PRP) method, to analyze the storage quality of filtered platelet concentrate (PC) units. STUDY DESIGN AND METHODS: To analyze the filter retention, blood was collected from random donors into quadruple blood packs with an integral in-line filter (Imuflex WB-SP, Terumo; n = 25) or in standard triple bag systems (n = 30). To assess the in vitro storage characteristics of platelets, 26 WB units were pooled in pairs and redistributed into 13 units that underwent WBC reduction and 13 units that were not WBC reduced. In all cases, WB was separated into RBCs, PCs, and plasma by the PRP method and platelet function was compared. RESULTS: The filtration procedure led to RBC and PC WBC-reduced products that met the AABB and European requirements. The average filtration time was 30 minutes, the filter retained about 45 mL of WB, and there was no further loss of RBCs during the fractionation procedure. In vitro PC storage characteristics of the filtered units were similar to those of the nonfiltered units. CONCLUSION: A 4- and 3-log WBC reduction was observed in RBC and PC units that were produced by the PRP method, with a mean residual WBC content of 0.24 +/- 0.38 x 106 and 0.02 +/- 0.03 x 106 per unit, respectively. The procedure, performed under relatively simple logistics, results in good-quality, standard components that may reduce costs and ease the process of WBC reduction in transfusion services.     

Universal adoption of pathogen inactivation of platelet components: impact on platelet and red blood cell component use

BACKGROUND: Pathogen inactivation of platelet (PLT) components (INTERCEPT Blood System, Cerus Europe) was implemented into routine practice at a blood center supporting a tertiary care hospital. Utilization of platelet components (PCs) and red blood cell (RBC) components was analyzed for 3 years before and 3 years after introduction of pathogen inactivation to assess the impact of pathogen inactivation on component use.
STUDY DESIGN AND METHODS: This was a retrospective analysis of prospectively collected data. An electronic database used in routine blood bank hemovigilance to monitor production and use of blood components was analyzed to assess clinical outcomes.
RESULTS: Transfusion records were analyzed for 688 patients supported with conventional PCs and 795 patients supported with pathogen inactivation PCs. Additional analyses were conducted for intensively transfused hematology patients. Patient demographics (age category, sex, and diagnostic category) were not different in the two observation periods. For all patients, mean numbers of PC per patient were not different for conventional PCs and pathogen inactivation PCs (9.9 ± 19.5 vs. 10.1 ± 20.9, p = 0.88). Data for hematology patients (272 conventional PCs and 276 pathogen inactivation PCs) confirmed that days of PLT support were not different (31.6 ± 42.6 vs. 33.1 ± 47.9, p = 0.70) nor was total PLT dose (10¹¹) per patient (87.3 ± 115.4 vs. 88.1 ± 111.6, p = 0.93). RBC use, for all patients and hematology patients, was not different in the two observation periods, either during periods of PLT support or outside periods of PLT transfusion support.
CONCLUSION: Pathogen inactivation of PCs had no adverse impact on component use during a 3-year observation period of routine practice.     

Evaluation of platelet concentrates stored for 5 days with reduced plasma volume

BACKGROUND: Currently, platelet concentrates (PCs) are stored in a suspending plasma volume of 45 to 65 mL. Previous studies using second- generation containers indicated that PCs stored for 5 days at volumes less than 30 mL have reduced in vivo percentage recoveries as compared to PCs stored at volumes of 50 mL or more. STUDY DESIGN AND METHODS: This study has evaluated the effect of PC plasma volume on the maintenance of in vivo and in vitro platelet properties following 5 days of storage, with the purpose of establishing the minimum plasma volume in the range of 30 to 50 mL. Twenty paired studies were performed in which identical populations of platelets from the same donor (obtained by double manual apheresis) were stored in a normal volume (55-60 mL, control) and reduced volume (30-50 mL, test) of plasma. Comparison of in vivo viability between test and control PCs was performed after random radiolabeling of 1 unit with 51Cr and of the other with 111In, with simultaneous transfusion and with calculation of percentage recovery and the area below the survival curve (integral) as measures of viability. RESULTS: When test unit volumes were > or = 35 mL, essentially identical platelet survival curves and in vitro results were obtained for test and control. The integral and the percentage recovery for the test units were (mean, 95% confidence interval) 98.7 (96.3-101.0) and 99.0 percent (94.7-103.3) of those values in the control units, respectively. Test units with volume < or = 34 mL demonstrated reduced in vivo viability with integral and percentage recovery of 81.1 (68.9-93.3) and 80.4 (69.3-91.5), respectively, as compared to the control units. This loss was associated with increased metabolic activity (lactate production), which may suggest platelet activation due to the increased surface-to-PC volume ratio. CONCLUSION: These results show that the storage volume of PCs may be reduced from 50 to 60 mL to 35 to 40 mL without any significant decrease in in vivo or in vitro platelet quality.     

