A multicenter evaluation of the routine use of a new white cell-reduction apheresis system for collection of platelets

Platelet Transfusion for Patients With Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update

Purpose

To provide evidence-based guidance on the use of platelet transfusion in people with cancer. This guideline updates and replaces the previous ASCO platelet transfusion guideline published initially in 2001.

Methods

ASCO convened an Expert Panel and conducted a systematic review of the medical literature published from September 1, 2014, through October 26, 2016. This review builds on two 2015 systematic reviews that were conducted by the AABB and the International Collaboration for Transfusion Medicine Guidelines. For clinical questions that were not addressed by the AABB and the International Collaboration for Transfusion Medicine Guidelines (the use of leukoreduction and platelet transfusion in solid tumors or chronic, stable severe thrombocytopenia) or that were addressed partially (invasive procedures), the ASCO search extended back to January 2000.

Results

The updated ASCO review included 24 more recent publications: three clinical practice guidelines, eight systematic reviews, and 13 observational studies.

Recommendations

The most substantial change to a previous recommendation involved platelet transfusion in the setting of hematopoietic stem-cell transplantation. Based on data from randomized controlled trials, adult patients who undergo autologous stem-cell transplantation at experienced centers may receive a platelet transfusion at the first sign of bleeding, rather than prophylactically. Prophylactic platelet transfusion at defined platelet count thresholds is still recommended for pediatric patients undergoing autologous stem-cell transplantation and for adult and pediatric patients undergoing allogeneic stem-cell transplantation. Other recommendations address platelet transfusion in patients with hematologic malignancies or solid tumors or in those who undergo invasive procedures. Guidance is also provided regarding the production of platelet products, prevention of Rh alloimmunization, and management of refractoriness to platelet transfusion ( www.asco.org/supportive-care-guidelines and www.asco.org/guidelineswiki ).

Evaluation of a new apheresis system for the collection of leukoreduced single-donor platelets

BACKGROUND

The Fresenius COM.TEC cell separator is a new device for producing white cell concentrates (WBCs) and leukoreduced single-donor platelet concentrates (SDPs) and performing therapeutic cytapheresis and plasmapheresis that might replace the Fresenius systems AS104 and AS.TEC 204. This novel system's performance was evaluated for producing leukoreduced SDPs.

STUDY DESIGN AND METHODS

In an investigational phase, each of 200 donors underwent plateletpheresis with the AS.TEC 204 and the COM.TEC systems. The collection efficiency (CE) and WBC contamination of the different techniques were compared. After some hard- and software modifications, the system was evaluated in an additional 800 procedures in the confirmatory phase.

RESULTS

In the investigational phase, the CE of the COM.TEC device was increased significantly in comparison to the AS.TEC 204 device's CE (by 45 +/- 32% when collecting 1 unit of platelets [PLTs] and 1 unit of fresh-frozen plasma and by 43 +/- 42% when collecting only 1 unit of PLTs). Although all AS.TEC products proved to be leukoreduced, 2 percent of the COM.TEC procedures led to PLT concentrates containing more than 1 x 10(6) WBCs. In the confirmatory phase, all 1300 products from 800 COM.TEC procedures proved to be leukoreduced. Furthermore, the CE increased significantly from 53.5 +/- 4.6 percent in the investigational phase to 55.5 +/- 4.9 percent (p < 0.001) in the confirmatory phase.

CONCLUSIONS

These data suggest that the new COM.TEC system offers a significantly and importantly improved CE in plateletpheresis procedures in comparison to the AS.TEC system. In the final version, the PLT products collected with this system fulfill the most stringent criteria for leukoreduced PLTs. This aim was achieved without additional filtration steps and thus without filtration-related PLT loss.

Platelet transfusions

Ever since platelet transfusions were shown to reduce mortality from haemorrhage in patients with acute leukaemia in the 1950s, the use of this therapy has steadily grown to become an essential part of the treatment of cancer, haematological malignancies, marrow failure, and haematopoietic stem cell transplantation. Today, more than 1.5 million platelet products are transfused in the USA each year, 2.9 million products in Europe. However, platelet transfusion can transmit infections and trigger serious immune reactions and they can be rendered ineffective by alloimmunisation. There are several types of platelet components and all can be modified to reduce the chances of many of the complications of platelet transfusion. Transfusion practices, including indications for transfusion, dose of platelets transfused, and methods of treating alloimmunised recipients vary between countries, and even within countries. We review commonly used platelet components, product modifications, transfusion practices, and adverse consequences of platelet transfusions.

Prospective comparison of high-dose plateletpheresis with the latest apheresis systems on the same donors

BACKGROUND

To improve productivity of automated platelet (PLT) collection, the industry has introduced new instruments or modifications to existing equipment.

STUDY DESIGN AND METHODS

With the same 8 donors for double (DDC) and triple-dose PLT collection (TDC), the Baxter Amicus (AM), the Haemonetics MCS Plus (MCS+), and the Gambro Trima Accel (TA) were evaluated focusing on yield, duration, and citrate donor load. Target endpoints were set at 5.5 x 10(11) to 6.0 x 10(11) PLTs (DDC) and 7.5 x 10(11) to 8.0 x 10(11) PLTs (TDC) in up to 100 and 120 minutes' donation time, respectively.

RESULTS

TA was the most efficient system (74.5 +/- 3.9%) with significant differences from AM (71.1 +/- 3.9%; p = 0.028) and MCS+ (64.0 +/- 7.7%; p = 0.002). TA had advantages over AM for collection rate (10.9 x 10(9) +/- 2.2 x 10(9) vs. 10.1 x 10(9) +/- 1.5 x 10(9) PLTs/min; p = 0.382), whole blood processed (3928 +/- 611 mL vs. 4219 +/- 727 mL; p = 0.382), and time to obtain an established standard dose (TSD 2.5(EU), 30.2 +/- 5.6 vs. 37.7 +/- 5.5 min; TSD 3.5(US), 42.2 +/- 7.8 min vs. 52.7 +/- 7.7 min; p = 0.015), whereas AM was slightly superior in PLT yield (2.81 x 10(11) +/- 0.21 x 10(11) vs. 2.76 x 10(11) +/- 0.31 x 10(11)/unit; p = 0.645). Owing to the lowest draw (42.3 +/- 3.2 mL/min; p < 0.001) and collection rates (6.0 x 10(11) +/- 1.5 x 10(11)/min; p = 0.021), MCS+ was the slowest significantly (p < 0.001) but compensated with fewer citrate reactions owing to lower citrate infusion rates (0.78 +/- 0.11 mL/min/L; p = 0.028).

CONCLUSION

High-dose plateletpheresis was performed efficiently and safely with all three instruments. AM had advantages in PLT yield, and MCS+, in donor comfort. TA was the fastest in obtaining an established standard dose and, because of this advantage, the machine with the highest practical impact in routine use.

Evaluation of concurrent collection of in-line filtered platelets and packed red blood cells by multicomponent apheresis with three last-generation apparatuses

BACKGROUND AND OBJECTIVES

Multicomponent apheresis enables the collection and procession of different blood products in a single donation. Different apparatuses vary in terms of principle and efficiency. Knowledge of them is essential to analyse cost effectiveness.

