Paired comparison of apheresis platelet function after storage in two containers

Monitoring of platelet activation in platelet concentrates using transmission electron microscopy

OBJECTIVE

The quality of platelet concentrates (PC) is important for the in vivo recovery of thrombostasis in patients suffering from bleeding disorders and in tumor patients after chemotherapy. In this respect, activated platelets (PLT) cannot display their full functionality in the recipient and even can cause adverse effects. Therefore, we developed a transmission electron microscopy (TEM) method for quality assessment of PC.

METHODS

Score values taken from panorama TEM images describe the progress of PLT activation. To exemplify this method, i) 19 apheresis PC isolated with the Baxter Amicus system (BA) were compared with 14 PC obtained from pooled buffy coats (BC). ii) The score values of 33 PC derived from BA as well from BC were compared with flow-cytometric CD62P determinations by cross correlation. iii) Changes in the score value profiles during storage of a single pathogen-reduced BA PC were monitored over a period of 7 days.

RESULTS

The TEM evaluation described allows for demonstrating particular PLT activation stages. i) Significant differences between the percentages of the score values 0, 1 and 2 could be demonstrated in both processing groups. No significant differences were found comparing these two groups. ii) A weak correlation could be shown when comparing the percentages of score values 2 plus 3 with the percentage of CD62P-positive PLT. iii) The pathogen reduction affected slightly the score profiles during storage due to an increase of dead PLT.

CONCLUSION

Our investigations demonstrate the unique detailed quality information of PC obtained by the TEM method. This method can be performed in every routine electron microscopy laboratory.

Short-term liquid storage of CD14+ monocytes, CD11c+, and CD123+ precursor dendritic cells produced by leukocytapheresis

BACKGROUND

This prospective study compared white blood cell (WBC) storage in polyvinylchloride (PVC) bags and in polyolefin (POF) bags. After leukapheresis, CD14+ monocytes, CD11c+, and CD123+ precusor dendritic cells (DCs) were analyzed under platelet (PLT) storage conditions.

STUDY DESIGN AND METHODS

Twenty-five leukapheresis procedures were performed on blood cell separators (AS.TEC204 [PVC; Fresenius HemoCare GmbH] and the COBE Spectra [POF, Gambro BCT]). Blood cell counts, glucose, lactic acid, pO(2), pCO(2), and pH were measured in mononuclear cell (MNC) harvests on Days 0, 1, 3, and 5. WBCs were analyzed by flow cytometry.

RESULTS

The WBC yields of the AS.TEC204 harvests were 25 percent higher (13.4 x 10(9) +/- 2.7 x 10(9) WBCs) compared to the COBE Spectra (9.9 x 10(9) +/- 2.5 x 10(9) WBCs). During 5-day storage, WBC counts (PVC bags) decreased significantly (24%). Storage in POF bags showed more consistent results (WBC loss, 6%). Loss of CD14+ monocytes and CD11c+ precursor DCs did not differ significantly in leukapheresis products. CD123+ precursor DCs stored in PVC bags dropped by more than 90 percent (POF bags, 24%). Lactic acid concentrations exceeded 20 mmol per L after 24 hours in PVC bags and after 72 hours in POF bags. The mean pH value on Day 5 was 6.2 (PVC) and 6.3 (POF). On Day 1, the product glucose concentration decreased by 76 percent after storage in PVC bags and by 16 percent in POF bags.

CONCLUSIONS

Storage of MNCs within 72 hours in the original harvest container assures stable WBC content and is easy to perform. POF bags should be preferred in the case of extended WBC storage. Patient studies should clarify changes in efficiency of hematopoietic reconstitution that might occur over time during MNC storage.

Plateletpheresis does not cause long-standing platelet-derived growth factor release into the donor blood

BACKGROUND

Recently, long-standing elevations of soluble growth factors released from platelets (PLTs) after contact with artificial surfaces during dialysis were described. They could be jointly responsible for the high frequency of death from cardiovascular diseases in dialysis patients. There are no comparable data on the extent and the duration of a growth factor release by plateletpheresis procedures.

STUDY DESIGN AND METHODS

A total of 37 plateletpheresis procedures were performed with two different devices. PLT-derived growth factor (PDGF) isoform AB, transforming growth factor (TGF)-beta1, and beta-thromboglobulin (beta-TG) were measured in the donors' plasma samples, and PLT activation and function were measured by cytometry and aggregometry before and after plateletpheresis and 1 and 24 hours later.

RESULTS

Before apheresis, the following mean plasma levels were found: beta-TG, 98.6 +/- 37.3 IU per mL; PDGF-AB, 71.5 +/- 38.5 pg per mL; and TGF-beta1, 2.24 +/- 0.80 ng per mL. At the end of the apheresis procedures, the mean PDGF-AB level had increased by a factor of 1.8 (p < 0.05). One hour later, the mean PDGF-AB level had normalized again. No significant change in the levels of beta-TG and TGF-beta1 was found by the apheresis procedures. There was no influence of the blood cell separator type on the results.

CONCLUSION

Only a slight and rapidly reversible increase in soluble PDGF-AB was found during plateletpheresis and no increase in soluble TGF-beta1 and beta-TG was found. This change should not be harmful to the donor.

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.

Improved extension of platelet storage in a polyolefin container with higher oxygen permeability

This study evaluated a newly developed polyolefin bag, which has a 50%/m(2) higher oxygen permeability to extend the shelf-life of platelets. Single-donor aphaeresis platelets were pooled, separated equally into two bags, PO-80 (0.8 l capacity) and KBP-PO (1 l capacity) for control, and stored in plasma for up to 7 d. Platelet biochemical and functional parameters were monitored in bags containing high (4.2 x 10(11)/250 ml/bag, n = 9) and low (2.0 x 10(11)/200 ml/bag, n = 3) concentrations of platelets over the storage period. After 7 d of storage, the PO-80 bags containing high concentrations of platelets had a better pH (mean pH 6.74) than those stored in KBP-PO (pH 6.32, P < 0.01); none of the nine PO-80 bags with a high platelet concentration had a pH below 6.2, compared with four of nine controls (P < 0.05). Similarly, lactate values were 20.19 mmol/l and 28.09 mmol/l respectively (P < 0.05). Aerobic metabolism was maintained better with greater O(2) consumption and less lactate generation in high-platelet concentration PO-80 bags than in the control bags. A significant difference was also found in pH, pCO(2) and lactate levels between the two bags containing low concentrations of platelets during the 7-d period. The in vitro characteristics of platelets declined less over 7 d when stored in a higher oxygen permeable container than in a marketed bag.