Functional characteristics of buffy-coat PLTs photochemically treated with amotosalen-HCl for pathogen inactivation

BACKGROUND: One blood system for PLTs (INTERCEPT, Baxter Transfusion Therapies) is based on photochemical treatment (PCT) with small molecules that target cross-link nucleic acids (Helinx technology, Cerus Corp.) with amotosalen-HCl (S-59) and UVA light (320-400 nm) to inactivate pathogens and WBCs. STUDY DESIGN AND METHODS: A two-arm in vitro study was conducted to compare pooled buffy-coat-derived PLT concentrates (PCs) treated with the INTERCEPT blood system, resuspended in PLT additive solution (PAS) III (InterSol, Baxter Transfusion Therapies), and stored for up to 7 days (test units, n = 20) with unpaired, nontreated PCs, resuspended in PAS II (T-Sol, Baxter Transfusion Therapies), and prepared at the same center in the same manner (control units, n = 18). RESULTS: PLT dose (x 1011/unit +/- SD) on Day 1 immediately following PCT was 3.0 +/- 0.4 for test units and 3.2 +/- 0.4 for control units. After 7 days of storage, the pH of all test units was maintained above 6.8. No marked trend was observed in the hypotonic shock response (HSR). Values among study groups were similar at the end of observation period: 68 +/- 11 percent for control unites versus 67 +/- 8 percent for test units (p > 0.05). Aggregation response to ristocetin was slightly lower in test units: at Day 7, 65 +/- 10 percent versus 76 +/- 6 percent (p < 0.05). Significantly higher (p < 0.001) glucose consumption, lactate production, and CD62P expression were observed in test units. CONCLUSION: Compared to nontreated PLTs, the PCT process was associated with a variety of differences of in vitro analyses. Although significant, these changes were relatively small in most cases. Characteristics correlated with survival in vivo such as HSR and swirling were comparable between both study groups, indicating that the viability of the majority of cells appears to have persisted throughout 7 days of storage. The impact of this finding, however, remains to be investigated in clinical trials performed with 7-day stored PLTs.     

Paired comparison of platelet concentrates prepared from platelet-rich plasma and buffy coats using a new technique with 111In and 51Cr

Two techniques for the preparation of platelet concentrate (PC), the standard platelet-rich plasma (PRP) and buffy coat (BC) methods, were compared in nine paired studies with regard to platelet harvest, white cell (WBC) contamination, and PC quality after 5 days of 22 degrees C storage. Platelet harvest using the BC method averaged approximately 56 percent of the whole blood level (6.2 x 10(10)/concentrate), which was less than the 76 percent achieved with the PRP-PC method (8.7 x 10(10)/concentrate). An additional 5 units collected into an experimental siphon bag for BC-PC processing showed improved platelet harvest (6.7 x 10(10)/concentrate, or approx. 70% of whole blood). WBCs remaining in the BC-PC averaged 0.19 x 10(8) per unit compared to 3.6 x 10(8) per unit for PRP-PC. Buffy coat processing produced red cell (RBC) units with 50 percent of the WBC contamination of conventionally prepared units (9.8 +/- 6.2 x 10(8)/unit vs. 18.9 +/- 7.1 x 10(8)/unit). The siphon bag further reduced WBC levels in the AS-3 RBC units (6.4 +/- 3.7 x 10(8)/unit). In vitro studies performed on Days 1 and 5 after collection showed no significant differences in platelet metabolic and biologic function or cell integrity. Beta-thromboglobulin and surface glycoprotein levels, indicators of platelet activation and membrane alteration, respectively, did not differ significantly in the PRP-PC and BC-PC; nor was lactate production higher in PRP-PC, despite the substantially higher WBC counts. Autologous in vivo platelet viability determinations were performed by using concurrent transfusion of 111In-labeled freshly drawn platelets and 51Cr-labeled stored platelets.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of additive solutions and pathogen inactivation treatment of platelet components in a regional blood center: impact on patient outcomes and component utilization during a 3‐year period