MATERIALS AND METHODS

A total of 30 donors, well matched for baseline parameters, were randomly assigned to the concurrent collection of red blood cells (RBCs) and platelets (PLTs) with the Baxter Amicus (AM), the Haemonetics MCS plus (MCS+), and the Gambro Trima Accel (TA). The procedures were prospectively evaluated, focusing on yield, time, efficiency, citrate donor load and in vitro quality.

RESULTS

PLT yield (x 10(11)/unit; mean +/- standard deviation) was 3.09 +/- 0.34 (AM), 2.53 +/- 0.35 (MCS+), 2.51 +/- 0.32 (TA). Absolute RBC mass (ml/unit; mean +/- standard deviation) was 177.4 +/- 2.7 (AM), 161.5 +/- 0.7 (MCS+), and 163.7 +/- 5.4 (TA). The programmed RBC collection target of 160-180 ml was reached by all instruments, whereas the programmed PLT yield of 3.0 x 10(11) was met satisfactorily by AM only. All units contained < 1 x 10(6) WBCs. In vitro RBC quality was equivalent among the systems. No significant differences were noted with collection efficiency, processed whole blood or citrate donor load. Owing to high collection and draw rates, the TA was the fastest of all the systems. The MCS+ had the longest donation/needle time and the highest PLT activation, but compensated with significantly lower draw and citrate infusion rates. The overall processing time was longest with the AM, as a result of manual procedures from donor disconnection to the final products.

CONCLUSIONS

Multicomponent apheresis was performed safely and efficiently with all three instruments. There was no 'magic apparatus' as each system combined advantages and pitfalls for the diverse parameters evaluated.

A flow cytometric method for detection and enumeration of low-level, residual red blood cells in platelets and mononuclear cell products

BACKGROUND

Conventional automated cell counters cannot accurately count residual red blood cells (rRBCs) that are often present in various blood products. A two-color flow cytometric method (FC) was validated for detecting and enumerating rRBCs in platelets (PLTs) and mononuclear cell (MNC) products.

STUDY DESIGN AND METHODS

PLT and MNC products for PLTs (CD61-fluorescein isothiocyanate) and rRBC (anti-glycophorin A-phycoerythrin) were double stained, and data were acquired with a flow cytometer. Assay linearity, accuracy, and precision were assessed with a standard-dilution series of rRBCs. This assay was used to determine the rRBCs of apheresis PLTs collected with Trima Accel (Gambro BCT) and MNC products collected with the COBE Spectra (Gambro BCT).

RESULTS

The linear range of this assay in PLT and MNC products is 10 to 2000 RBCs per microL (R2=0.994). FC had a mean intraassay coefficient of variation of 11.8 percent at 34 RBCs per microL. A standard clinical hematology analyzer overestimated rRBCs in MNC products by 1.59x10(5)+/-0.7x10(5) RBCs per microL. Apheresis PLTs had a median of 17.4 RBCs per microL, with 99.0 percent containing fewer than 90.0 RBCs per microL.

CONCLUSIONS

This method for determining rRBCs in blood products is accurate and repeatable with a lower limit of detection adequate to assess currently available blood products. FC should be considered for determining rRBCs in MNC products.

A randomized crossover trial comparing three plateletpheresis machines

BACKGROUND

The aim of the study was to compare three different apheresis machines with the same donors regarding the processing time required to obtain a 3.5 x 10(11) platelet (PLT) dose and acceptance by donors.

STUDY DESIGN AND METHODS

A randomized crossover trial was performed to evaluate the differences between the Amicus Crescendo (Baxter Biotech Corp.), the MCS Plus (Haemonetics Corp.), and the Trima Accel (Gambro BCT). Donations from 51 donors were compared for time adjusted to obtain a standard 3.5 x 10(11) PLT dose (TSD3.5), efficiency, adverse reactions, yield, leukodepletion, machine accuracy, and donor preferences. Processing times were measured by chronometer. The same vein access was used during all three processes in each donor. In the statistical analysis, to take into account the nonindependence of several measurements from the same donor, generalized estimating equations were used with an autoregressive correlation matrix.

RESULTS

The Accel produced a TSD3.5 (mean +/- SEM) of 47.9 +/- 1.0 min; the Amicus, 60.3 +/- 1.0 min; and the MCS Plus, 66.7 +/- 1.0 (p < 0.0001). The Amicus presented the greatest efficiency (87.5%; p < 0.0028). The MCS Plus demonstrated the highest capacity for leukodepletion (p < 0.0002) despite one process presenting more than 1 x 10(6) white blood cells per unit. The MCS Plus also measured the processing time with the greatest accuracy. No severe adverse effects were observed. The donors preferred the Accel (61%) followed by the Amicus (35%) and the MCS Plus (4%; p < 0.0001) and the processing speed was the most highly valued measure (55%).

CONCLUSIONS

The Accel is the fastest and, because of this advantage, the machine preferred by donors. The Amicus was the most efficient and the MCS Plus was the only one not to underestimate the processing time.

Paired comparison of Gambro Trima Accel versus Baxter Amicus single-needle plateletpheresis

BACKGROUND

Gambro BCT recently introduced the Trima Accel Version 5 (TR) plateletpheresis machine. Platelet (PLT) yields, collection efficiencies (CEs), numbers of white blood cells (WBCs), and processing times of the TR versus the Amicus (Version 2.51) single-needle (AM) procedures were evaluated by use of a prospective paired comparison.

STUDY DESIGN AND METHODS

Target yields of 3.0 x 10(11) to 6.8 x 10(11) PLTs in up to 100 minutes of processing time were used. To detect a difference of 1.0 x 10(11) PLTs with a power of 80 percent, 26 paired comparisons were needed.

RESULTS

The mean amount of whole blood processed was significantly higher for TR than for AM (3795 vs. 3520 mL). The TR and AM were equivalent in regard to mean preprocedure PLT count (259 x 10(9) vs. 251 x 10(9)/L), PLT yields (6.7 x 10(11) vs. 6.5 x 10(11)), split rate (65% vs. 65%), processing time (73 vs. 78 min), and collection rate (0.090 x 10(11) vs. 0.084 x 10(11) PLTs/min). The TR had a significantly lower CE than the AM (76% vs. 86%). All of the products (after splitting) had fewer than 5 x 10(6) WBCs.

CONCLUSIONS

The Trima Accel machine processed significantly more whole blood with equivalent PLT yields, processing time, and number of PLTs per minute compared to the Amicus single-needle procedure, but had a significantly lower CE.

First comparison of productivity and citrate donor load between the Trima version 4 (dual-stage filler) and the Trima Accel (single-stage filler) in the same donors

BACKGROUND AND OBJECTIVES

Aside from new software the blood cell separator TRIMA (GambroBCT) also received a newly designed separation chamber offering a novel single stage separation technology, called Trima Accel. We evaluated this new system focusing on productivity and donor comfort by comparing it to the previous version (Trima version 4) in collecting single-donor platelet concentrates (SD-PCs) and plasma.

