Studies on the improvement of leucodepletion performance of the Haemonetics MCS+ for production of leucodepleted platelet concentrate

Improvement of plateletpheresis via technical modification on the MCS+

BACKGROUND

With the advantage of easy operation and high reliability, Haemonetics multicomponent collection system (MCS+) is widely used as a blood cell separator in clinical application.

OBJECTIVES

The aim of this study was to evaluate the effect of technical parameter modification as utilised on the MCS+ to improve the quality of platelet yielded as well as donor comfort.

METHODS

After informed consent, a total of 118 donors, well matched for baseline parameters, were included in the study from December 2012 to April 2013. Sixty-one donors underwent single-dose plateletpheresis (SDP), and the other 57 donors underwent double-dose plateletpheresis (DDP) before and after technical modification on the MCS+, respectively, according to the manufacturer's instructions. The procedures were evaluated, focusing on whole blood processed (WBP), processing time (PT) and number of cycles were measured, as well as the quality of products.

RESULTS

No severe adverse reaction was found during donation. WBP, PT and number of cycles after modification were all reduced significantly in both SDP and DDP groups (P < 0·01). In addition, 80·51 % (95 in 118) of the total post-modification products were qualified, presenting with high quality. Besides, the comfort of donors was also improved probably because of the reduced PT.

CONCLUSION

Adjustment of the relevant technical parameters on MCS+ could produce a beneficial effect on the procedure measures and ensure a high-quality platelet production.

A new platelet storage lesion index based on paired samples, without and with EDTA and cell counting: Comparison of three types of leukoreduced preparations

Platelets derived from whole blood and diverse apheresis procedures come in contact with various artificial surfaces and undergo contact activation, sheer stress-induced shape changes, aggregation and microvesiculation during collection, processing and storage. These dynamic changes are qualitatively reflected in the log-normal platelet size distribution patterns seen, when using modern automated cell counters and can be measured quantitatively by counting the paired samples, without and with added EDTA, and calculating the differences (d) in platelet cellular indices (dPLT/dMPV/dPDW). Reporting the differences instead of the absolute values of cellular indices makes the measurements independent of basic principles used for cell counting (i.e. aperture-impedance or flow-optic). The measurements can be performed either in blood centres, hospital blood banks or nearby patient clinics equipped with a validated cell counter. At least three useful quality indices could be derived simultaneously from this procedure (accurate estimation of platelet yields using the value of the EDTA-containing sample); quantitative assessment of the % of reversible platelet aggregates, an age/pH/temperature-dependent degree of microvesiculation/apoptosis/PS exposure, based on the response to EDTA. This new set of indices correlate significantly with other conventional tests for platelet quality; hence, provide additional supportive evidence for confirming the low pH values and the subjective poor swirling data occasionally seen with stored PC. In the following study, the Sysmex SE 9000 was successfully employed for estimation of platelet cellular indices comparing the platelet storage lesion index of three types of leukoreduced platelet concentrates in current practice. The relationship between this in vitro response to clinical outcome remains to be established.

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.

Universal leucodepletion: an overview of some unresolved issues and the highlights of lessons learned

Universal leucodepletion (ULD) has been introduced in several countries based on the evidence that selective leucodepletion improves the clinical safety of blood components and based on animal studies that TSE infectivity is 5-7 times higher in the buffy coat than in plasma. Therefore it is perceivable that the removal of the buffy coat, by filtration, removing both leucocytes and platelets, may prove beneficial in reducing the potential risk of transmission of variant CJD by blood components. The implementation of a ULD policy has created some new requirements: Validation/standardisation of various leucodepletion processes to ensure compliance with set specifications. Standardisation/harmonisation of sampling and low leucocyte counting technologies to ensure the interchangeability of results nationally. The establishment of external quality assessment schemes on 'real' leucodepleted products where the cells come in contact with the filter matrix, to monitor the low leucocyte counting performance, nationally. Assessment of filtration-induced generation/retention of major biological response modifiers (BRM), having potential for the development of transfusion reactions. Using these approaches we have identified that, while the overall leucodepletion performance has improved following harmonisation/standardisation of the operational and counting technologies, there are still some unresolved problems and ULD alone may not provide complete protection from some viral transmission such as HTLV and CMV infections or reduction of bacterial sepsis and generation of some BRM. Moreover, ULD has not fully abrogated febrile non-haemolytic transfusion reactions (FNHTR). Therefore the key issue is not the 3-4 log(10) reduction of residual leucocytes but the design of new generation filters or leucodepletion processes with better performance characteristics, to further reduce some specific leucocyte subsets and their fragments as well as reduce the activation of coagulation/complement/kinin and inflammatory systems. Efforts should also be made to reduce the rapid development of apoptotic/necrotic cells and the residual risk associated with plasma, which often contains a vast array of BRM, responsible for residual transfusion reactions. These could only be effectively achieved by working in cooperation with the suppliers of blood component technologies. This overview briefly highlights some of the unresolved issues related to ULD, based on the experience in the UK. Technical details can be found in the reading list provided at the end.

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.

Validation of different enrichment strategies for analysis of leucocyte sub-populations: development and application of a new approach, based on leucofiltration

Characterisation of the nature of leucodepletion failure, based on the analysis of leucocyte sub-populations, is an essential task for continual improvement in the clinical safety of blood components and for the selection of a safe and appropriate leucodepletion process. Such information is also critical for improving the quality of filters through an understanding of the mechanism of leucocyte removal filters. Unfortunately, the residual leucocytes of filtered blood components are around the sensitivity of current leucocyte-counting technologies, hence a need for an enrichment process. This preliminary report deals with the merits of various WBC enrichment strategies for the analysis of WBC sub-population subsets. A new procedure, based on refiltering and backflushing the content, with up to 30-fold enrichment, is described. This one-step procedure has the advantage of concentrating both native and atypical leucocytes seen in blood components. The latter may account for lack of interchangeability of results obtained by various counting methods.

The quality of MCS+ version C2 double dose platelet concentrate with leucodepletion through a continuous filtration process

182 full double donations were collected, using 7-9 cycles with an in-house guideline based on donor HCT, and platelet count. 95.6% of donations were within specifications for platelet yield and 100% were leucodepleted. To overcome the potential for red cell spill-over when the platelet peak is too small, automated continuous monitoring of machine performance has been introduced reducing the potential for spill-over. To understand the impact of the continuous exposure of platelets to the filter, the quality of the first and second part of the collection was monitored using a new set of markers for the platelet storage lesion (activation, microvesiculation, cellular injury, complement and response to ADP). The results were equivalent and compared well with routine practice. Our new protocol allows a wide range of donors to be selected and the highest percentage of products to meet the UK specification with consistency. It is recommended that it can be used for double dose platelets with routine SPM.