BACKGROUND: The Etablissement Français du Sang Alsace (EFS Alsace) successively implemented universal use of platelet additive solutions (PASs) and pathogen inactivation (PI) for platelet components (PCs). To assess the impact of these changes, EFS Alsace evaluated PC use, red blood cell (RBC) component use, and transfusion‐related adverse events after implementation of these new technologies. STUDY DESIGN AND METHODS: EFS Alsace prospectively collects data on production, distribution, and response to transfusion of all blood components with greater than 99.5% data acquisition. Adverse events attributed to platelet (PLT) transfusions were collected through a mandatory, active hemovigilance program. A retrospective review of prospectively collected data was conducted covering three periods: 1) apheresis and whole blood–derived PCs in plasma, 2) apheresis and whole blood–derived PCs with PAS, and 3) PCs prepared with PI and PAS. Data on component utilization were analyzed for all patients receiving PCs in each period and for the subset of hematology‐oncology patients to evaluate PC use in an intensely transfused population. Values for all continuous variables were summarized as mean and standard deviation, median, and range. RESULTS: Approximately 2000 patients received PCs in each period. PLT and RBC use per patient was not increased after PI (analysis of variance, F = 1.9 and 2.9, respectively) and the incidence of acute transfusion reactions was significantly reduced (p < 0.001). CONCLUSIONS: Universal use of PI was implemented without impacting component use, as indicated by total dose of PLTs per patient, and outcomes to transfusion were improved.     

Storage of platelet-rich plasma-derived platelet concentrate pools in plasma and additive solution

BACKGROUND: Prestorage pooling of platelet (PLT)-rich plasma (PRP)-derived PLT concentrates (PCs) and storage in either plasma (PS) or an additive solution (AS) is logistically feasible and would result in a product similar to buffy-coat or apheresis PLTs. STUDY DESIGN AND METHODS: On Day 0, PS PRP PCs were pooled with a sterile connecting device into a new 1.3-L storage container (ELX, PALL Medical). AS-PCs were prepared by addition of a new low-pH glucose-containing AS to the PLT sediment. AS-PCs were pooled into a 1.3-L ELX bag containing four tablets of NaHCO3. PC pools were sampled on Days 1, 5, and 7. RESULTS: PS pools containing 5 units had a mean PLT yield similar to the AS pools (39 x 10(10) +/- 3 x 10(10) vs. 37 x 10(10) +/- 6 x 10(10); p = 0.25). All pools had WBC counts of less than 1 x 10(6). pH and HCO3 decreased in PS pools with storage, but either increased or remained constant in the AS pools. On Day 7, no differences were seen in morphology score or extent of shape change. Hypotonic shock response was better preserved in the plasma pools (71 +/- 12% vs. 56 +/- 13%, p < 0.01); however, surface P-selectin was expressed less in the AS pools (6 +/- 4% vs. 18 +/- 10%, p < 0.01). CONCLUSION: Manufacture and storage of PRP-PCs in pools either in plasma or in a glucose-containing AS in this new container are feasible, and there is good preservation of PLT quality to Day 7.     

Bacterial contamination of platelet concentrates: results of a prospective multicenter study comparing pooled whole blood-derived platelets and apheresis platelets