MATERIALS AND METHODS

Each of 20 donors underwent platelet apheresis using both devices. We compared the collection efficiency (CE), the collections rate (CR), the volume of the collected plasma and the residual leukocytes. Furthermore we compared donor comfort in terms of duration of the donation, flow of citrate back to the donor and platelet and white blood cell (WBC) loss.

RESULTS

While the number of collected platelets and the platelet concentration did not differ significantly between both techniques the time of the procedure was reduced by 15.6% with Trima Accel. This results in an increase of the CR and CE of 25% and 15% respectively when using Trima Accel. Log normal probability plotting of WBC counts showed that both techniques complied with the European and the US leukoreduction guidelines. The mean flow of ACDA to the donor per minute and per litre blood volume was also reduced by 20%.

CONCLUSION

These data show that the Trima Accel represents a further improvement in apheresis platelet production with a better productivity and donor comfort, especially regarding the mean flow of ACDA to the donor.

A comparison of PLT collections from two apheresis devices

BACKGROUND

The aim of this study was to compare two apheresis devices (COBE Trima and COBE Spectra, Gambro BCT).

STUDY DESIGN AND METHODS

The study compares 103 Trima procedures with 61 Spectra procedures. The comparison of single-donor PLTs (SDPs) separation parameters and anticoagulant infusion to the donors were the primary targets. Yield and residual amounts of WBCs of SDPs were secondary targets. Residual amounts of WBCs were measured with the Nageotte method.

RESULTS

Trima and Spectra groups were comparable before apheresis. Two procedures were terminated before completion in the Trima group owing to vein damage. Trima infused more anticoagulant--352 +/- 104 mL versus 297 +/- 75 mL (p < 0.01)--and was quicker than Spectra. The time to obtain 3.5 x 10(11) was (median) 55.8 minutes for the Trima machine and 80.3 minutes for Spectra machine (p < 0.001). Regarding leukoreduction, all the SDPs had fewer than 1 x 10(6) WBCs per unit except for one in product obtained by the Trima machine.

CONCLUSIONS

The Trima machine is faster and more efficient than the Spectra machine, and both machines allow standard leukoreduced SDPs to be obtained. Although donors receive a higher anticoagulant infusion with the Trima machine, their tolerance is acceptable.

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.

Collection of WBC-reduced single-donor PLT concentrates with a new blood cell separator: results of a multicenter study

BACKGROUND

A new cell separator (COM.TEC, Fresenius) was recently developed aimed at efficient collection of WBC-reduced single-donor PLT concentrates (SDPs).

STUDY DESIGN AND METHODS

Five German centers collected 554 WBC-reduced SDPs with help of the COM.TEC cell separator. Two multicenter cell counting studies were performed at the beginning and at the end of the study to document uniform counting results among the participating centers.

RESULTS

A total of 441 (79.6%) PLT collections were included in the study according to the protocol. A total of 342 single-dose and 99 double-dose SDPs were collected. For single-dose SDPs, an average blood volume of 2826 +/- 409 mL was processed in a donation time of 55 +/- 11 minutes. Mean PLT yield of these products was 3.11 x 1011+/- 0.40 x 1011 and the WBC contamination was 0.11 x 106+/- 0.20 x 106. For double-dose SDPs (PLT count, 5.29 +/- 0.93 x 1011), 3943 +/- 639 mL was processed. The average difference between the target and the collected PLT concentration was -2.8 +/- 12.0 percent for single-dose SDPs and -1.8 +/- 9.5 for double-dose SDPs, respectively. The collection efficiency was 53.7 +/- 5.8 percent for single-dose SDPs and 58.2 +/- 6.2 percent for double-dose SDPs. If all results of each sample from the counting study were set to unity (to the mean over all centers), most PLT determinations were very similar to the mean, for example, near or 1 if set to unity.

CONCLUSION

The COM.TEC machine makes it possible to obtain WBC-reduced SDPs that comply with current standards.

Cytokine levels as performance indicators for white blood cell reduction of platelet concentrates

BACKGROUND AND OBJECTIVES

With the implementation of universal white blood cell (WBC) reduction in the UK, in-process WBC-reduction filters for pooled buffy coat (BC)-derived platelet concentrates (PCs) and apheresis methods are used routinely for the production of WBC-reduced PCs. While these strategies meet the specification for WBC reduction (< 5 x 10(6) WBCs/unit), the products from these processes may differ depending on the process employed and its performance. The aim of this study was therefore to investigate whether PCs prepared using various WBC-reduction processes are sufficiently depleted of WBCs to limit cytokine accumulation during storage and to assess if cytokine levels detected in platelet products can serve as indicators of acceptable platelet activation as a result of the WBC-reduction process.

MATERIALS AND METHODS

We measured the levels of cytokines predominantly derived from WBCs [e.g. interleukin-8 (IL-8)] and platelets [e.g. regulated on activation, normal, T-cell expressed, and secreted (RANTES) and transforming growth factor-beta(1) (TGF-beta(1))] under the present experimental conditions in different WBC-reduced PCs, i.e. PCs prepared from three different WBC-reduction filters and control non-filtered PCs using pooled BCs from the same donors and three apheresis types. Supernatant plasma was collected at the beginning (day 1) and end (day 5) of the shelf life of each PC, and the cytokine content was determined using appropriate enzyme-linked immunosorbent assays (ELISAs). Process efficiency was assessed by platelet yield and residual WBC count.

RESULTS

We found that products from the apheresis process involving a filtration step (Haemonetics MCS+) showed a lower cytokine content on both day 1 and day 5 in comparison with the fluidized bed (COBE Spectra) or elutriation (Amicus) processes. WBC reduction of BC-PCs of the same origin using three different filters showed comparable levels of cytokines on day 1 in all units. After storage for 5 days, the levels of IL-8 remained essentially unchanged in filtered BC-PCs but increased by more than threefold in control non-filtered BC-PCs, suggesting IL-8 release by residual WBCs present in the control PCs. The concentration of platelet-derived cytokines such as RANTES and TGF-beta(1), however, increased significantly in all filtered and control non-filtered PCs during the storage period.

CONCLUSION

These results show that markers of cytokine release from both WBCs and platelets are useful indicators of the performance and efficacy of the WBC-reduction process and of platelet quality.

Absence of D alloimmunization in D- pediatric oncology patients receiving D-incompatible single-donor platelets

BACKGROUND

Guidelines are lacking for prophylaxis against D alloimmunization after D-incompatible platelet transfusion. A rational basis for the application of prophylaxis would be beneficial for institutions in which inventory constraints demand the administration of large numbers of D-incompatible platelets.

STUDY DESIGN AND METHODS

A retrospective analysis was performed of all D-incompatible platelet transfusions administered at a pediatric research hospital over a 1.5-year period. Patients exclusively received single-donor WBC-reduced platelets and did not receive RhIg immunoprophylaxis. Numbers, source, ABO type, duration of serologic follow-up, and level of RBC contamination of D-incompatible transfusions were analyzed. All positive D serologies in the institution over a 3.5-year period were examined to determine cause and potential association with platelet transfusion.