BACKGROUND: The GERMS Group initiated a prospective multicenter study to assess prevalence and nature of bacterial contamination of pooled buffy-coat platelet concentrates (PPCs) and apheresis platelet concentrates (APCs) by routine screening with a bacterial culture system. STUDY DESIGN AND METHODS: In nine centers overall, 52,243 platelet (PLT) concentrates (15,198 APCs, 37,045 PPCs) were analyzed by aerobic and anaerobic cultures (BacT/ALERT, bioMérieux). RESULTS: In 135 PLT concentrates (PCs; 0.26%), bacteria could be identified in the first culture (0.4% for APCs vs. 0.2% for PPCs; p < 0.001). In 37 (0.07%) of these PC units, the same bacteria strain could be identified in a second culture from the sample bag and/or the PC unit. The rate of confirmed-positive units did not differ significantly between APC (0.09%; 1/1169) and PPC units (0.06%; 1/1544). Bacteria from skin flora (Propionibacterium acnes, Staphylococcus epidermidis) were the most prevalent contaminants. Median times to first positive culture from start of incubation were 0.7 and 3.7 days in aerobic and anaerobic cultures for confirmed-positive units. With a "negative-to-date" issue strategy, most PC units (55%) had already been issued by time of the first positive culture. CONCLUSION: The rate of confirmed bacterial contamination of PC units was low. Nevertheless, clinicians must be aware of this risk. The risk of bacterial contamination does not warrant universal preference of APCs. It must be questioned whether routine bacterial screening by a culture method can sufficiently prevent contaminated products from being transfused due to the delay until a positive signal in the culture system and due to false-negative results.     

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.     

WBC content of platelet concentrates prepared by the buffy coat method using different processing procedures and storage solutions

BACKGROUND: The number of WBCs in platelet concentrates (PCs) prepared by the buffy coat (BC) method with different storage solutions can result in low (5 x 10(6)/unit) WBC levels by the use of careful centrifugation techniques without filtration. At present, most blood banks use filtration steps to meet these requirements. The difference in processing methods and suspension solutions prompted the investigation of the influence of the various procedures on the WBC and platelet content of PCs. STUDY DESIGN AND METHODS: PCs from 5 BCs were harvested without or with inline filtration (AutoStop BC, Pall Corp.) in either plasma (PCs-plasma) or platelet additive solution (PCs-PAS-2). After preparation, samples were taken for counting WBCs and platelets and for analyzing WBC subsets by flow cytometry using specific MoAbs. The WBCs were concentrated before analysis of the WBC subsets. Results less than 2.5 cells per microL were considered below the limit of accuracy of the subset analysis. RESULTS: All filtered PCs met the AABB standard of 5 x 10(6) per unit and the European guidelines of 1 x 10(6) per unit. None of the nonfiltered PCs met the European guidelines, but all met the AABB guidelines. All filtered units gave residual WBC counts below the detection limit for subset analysis. Filtered PCs-plasma gave significantly higher platelet counts than filtered PCs-PAS-2 or nonfiltered PCs (p<0.01, ANOVA). CONCLUSION: Careful centrifugation of pooled BCs, with plasma or PAS-2, can result in PCs with low WBC contamination levels. However, filtered PCs are superior, because of better WBC removal and higher platelet counts.     

Progressive platelet activation with storage: evidence for shortened survival of activated platelets after transfusion

Platelets are known to become activated during storage, but it is unclear whether such activation affects recovery or survival after platelet concentrate (PC) transfusion. With the use of flow cytometry to determine the percentage of platelets expressing the alpha-granule membrane protein 140 (GMP-140), a known adhesive ligand appearing on the platelet surface after activation, several studies were conducted. These investigations evaluated 1) the occurrence of significant platelet activation over time in PCs (n = 46) stored under standard blood bank conditions; 2) the correlation between platelet activation and platelet recovery in normal subjects after PC storage (n = 12), as assessed by the recovery of Indium-labeled platelets; and 3) the recovery of activated and unactivated platelets in thrombocytopenic cancer patients transfused with standard PCs (n = 11). It was determined 1) that an increasing duration of storage of PC was associated with increasing platelet activation as measured by the percentage of platelets expressing GMP-140, progressing from a mean of 4 +/- 2 percent (SD) on the day of collection to a mean of 25 +/- 8 percent by 5 days of storage: 2) that, in normal subjects, posttransfusion recovery of autologous platelets stored for 2 to 4 days and then labeled with In111 was inversely correlated with the percentage of activated platelets in the transfused PC (r = -0.55, p = 0.05); and 3) that, when thrombocytopenic patients were transfused with standard PCs, the recovery of the activated platelets in the transfused PCs averaged only 38 +/- 15 percent of the number predicted by the absolute platelet increment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fuji surge technique and continuous in-line filtration to improve the quality of single donor platelet concentrates

White blood cell (WBC)-reduced single donor platelet concentrates (SDPs) can be collected by most cell separators. WBC reduction can be achieved directly during plateletpheresis or by filtration. Continuous filtration with low filtration rates provides SDPs of good purity. To compensate the platelet (PLT) loss due to filtration, the PLT yield in the unfiltered primary product should be optimal. Fifty donors underwent plateletpheresis with the MCS+ blood cell separator (Haemonetics) with the new Fuji surge technique and continuous WBC filtration. Twelve SDPs were analysed for PLT yield, red blood cells (RBC), WBC, and pH after collection (Day 0) and at the end of storage (Day 5). Thereafter, further 38 SDPs were measured for PLT and WBC content in routine production at Day 0. PLT were determined electronically, RBC and WBC were counted manually (Neubauer and Nageotte chamber, respectively). For pH measurement, a pH-meter was used. Mean blood volume processed was 2621 +/- 112 ml in a donation time of 76 +/- 10 min. An average PLT yield of 3.45 +/- 0.88 x 10(11) was collected in a product volume of 325 +/- 77 ml. The collection efficiency was 60.0 +/- 5.5%. WBC contamination of all units tested was 0.046 +/- 0.059 x 10(6) and the RBC content of the SDPs analysed at Day 0 was 0.014 +/- 0.003 x 10(9). The pH was well maintained over the storage period of 5 days. The data indicate that Fuji surge technique and continuous in-line leukocyte filtration allow for the collection of SDPs with high platelet yield and low leukocyte contamination, meeting the Council of Europe quality standards.     

Properties of platelet concentrates prepared after extended whole blood holding time

Extension of the maximum holding time for whole blood collected into a CPD-ADSOL system from 6 to 8 hours at ambient temperature under conditions that cause the temperature of the blood to decrease to 20 to 24 degrees C would facilitate the preparation of platelet concentrates (PCs). In this study, the properties of CPD-PCs prepared and stored for 5 days in PL-732 containers after various initial holding periods were assessed in two laboratories, designated Laboratory A and Laboratory B. Laboratory A found higher platelet-rich plasma (PRP) volumes (276 +/- 25 vs. 249 +/- 19 mL) and platelet yields (76 +/- 18 vs. 66 +/- 18 x 10(9) platelets) with 8-hour holds (n = 10) than with 1- to 2-hour holds (n = 10), although only the difference in PRP volumes was significant (p less than 0.05). No significant difference was observed in autologous in vivo recovery (54 +/- 11 vs. 47 +/- 9%) or survival (167 +/- 37 vs. 170 +/- 25 hrs), as calculated by gamma function using 111In as radiolabel. Laboratory B also found higher PRP volumes (304 +/- 31 vs. 279 +/- 37 mL) and platelet yields with 8-hour holds (n = 12) than with a 6-hour holds (n = 10) (88 +/- 26 vs. 77 +/- 27 x 10(9) platelets). No significant differences were found in morphology score, the extent of release of beta-thromboglobulin, the discharge of lactate dehydrogenase, or hypotonic shock response.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of prestorage WBC reduction on the rates of febrile nonhemolytic transfusion reactions to platelet concentrates and RBC

BACKGROUND: Febrile non-hemolytic transfusion reactions (FNHTRs) are a common complication of platelet concentrate (PC) and RBC transfusions, usually ascribed to cytokines released by WBCs and perhaps the platelets themselves during storage. Prestorage WBC reduction should abrogate the accumulation of these cytokines reducing the number of FNHTRs. STUDY DESIGN AND METHODS: A retrospective analysis of FNHTR to PCs and RBCs before universal WBC reduction (PrUR) (July 1997-January 1998 for PCs, July 1997-July 1999 for RBCs) and after its introduction (PoUR) (February 1998-August 2001 for PC, August 1999-August 2001 for RBCs) was undertaken. All transfusion reactions were stratified based on component and date of reaction. Other adverse transfusion reactions were grouped into three periods: July 1997-January 1998, February 1998-July 1999, and August 1999-August 2001. A chi-square test was performed to determine the significance of the differences between groups. RESULTS: In the PRUR group, there were: 231 FNHTRs in 70,396 RBC units transfused (0.33%) and 29 FNHTRs in 6502 PC units transfused (0.45% percent). In the PoUR group, there were 136 FNHTRs in 72,949 RBC units transfused (0.19%, p < 0.001) and 56 FNHTRs in 50,555 PC units transfused (0.11%, p < 0.001). Of the other adverse events, only TRALI reactions were significantly reduced. CONCLUSION: Prestorage WBC reduction significantly reduced the rate of FNHTRs to PCs and RBCs.     