RESULTS

Thirty-five patients not receiving bone marrow transplant and seven bone marrow transplant patients received 490 and 255 D-incompatible transfusions, respectively, over 1.5 years. Patients had various diagnoses, predominantly malignancies. Seventy-nine percent of D-incompatible transfusions were ABO compatible. An estimated 2300 incompatible transfusions were performed over 3.5 years. No case of D alloimmunization was detected.

CONCLUSIONS

D immunoprophylaxis is generally unnecessary in pediatric oncology patients receiving D-incompatible, WBC-reduced, single-donor platelets not visibly contaminated by RBCs. Further studies to validate these observations in the pediatric population and to extend them to other population groups are warranted.

Preparation of FFP as a by-product of plateletpheresis

BACKGROUND

To reduce the production costs of single-donor platelets (SDPs), a study was conducted to investigate whether plasma collected as a by-product of plateletpheresis satisfies the quality requirements for FFP without impairing the quality of the SDP component.

STUDY DESIGN AND METHODS

Ninety-two donors with platelet (PLT) counts <270 x 10(9) per L underwent plateletpheresis using an automated cell separator (Spectra Apheresis System with the Leukoreduction System [LRS], Gambro BCT, Lakewood, CO). The machine was programmed to collect 3 x 10(11) PLTs in 250 mL of plasma with an additional unit of 350 mL of plasma or 3 x 10(11) PLTs in 250 mL of plasma without additional plasma in 10 procedures. FV and FVIII and residual RBCs, WBCs, and PLTs in the plasma were measured for quality control.

RESULTS

FV was 0.87 +/- 0.18 IU per mL, and FVIII was 1.32 +/- 0.48 IU per mL in the plasma components (n = 41). The recovery was 94.1 +/- 5.5 percent for FV and 102.2 +/- 9.5 percent for FVIII when compared with the donors' predonation values. Residual cells were 0.002 +/- 0.009 x 10(9) RBCs per L (n = 30), 12 +/- 6 x 10(9) PLTs per L (n = 30), and 0.32 +/- 0.37 x 10(6) WBCs per L (n = 92).

CONCLUSIONS

Using the automated cell separator and special software, it is possible to collect plasma as a by-product of plateletpheresis that meets the properties requested for FFP without impairing the quality of the SDP components. The content of clotting factors is within the requested range for FFP. Residual cell counts are within all European and U.S. specifications for FFP, and the WBC content even satisfies the criteria for WBC-reduced blood components. The collection of FFP as a by-product does not cause any additional costs and thus helps to reduce the costs in preparing blood components.

Different preparation methods to obtain platelet components as a source of growth factors for local application

BACKGROUND

Autologous platelet components were recently used as part of tissue-engineering strategies in oral and maxillofacial surgery. Various preparation methods were investigated to define standardized blood bank components and to collect data on the growth factor content of human platelets before and after storage.

STUDY DESIGN AND METHODS

Apheresis platelets (AP), buffy coat-derived platelets (BCP), platelets prepared by tube method (TP), and highly concentrated samples prepared from AP and from BCP were evaluated for standard quality criteria of platelet components and for their concentration of transforming growth factor (TGF)-ss1, platelet-derived growth factor (PDGF)-AB, and PDGF-BB. AP were stored for 5 days. On Days 3 and 5, these components and freshly prepared, highly concentrated samples were evaluated for the same measures.

RESULTS

Platelet concentration in TP was lower than that in the other groups (p<0.05). However, the concentrations of PDGF-AB, PDGF-BB, and TGF-ss1 were comparable in the three groups. TP showed higher spontaneous CD62 expression than did AP and BCP. The three preparation procedures resulted in significantly different WBC contamination, with the highest levels in TP. For the whole series of measurements, there was a strong correlation between growth factor levels and platelet concentration (p<0.05), which was due to the face that the growth factor content of concentrated platelet samples was tenfold that of AP, BCP, and TP. In TP, the WBC concentration was correlated with PDGF levels (p<0.05). After 5-day storage, the mean levels of PDGF-AB, PDGF-BB, and TGF-ss1 were 57.1, 43.0, and 72.0 percent of the initial values in AP. Overall, multiple regression analysis revealed the following factors influencing the measured growth factor concentrations: platelet concentration, baseline CD62 expression, lactate production, and WBC contamination.

CONCLUSION

Various methods enable the preparation of platelet components and of highly concentrated components for local use according to standard blood banking criteria. The obtained components differ, particularly in their WBC content and in vitro platelet activation. These findings are relevant for planning and evaluating further studies of locally usable autologous platelet components.

Extracellular accumulation of bioactive substances during preparation and storage of various platelet concentrates

BACKGROUND

Side effects of platelet transfusion may be associated with infusion of bioactive substances. We therefore studied extracellular accumulation of histamine, plasminogen activator inhibitor (PAI)-1, vascular endothelial growth factor (VEGF), and interleukin (IL)-6 during preparation and storage of various platelet concentrates.

METHODS

Twenty buffy-coat-derived platelet pools (BCPC) were prepared and stored in platelet additive solutions (PAS). Twelve apheresis platelet (APC) units were prepared using the COBE Spectra LRS, and 14 were prepared using the Fenwal Amicus Separator. After preparation half of the content was drawn from each APC unit. The normal ranges of the substances were determined in plasma from all donors, and the extracellular concentrations of the substances were determined in supernatants collected on days 0, 1, 3, 5, and 7 of storage from all platelet preparations.

RESULTS

The platelet counts were not significantly different in BCPC units and APC units. The BCPC units had a significantly higher white cell count than the APC units (P < 0.0001), but the count was significantly higher in the Amicus APC units than in the COBE APC units (P < 0.0001). The extracellular histamine concentration was significantly (P < 0.001) increased in BCPC units after preparation and without further increase during storage, while there was no accumulation of histamine in APC units. After preparation the PAI-1 concentration was significantly (P < 0.02) higher in BCPC units than in APC units, but during storage PAI-1 increased significantly (P < 0.05) more in APC units than in BCPC units. Similarly, VEGF concentration was significantly (P < 0.05) higher in BCPC units than in APC units after preparation. During storage, however, VEGF increased more in BCPC units compared with COBE Spectra APC units (P < 0.05), but compared with Amicus Separator APC units only for the first 3 days of storage. At days 5 and 7 of storage the VEGF concentration was significantly higher in the Amicus APC units than in the COBE APC units (P < 0.05). IL-6 was not detectable in any of the concentrates after preparation or during storage.

CONCLUSION

Platelet concentrates prepared by the apheresis method may contain less white cell derived bioactive substances than platelet concentrates prepared by the buffy-coat method. However, a substantial storage time dependent platelet derived bioactive substance accumulation takes place in all platelet concentrates tested, presumably due to platelet disintegration.