Results with new software for plateletpheresis systems

New software for the cell separators A 201 and CS 3000 Plus have been developed by Baxter. Fresenius recently offered a single needle option for the AS 104 device. The results of separation are described with respect to total platelet yield, efficiency and cell contamination of the platelet concentrate (PC). Two software programs were evaluated in both the A 201 (version 5.12 and 5.13) and AS 104 cell separators (version 4560 with different separation parameters according to protocol IV and V). With software version 5.12, the A 201 collected 2.0 +/- 0.9 x 10(11) platelets in 200 mL plasma whereas 2.3 +/- 0.7 x 10(11) platelets could be harvested with version 5.13. The separation efficiencies were 32.1 +/- 11.6 and 34.7 +/- 10.7%, respectively. The leucocyte contamination was 5.6 +/- 4.6 x 10(8) with software version 5.12 and 4.9 +/- 7.6 x 10(8) with the 5.13 version. With the CS 3000 Plus cell separator, 2.9 +/- 0.8 x 10(11) platelets (efficiency 38.4 +/- 8.2%) could be harvested in 208 +/- 2 mL plasma. The white blood cell contamination was extremely low (1.4 +/- 3.2 x 10(6). There was a high separation efficacy with the Fresenius single needle procedure of 59.1 +/- 10.6% (protocol IV) and 58.7 +/- 7.3% (protocol V), respectively. The total number of platelets sampled in 338 +/- 21 mL plasma was 3.1 +/- 0.8 x 10(11) in protocol IV.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevention of acquired defects in platelet function during blood processing

Two kinds of platelet concentrates were prepared in this study: one as pelleted platelets from platelet-rich plasma (PCs), and the other as a platelet suspension from the buffy coat fraction (nonpelleted PCs). The characteristics of both platelet concentrates were studied. White cell contamination in the nonpelleted PCs was below the threshold of detection by a microcell counter (less than 300 cells/microliter of concentrate); in the pelleted PCs, it was 3 +/- 1 x 10(7) cells per concentrate. The difference between the white cell contamination in pelleted PCs and nonpelleted PCs was significant (p less than 0.001). The degree of aggregation induced in pelleted PCs by ADP (9 microM) and collagen decreased to 33 and 55 percent, respectively, of that in platelet-rich plasma. The secondary wave of platelet aggregation induced by ADP and epinephrine was absent in pelleted PCs, and ATP secretion from these platelets by ADP stimulation also decreased remarkably. However, the degrees of aggregation and ATP secretion in nonpelleted PCs were similar to those in platelet-rich plasma. Furthermore, it was found that the amount of platelet factor 4 release seen in pelleted PCs was large in comparison to that in nonpelleted PCs and platelet-rich plasma. These results suggested that the deterioration of platelet function might have resulted from the platelet activation induced by pellet formation during the preparation of PCs from platelet-rich plasma.     

The flow rate significantly influences the leukocyte depletion rate during prestorage in-line filtration of platelet concentrates

BACKGROUND: White cell reduction of blood products minimizes the risks of alloimmunization against HLA-antigens, the transmission of viral diseases and the incidence of platelet transfusion reactions. One modern strategy is leukocyte depletion with an integrated filter system immediately after preparation and prior to storage. STUDY DESIGN AND METHODS: We evaluated the efficiency of a novel in-line filter system Sepacell PLX-5 BPS for leukocyte reduction of platelet concentrates (PC) from pooled buffy-coats. A total of 44 PCs were investigated with regard to different filtration flow rates (25-110 ml/min) and leukocyte depletion and thrombocyte recovery rates were analysed. Furthermore, we studied the influence of filtration on PCs over a storage period of 6 days (n = 12) by investigation of pH, lactate and glucose. Platelet function was determined by means of hypotonic shock response, external shape change and expression of CD62p. RESULTS: The mean leukocyte depletion rate was > log 5. After filtration the mean leukocyte count was 0.12 +/- 0.21 x 10(6). In 60% of the PCs the leukocyte count lay below the detection level of the Nageotte chamber, which is < 0.3 x 10(5). The flow rate correlates significantly with the leukocyte count in the PCs (r = 0.325; p = 0.033) and therefore with the leukocyte depletion rate (r = -0.422; p = 0.01). Flow rates under 40 ml lead to a significantly lower leukocyte contamination. Only in one PC, at a flow rate of 84 ml/min, was the leukocyte threshold of 1 x 10(6) exceeded. We did not find a significant correlation between filtration flow rate and thrombocyte recovery (r = 0.315; p = 0.069). The mean platelet count in the PC was 2.88 +/- 0.47 x 10(11). Compared with the thrombocyte count in the pooled buffy coat, the recovery was 68.6%. We observed a decrease of pH, glucose, external shape change and hypotonic shock response over the storage period while lactate and the expression of CD62p increased. CONCLUSION: The filter system Sepacell PLX-5 BPS proved to be suitable for in-line filtration of platelet concentrates prior to storage. Filtration flow rates of up to 40 ml/min allowed efficient leukocyte depletion without significant loss in the quality of the platelet concentrates and the platelet function in vitro.     