The effect of leukocyte-reduction method on the amount of human cytomegalovirus in blood products: a comparison of apheresis and filtration methods

This study examined the effectiveness of 3 leukocyte-reduction (LR) methods in depleting the residual level of cytomegalovirus (CMV) in blood products measured by quantitative polymerase chain reaction (QA-PCR). At 2 locations over 3 allergy seasons, apheresis platelets and whole blood were collected from 52 healthy CMV seropositive subjects having an elevated titer of CMV DNA (median = 2400 genome equivalents [GE]/mL) resulting in 32 evaluable LR apheresis platelets, 31 filtered platelets from whole blood, and 31 filtered red blood cells (RBCs) from whole blood. Leukoreduction by apheresis and filtration resulted in substantial reduction of detectable CMV DNA levels with 99.9% of the LR products expected to have less than 500 GE/mL of CMV DNA. No difference was found between methods (P = .52). CMV genomic leukocyte subset localization was determined by QA-PCR of fluorescence-activated cell sorter (FACS)-sorted peripheral blood from 20 seropositive subjects (n = 10 &gt; 100 GE/mL, n = 10 QA-PCR negative). CMV was detected in monocyte (13 of 20) and granulocyte (3 of 20) fractions. Presence of competent virus in QA-PCR positive (&gt; 100 GE/mL) peripheral blood samples was verified with 4 of 19 subjects positive in shell vial assay, and 8 of 18 positive for CMV gene products (messenger RNA). We observed a seasonal DNAemia variation in seropositive subjects. CMV seropositive subjects (n = 45) entered into longitudinal monitoring in March/April 1999 were QA-PCR negative at baseline. Subjects converted to a positive QA-PCR coincident with increased seasonal allergen levels (Norfolk 15 of 18 evaluable in 43.4 ± 9.48 days; Denver, 16 of 23 evaluable in 96 ± 26.3 days). These data demonstrate effective reduction of CMV load by LR during periods of DNAemia in CMV seropositive subjects.

Platelet transfusion for patients with cancer: clinical practice guidelines of the American Society of Clinical Oncology

OBJECTIVE

To determine the most effective, evidence-based approach to the use of platelet transfusions in patients with cancer.

OUTCOMES

Outcomes of interest included prevention of morbidity and mortality from hemorrhage, effects on survival, quality of life, toxicity reduction, and cost-effectiveness.

EVIDENCE

A complete MedLine search was performed of the past 20 years of the medical literature. Keywords included platelet transfusion, alloimmunization, hemorrhage, threshold and thrombocytopenia. The search was broadened by articles from the bibliographies of selected articles.

VALUES

Levels of evidence and guideline grades were rated by a standard process. More weight was given to studies that tested a hypothesis directly related to one of the primary outcomes in a randomized design. BENEFITS/HARMS/COST: The possible consequences of different approaches to the use of platelet transfusion were considered in evaluating a preference for one or another technique producing similar outcomes. Cost alone was not a determining factor.

RECOMMENDATIONS

Appendix A summarizes the recommendations concerning the choice of particular platelet preparations, the use of prophylactic platelet transfusions, indications for transfusion in selected clinical situations, and the diagnosis, prevention, and management of refractoriness to platelet transfusion.

VALIDATION

Five outside reviewers, the ASCO Health Services Research Committee, and the ASCO Board reviewed this document.

SPONSOR

American Society of Clinical Oncology

Comparison of a new WBC-reduction system and the standard plateletpheresis protocol in the same donors

BACKGROUND

A cell separator (Spectra, Gambro BCT) with an integrated leukoreduction system (LRS) for producing WBC-reduced single-donor platelet concentrates has been shown to result in a slightly reduced collection efficiency as compared to the former Spectra system without LRS. A novel modified system for improved collection efficiencies (LRS Turbo, Gambro BCT) was evaluated.

STUDY DESIGN AND METHODS

Each of 37 donors underwent plateletpheresis using the LRS Turbo (LRS-T) and the standard LRS (LRS) of the Spectra cell separator. The collection efficiency and WBC contamination of the different techniques were compared. Platelets were counted automatically and WBCs were counted by using one or two full grids of a Nageotte chamber.

RESULTS

The preseparation and postseparation numbers of RBCs, WBCs, and platelets, as well as the number of collected platelets, did not differ for the two techniques. In the LRS-T separations, the collection efficiency was 112 percent of that in the LRS procedures. Median residual WBCs in the platelet components were 0.0256 x 10(6) per LRS-T procedure and 0.0253 x 10(6) per LRS procedure. The purity of the LRS-T components was not less than that of the standard LRS components, whereas the collection efficiency of the LRS-T was significantly greater, 44.9 percent versus 40.7 percent.

CONCLUSIONS

The LRS-T procedures produced platelet concentrates with WBC-reduction capacity that is comparable to that obtained with the standard LRS procedures, which have previously been described as satisfying the most stringent criteria for WBC-reduced platelets. The new technique significantly improved the collection efficiency of the plateletpheresis procedure.

Effect of gamma radiation on the in vitro aggregability of WBC-reduced apheresis platelets

BACKGROUND

The effect of gamma radiation on single-donor apheresis platelet concentrates (SDPs) has been elucidated only incompletely. The only existing report on the function of SDPs stored in the irradiated state found a deterioration in the in vitro aggregability at the end of shelf life in SDPs divided before irradiation with 1500 cGy.

STUDY DESIGN AND METHODS

The in vitro properties of platelets were examined in four series of irradiated and control platelets, each obtained from the same 15 donors. Irradiation with 3000 cGy was performed on Days 0, 3, and 5. Cellular content, aggregability by ADP alone or ADP and epinephrine, spontaneous and induced CD62 expression, beta-thromboglobulin release, glucose consumption, lactate production, and pH were measured immediately after preparation and on Days 3 and 5 after donation.

RESULTS

Comparable in vitro properties were measured in irradiated and control platelets, whether irradiation was performed on Day 3 or Day 5. However, in platelets irradiated on Day 0, we found a significantly better in vitro aggregability by 20 microM: ADP immediately after irradiation and by 10 microM: ADP and 2 microM: epinephrine at the end of shelf life than was found in the other groups (Day 5 results: Day 0 irradiation: 75 +/- 32%; Day 3 irradiation: 45 +/- 45%; Day 5 irradiation: 47 +/- 41%; control: 40 +/- 24%; p<0.05).

CONCLUSION

Gamma radiation had no adverse effect on platelet quality in extremely WBC-reduced SDPs. On the contrary, a slight, but significantly better in vitro aggregability was found in SDPs irradiated before storage than in platelets irradiated later during storage and in unirradiated platelets. This increased in vitro aggregability persisted until the end of shelf life.

Evaluation of an automated system for the collection of packed RBCs, platelets, and plasma

BACKGROUND

This study evaluated the quality of WBC-reduced platelets, RBCs, and plasma collected on a new system (Trima, Gambro BCT) designed to automate the collection of all blood components. The study also evaluated donor safety and suitability of these components for transfusion.

STUDY DESIGN AND METHODS

In Phase I, the quality of the components collected on the new system was evaluated by standard in vitro and in vivo testing methods. Results were compared to those from control components collected by currently approved standard methods. In Phase II, additional collections were performed to evaluate the acceptability of the new system and the safety of platelets collected.

RESULTS

In vivo 24-hour RBC recovery was 76.8 +/- 3.1 percent for the test RBC units and 77.1 +/- 4.4 percent recovery for whole-blood (control) RBCs. The differences between test and control platelet results in the in vivo and in vitro assays were not clinically significant. Plasma clotting factors and fibrinogen levels met international standards. The system was well accepted by donors, and no major adverse donor reactions were reported for the 68 procedures performed. No problems were reported with transfusing the blood components collected.

CONCLUSION

Blood components collected with the Trima are equivalent to currently available components, and they meet the applicable regulatory standards. This system provides consistent, standardized components with predictable yields. It provides the option of fully automating the collection of all blood components.

Cytokines in WBC-reduced apheresis PCs during storage: a comparison of two WBC-reduction methods

BACKGROUND

Several studies have suggested that cytokine accumulation during storage of platelet concentrates (PCs) may mediate nonhemolytic febrile transfusion reactions and that a reduction in WBC numbers prevents the generation of cytokines. Despite efforts to minimize WBC contamination in apheresis PCs, high numbers of WBCs and increased cytokine levels may still occur, depending on the quality of the apheresis device employed.

STUDY DESIGN AND METHODS

This study was undertaken to investigate whether PCs collected with WBC-reduction devices (Spectra LRS, COBE;or MCS+ LDP, Haemonetics) were sufficiently depleted of WBCs to limit cytokine accumulation during storage. The study evaluated 1) the levels of cytokines of WBC and platelet origin in two types of apheresis PCs during storage and 2) the effects of prestorage filtration on cytokine levels in the Spectra LRS PCs.

RESULTS

In the Spectra LRS PCs, low levels of IL-6, IL-8, and monotype chemoattractant protein 1 (MCP-1) were detected in Day 1 PCs, and they remained consistent during the shelf life. RANTES, platelet factor 4 (PF4), beta-thromboglobulin (beta-TG), and transforming growth factor (TGF)-beta1 were also detected in these PCs, and their levels increased significantly on storage. Prestorage filtration of Spectra LRS PCs did not further reduce the levels of IL-6, IL-8, MCP-1, PF4, beta-TG, and TGF-beta1 in the filtered component. In the MCS+ LDP PCs, IL-6 was detected on Day 1, and its level increased significantly on storage, whereas the levels in the Spectra PCs remained steady. IL-8 levels were lower in MCS+ LDP PCs than in Spectra LRS PCs of the same age. MCP-1 levels were similar in both products on Day 1 and marginally increased in stored MCS+ LDP PCs. Substantial amounts of RANTES, PF4, beta-TG, and TGF-beta1 occurred in Day 1 MCS+ LDP PCs, and, on storage, these levels rose significantly.

CONCLUSION

Despite a significant reduction in levels of WBC-derived cytokines, platelet-derived cytokines were present in different amounts in the two products.

Periodic alternating interface positioning to lower WBC contamination of apheresis platelet concentrates: a multicenter evaluation

BACKGROUND

A new software version of a cell separator (AS TEC 204, Fresenius) providing WBC-reduced single-donor plateletpheresis concentrates was tested.

STUDY DESIGN AND METHODS

Dual-needle apheresis procedures (n = 621) were performed in three centers, using either fixed interface positioning (FIP) or periodic alternating interface positioning (PAIP). The other separation parameters (e.g., anticoagulant:whole-blood ratio, and blood flow) were set individually. All platelet concentrates were evaluated for platelet yields and contaminating WBCs.

RESULTS

The introduction of the PAIP resulted in a significant (p<0.001) reduction in contaminating WBCs (median, 30,000) from the numbers seen with FIP (median, 2,300,000) while maintaining the separation efficacy (47%) and separation time. Ninety-eight percent of all concentrates contained less than 5 x 10(6) WBCs per concentrate and 92 percent contained less than 1 x 10(6).

CONCLUSION

Plateletpheresis using the AS TEC 204 cell separator with PAIP is a valid alternative to WBC reduction by filtration. It may provide WBC-reduced platelet concentrates without the additional cost of filters. However, the reliability of the WBC reduction is not yet advanced enough that PAIP can be employed without any monitoring of the end product.

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

BACKGROUND

Important concerns with regard to in utero platelet transfusions are avoidance of volume overload and the immunomodulatory effects of residual white cells (WBCs). This study evaluated a modification of a leukocyte-reduction system (LRS, Spectra, COBE BCT) for apheresis, which collects high-concentration WBC-reduced platelets (HCPs) for in utero transfusion.

STUDY DESIGN AND METHODS

The LRS procedure was modified by running the platelet collection pump at specified low flow rates (Q(col)) for the first part of the procedure, collecting HCPs by gently purging them from the LRS chamber into a designated collection bag and then restoring the original LRS procedure settings to collect a second standard apheresis platelet concentrate (PC). Two centers carried out 32 procedures. Platelet yield, residual WBCs, and in vitro platelet function studies were evaluated.

RESULTS

Platelet concentrations in 60 mL of HCPs were predictable according to Q(col) (r(2) = 0.735). HCP yields varied from 0.9 to 3.2 x 10(11), depending on the desired final platelet concentrations in 60 mL, with an overall average of 1. 92 x 10(11) (n = 32). Apheresis PCs had a mean platelet yield of 2.9 x 10(11) (1.3-4.4 x 10(11), n = 20) and 3.9 x 10(11) (2.2-5.8 x 10(11), n = 12) at concentrations of 1.3 x 10(12) per L for single-needle and dual- needle procedures, respectively. Median WBC counts were 5.6 x 10(3) for HCPs and 2.0 x 10(4) for apheresis PCs, with >99 percent expected to be less than 1 x 10(6). HCP in vitro characteristics were equivalent to those of apheresis PCs at 24 hours after collection. In vitro performance declined over storage as a function of HCP yield. HCP pH at 22(o)C was maintained at a level of >6.2 for more than 3 days for yields >1.6 x 10(11), less than 2 days for yields 1.6 to 2.2 x 10(11), and less than 24 hours for yields >2.2 x 10(11). HCPs showed good in vitro characteristics and could be stored for 1 to 3 days, depending on the total number of platelets collected.

CONCLUSION

A standard apheresis PC and an HCP requiring no secondary processing can be collected with the Spectra LRS. The platelet concentration may be determined by clinical need. HCPs meet the requirements for components that are transfused in utero.

Cost effectiveness of quality assurance in plateletpheresis

BACKGROUND AND OBJECTIVES

A quality assurance system (QAS) is part of modern blood banking facilities. Quality control of single donor platelet (SDP) concentrates includes the determination of the platelet (PLT) yield and the white blood cell (WBC) contamination. Improvements in modern apheresis technology allow the collection of high PLT yields and leukoreduced products. Double dose SDPs can be split and WBC-reduced products may be labelled as leukodepleted thereby reducing costs.

MATERIAL AND METHODS

3309 SDPs obtained with the Amicus, AS 104, AS.TEC 204 and MCS + blood cell separators were retrospectively analysed for their PLT yield. SDPs with > or = 4.0 x 10(11) PLTs were considered as double dose SDPs and split. WBCs were determined microscopically in 170 SDPs. SDPs with a leukocyte content < 1.0 x 10(6) were labelled as leukodepleted and no further WBC filtration was recommended.