Transfusion-Transmitted Bacterial Infections - Haemovigilance Data of German Blood Establishments (1997-2010)

SUMMARY: METHODS: In order to evaluate the benefit of risk minimisation measures, reporting rates of transfusion-transmitted bacterial infections (TTBI) were calculated on the basis of annual reports and distributed blood components. Following the implementation of risk minimisation measures in 2003 and 2008, a comparison of pre- and post-implementation periods was performed. RESULTS: During a period of 14 years, 90 cases of TTBI were confirmed, 34 were caused by red blood cell (RBC) concentrates, 5 by fresh frozen plasma, and 51 by platelet concentrates (PCs). The overall reporting frequency was 1 TTBI in 1.91 million RBC units; 1 TTBI in 0.094 million PC units, and 1 TTBI-associated fatality in 0.57 million PC units. From 2001-2004 the reporting rate was 13.7 per million PC units; 2005-2008, after the implementation of pre-donation sampling; it was 10.8 per million PC units (p > 0.5). After limitation of the shelf life (2008), the reporting rate decreased to 4.49 per million PC units (p = 0.12), and one case of related fatality was reported. Agents with low pathogenicity were reported in 14 of 41 immunosuppressed patients (34%) but only in 1 of 13 patients with non-haematological/oncological diseases. CONCLUSION: TTBI and associated fatalities could be gradually reduced by the risk minimisation measures, but further strategies such as implementation of sensitive screening tests or pathogen-reducing approaches should be discussed.     

The effect of storage on the expression of platelet membrane phosphatidylserine and the subsequent impacton the coagulant function of stored platelets

BACKGROUND: Platelet concentrates (PCs) derived from whole blood and stored under standard blood bank conditions undergo changes that are referred to as the platelet storage lesion. This study assesses the effect of PC preparation and storage on the distribution of phosphatidylserine (PS) in the platelet membrane and the effect that this distribution may have on the thrombogenic potential of stored PCs. STUDY DESIGN AND METHODS: Fresh platelets and PCs donated by healthy donors were obtained. PCs derived from platelet-rich plasma were studied on Day 1, Day 3, and Day 6 of storage under blood bank conditions. RESULTS: Platelet aggregation after exposure to the platelet agonists ADP and epinephrine singly declined progressively, but, when ADP and epinephrine in combination and collagen and thrombin in combination were used as agonists, the decline in platelet aggregation was less marked. PS expression as measured by Annexin V binding (mean and SD) was 2.02 +/- 0.93 percent in fresh platelet samples and increased to 5.39 +/- 4.2 percent on Day 1, 22. 1 +/- 7.1 percent on Day 3, and 39.5 +/- 12.1 percent on Day 6. Platelet prothrombinase activity (mean +/- SD) as measured by thrombin generation increased from 1.49 +/- 0.7 micro per mL in fresh platelet samples to 3.68 +/- 1.1 micro per mL in Day 1 platelets (p<0.001), 5.15 +/- 2.5 micro per mL in Day 3 platelets (p<0.001), and 4.65 +/- 2.48 micro per mL in Day 6 platelets (p<0. 001). CONCLUSION: These results show that PS expression increases after preparation of PCs from platelet-rich plasma and rises progressively during platelet storage under blood bank conditions. Furthermore, the greater PS expression is associated with increased platelet- dependent thrombin-generating capacity.