RESULTS

PLT yield was statistically higher in SDPs from the Amicus device, 84.8% of these products could be split. Double dose concentrates were collected in 22.7% with the MCS + machine and in 4.8% with the AS 104/AS.TEC 204 blood cell separators. The savings for disposables was $150,041 and for infectious disease testing $75,766. After the subtraction of the costs for PLT determinations in all SDPs $215,880 could be saved. WBC contamination was statistically lowest in in-line filtered SDPs from the MCS + device (median 0.29 x 10(5), range 0.22-9.96 x 10(5)) and all of these products were considered as fulfilling the criterion of leukodepeletion so that we were able to save $17,135 for bedside filters. Median WBC content was 0.75 x 10(5) (range 0.35-22.5 x 10(5)) in SDPs from the Amicus and 0.9 x 10(5) (range 0.27-99.8 x 10(5)) in SDPs from the AS 104/AS.TEC 204 devices, respectively.

CONCLUSION

Blood cell separators of the newest generation allow the collection of leukodepleted double dose SDPs. An intensified QAS in plateletpheresis allows the decision whether a product can be split and/or released as leukodepleted. By this means we were able to save a total of $233,015 per year.

Quality and clinical response to transfusion of prestorage white cell-reduced apheresis platelets prepared by use of an in-line white cell-reduction system

BACKGROUND

This study evaluated the quality and clinical effectiveness of white cell (WBC)-reduced apheresis platelets collected by the use of a new technology, fluidized particle-bed separation.

STUDY DESIGN AND METHODS

In phase 1, six suitable donors underwent two separate plateletpheresis procedures on one occasion, each separated by less than 10 minutes. In random order, a control unit was collected with the COBE Spectra and a test unit with the Spectra Leukocyte-Reduction System (LRS). The quality of apheresis platelet components was assessed by an in vitro test panel, and residual WBCs were counted by Nageotte chamber and flow cytometric methods. For the in vivo studies, the test and control units were randomly labeled with either 51Cr or 111In at the end of storage and transfused simultaneously to the donor. Samples were taken for calculation of platelet survival and recovery. In phase II, 109 thrombocytopenic patients were given platelets collected by use of the Spectra LRS.

RESULTS

Test platelets had significantly fewer residual WBCs (median 7.6 x 10(4)) than control platelets (median 3.9 x 10(5)), with equivalent in vitro function values. Test and control platelets had similar recovery and survival. Transfused platelets collected by use of the LRS achieved a mean 1-hour corrected-count increment of 19.3.

CONCLUSION

The LRS collects platelet components with significantly lower WBC contamination without adverse effects on the function or in vivo survival of the platelets.

The influence of automated plateletpheresis on systemic levels of hematopoietic growth factors

BACKGROUND

Megakaryocytopoiesis and platelet production are regulated by several hematopoietic growth factors. The present study focuses on the effects of automated plateletpheresis on systemic levels of different hematopoietic growth factors.

STUDY DESIGN AND METHODS

Platelet count, mean platelet volume, and serum levels of thrombopoietin, erythropoietin, interleukin-1beta, interleukin-6, and stem cell factor in 21 healthy donors were measured before platelet collection, after the first half of the apheresis procedure, at the end of apheresis, and on Days 1, 2, and 7 thereafter.

RESULTS

Thrombopoietin levels (initial level: 49.5 +/- 25.5 pg/mL) showed a significant increase between measurements taken at the end of apheresis and Day 1 (56.9 +/- 26.7 pg/mL; p = 0.01). There was a highly significant decrease in stem cell factor levels during apheresis (p<0.0005), reaching preapheresis values (1679 +/- 210 pg/mL) on Day 1. A highly significant increase in erythropoietin levels (initial level: 7.5 +/- 4.0 U/L) was seen after apheresis (p<0.0005 on Days 1 and 2). The level remained significantly elevated until Day 7 (p = 0.004). Interleukin-1beta and interleukin-6 levels (before donation: 1.4 +/- 1.8 pg/mL and 1.1 +/- 0.7 pg/mL, respectively) did not change during the observation period. Thrombopoietin levels correlated consistently and inversely with stem cell factor levels after apheresis (Day 1, r = -0.46, p = 0.035; Day 2, r = -0.50, p = 0.02; Day 7, r = -0.50, p = 0.02).

CONCLUSION

The data show a coordinated response of the hematopoietic system to platelet loss. It is suggested that the decrease in serum stem cell factor levels during apheresis reflects the consumption of stem cell factor by early hematopoietic progenitors that expand to initiate early megakaryocytopoiesis. The temporary increase in thrombopoietin is the result of platelet loss and serves as a stimulus for subsequent thrombopoiesis. The pronounced elevation of erythropoietin after apheresis suggests a role for this primarily erythropoietic cytokine in thrombopoiesis, too.

White cell reduction during plateletpheresis: a comparison of three blood cell separators

BACKGROUND

White cell (WBC)-reduced single-donor platelet concentrates (SDPs) can be collected by the newest generation of blood cell separators. Three WBC-reduction techniques during plateletpheresis were investigated in the present study with respect to WBC content and platelet yield.

STUDY DESIGN AND METHODS

The Amicus device used the elutriation principle for WBC reduction, and separations with periodically alternating interface position (PAIP) were employed in the AS.TEC 204. WBC reduction by in-line filtration was performed in the MCS+. Platelets were measured electronically and WBCs were determined manually (Nageotte chamber).

RESULTS

In-line filtered SDPs showed significantly lower WBC content (0.088+/-0.178 x 10(6)) than SDPs that were WBC reduced by elutriation (0.31+/-0.48 x 106) or PAIP technique (0.89+/-1.57 x 10(6), p = 0.0001). Platelet yield (5.0+/-0.46 x 10(11)) was significantly higher in components obtained with the Amicus device (p = 0.0001). The AS.TEC 204 and MCS+ gave similar results for platelet yields: 3.15+/-0.63 and 3.28+/-0.71 x 10(11), respectively.

CONCLUSIONS

The plateletpheresis systems studied allow the collection of WBC-reduced SDPs. In-line filtration resulted in the best WBC reduction. Some SDPs collected with the devices studied had a WBC content >1 x 10(6) per unit. Platelet yield was significantly higher in SDPs from the Amicus device.

A feasibility evaluation of an automated blood component collection system platelets and red cells

BACKGROUND

The purpose of these studies was to evaluate the functional properties of blood components collected with an automated collection system.

STUDY DESIGN AND METHODS

Single-donor platelets (n = 44) and packed red cell (RBC) units (n = 10) were collected. In vitro and in vivo assays were used to assess the function of single-donor platelet components stored for 5 days and of packed RBC units after storage for 42 days at 4 degrees C.

RESULTS

Adverse events observed in the 44 study subjects were minor. The mean 24-hour recovery value for the packed RBC units stored for 42 days was 83.6 +/- 5.4 percent, with a mean percentage of hemolysis on Day 42 at 0.46 +/- 0.19 percent. The 25 patients receiving platelet components achieved a mean corrected count increment of 15.1 +/- 10.4 x 10(3). All platelet concentrates had less than 1 x 10(6) total white cells.

CONCLUSION

Both in vitro and in vivo testing for the packed RBCs collected and stored for 42 days met the standards for both hemolysis and percentage of 51Cr 24-hour RBC recovery. The in vitro results and transfusion data on white cell-reduced platelet components transfused to thrombocytopenic patients were comparable to those on available platelet components.

Quantitative PCR for counting residual white blood cells in blood products

Leukocyte depleted blood components are frequently used to reduce alloimmunization and the risk of transfusion transmitted infection. Counting residual white blood cells in filtered blood products requires sensitive and reliable techniques. After separation of white blood cells from 500 microliters of 20 non-filtered and 54 filtered blood products we used polymerase chain reaction (PCR) and fluorimetric detection for the quantification of genomic DNA. The results were compared with results from Nageotte chamber counting. The accurate limit of detection of PCR was determined at 1 WBC/microliter (intra-assay coefficient of variation: 16.3%). PCR correlated well with Nageotte chamber counts (r = 0.77, p < 0.001, n = 74). Concordant results were obtained in 51 filtered and 20 non-filtered blood products. Discrepant results were obtained in 3 filtered whole blood units: In these blood products > 12 WBC/microliters were counted in Nageotte chamber and PCR gave a negative result. After component preparation fresh-frozen plasma and red cell concentrates of these units contained < 1 WBC/microliter using both methods. In conclusion we describe a quantitative PCR method which had about the same sensitivity and specificity as Nageotte chamber testing. However, PCR is more laborious than the standard method. As well, as reliable PCR testing requires expensive instruments and staff experienced in molecular biology, the standard method is more cost effective.

Quality assurance in thrombapheresis

The advent of comprehensive quality systems in blood banks and laboratory environment forces apheresis units to adherence to cGMP and cGLP. These constraints have brought apheresis centers to write standard operation procedures (SOPs) and operation flow charts, to train operators using training guides and to thoroughly document their work. An example of an SOP and an operation flow chart is given. We tested systematically the performance of three cell-separators (CS-3000 plus, Fenwal/Baxter; AS-104, Fresenius; Spectra with LRS, Cobe) employing 10 platelet apheresis (PCA) under daily working conditions and according to the SOP. We found few significant differences between the three apheresis systems, mainly caused by a greater processed blood volume in the CS-3000 group. Interestingly, we found no significant difference in the residual white blood cell (WBC) content per bag. With the AS-104 and the Spectra all products contained less than 1 x 10(6) WBC per bag. With the CS-3000 only 1 out of 10 contained WBC > 1 x 10(6) per bag. With each PCA a questionnaire was sent to the clinic asking for side effects. We observed no transfusion related side effects. The record keeping of different process parameters of platelet apheresis assures a constant quality of the product that is given by the national guidelines. Additionally, the present evaluation fostered operators' motivation into their work.

Clinical trial and local process evaluation of an apheresis system for preparation of white cell-reduced platelet components

BACKGROUND

A new method for the consistent preparation of white cell (WBC)-reduced plateletpheresis components, the Spectra Leukoreduction System (LRS), was evaluated by clinical trial and local process validation. The centrifuge-based system was projected to decrease the WBC content of plateletpheresis components to a level below 1 x 10(6) per unit. Phase I and II clinical trials were performed. The manufacturer's claims were then tested at the local level with an ongoing quality assurance program.

STUDY DESIGN AND METHODS

In Phase I, a cross-over analysis of five subjects compared LRS to standard plateletpheresis procedures in collection efficiency and component quality: a panel of in vitro measures was taken on Day 0 and Day 5. In Phase II, the LRS process was tested on a larger scale (n = 57; control = 58) with component transfusion. Finally, validation, determination of degree of conformance with standards, and ongoing quality control were performed locally on a newly installed instrument.

RESULTS

Phase I and II trials revealed no significant differences between LRS and control units in donor or recipient safety and comfort, platelet function and yield, or component volume. WBC per-unit values were significantly different: the LRS median per unit was 3.2 x 10(4) WBCs, versus 81.4 x 10(4) for control units. Assessment of process capability gave an estimate of 99-percent confidence that 99.5 percent of LRS units would be WBC reduced to < 1 x 10(6) WBCs. Local process validation and quality control revealed 90-percent confidence that 99 percent of the units would be WBC reduced and 99.9-percent confidence that 75 percent would exceed platelet yield standards; the process was stable over time.

CONCLUSIONS

The LRS is safe for apheresis and the component produced is safe for transfusion with platelet function and yield equivalent to controls and WBC reduction superior to controls. Local process evaluation confirmed that component quality meets the goals of the institution.

A survey of blood utilization in children and adolescents in a German university hospital

There are no detailed data on blood use with regard to diagnoses of recipients during infancy, childhood and adolescence. Available information on this issue is incomplete and no longer current. We conducted a survey of blood component use in children and adolescents in an acute-care university hospital in the greater area of Nuremberg between June 1994 and September 1996. Packed red blood cells (RBCs), fresh-frozen plasmas (FFPs) and platelet (PLT) components were evaluated for the recipients discharge diagnoses. Source study files were extracted from the hospital transfusion service and the medical records department. Transfused units were listed by broad diagnostic categories and leading diagnostic groups formed from principal diagnoses of the recipients according to the International Classification of Diseases, 9th edn (ICD-9). 34.3% of 2869 RBC cell units, 35.0% of 1095 FFP units and 5.0% of 1028 PLT components were used in patients with congenital diseases, mainly cardiac defects. The disease category neoplastic diseases was next most frequently associated with blood transfusion diagnosed in recipients of 23.9% of all RBCs, 15.6% of all FFP units and in 66.4% of all PLT units. Malignant diseases and benign haematological diseases (diagnostic categories II and IV) accounted for 68.9% of all costs of blood component transfusion. These findings demonstrate the increased importance of platelet transfusion for the organization of local and regional blood donation programmes and for cost analysis exercises. The study shows that detailed information on local blood use may be obtained quickly using available data collections of transfusion services and medical record departments.

Single donor platelets: can we afford to use them? Can we afford not to use them?

One of the strategies to reduce the risk of harming a patient by transfusion therapy is to limit the overall risk of transfusion-transmitted disease. Central to this approach is minimizing the number of allogeneic blood products with which a patient is transfused. The usual dose of platelets for an adult patient is either six to 10 random donor platelets vs. one unit of platelets, pheresis (so-called single donor apheresis platelets). Consequently, the transfusion services at the University of Southern California Health Sciences Campus (USC University Hospital, the Norris Cancer Hospital, and Los Angeles County + USC Medical Center) routinely use single donor apheresis platelets (SDPs) rather than random donor platelets (RDPs) in an effort to minimize allogeneic platelet transfusions, and thereby reduce risk of transfusion-transmitted infection. Although there are other compelling medical, technical, and medical-legal reasons to use SDPs instead of RDPs, the authors believe that a decrease in allogeneic donor exposures alone is sufficient reason to make SDPs the platelet component of choice at their institutions.