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Abstract

Blood Center/Blood Hospital-Based Donor Center

Oral Abstract - Storage Lesion

OA3-AM24-ST-13 - Platelet Components With Persistent Aggregates Are More Activated, Which Does Not Change Following Pre-transfusion Filtration: The BEST Collaborative Study

Saturday, October 19, 2024

9:45 AM - 10:45 AM

Location: 342

CE: Zero

Presenting Author(s)

DENESE C. MARKS, PhD

Research Program Leader- Product Development
Australian Red Cross Lifeblood
Alexandria, New South Wales, Australia

Disclosure(s): Vitrafy Life Sciences: Consultant/Advisory Board (Ongoing), Grant/Research Support (Ongoing)

PDF

Disclosure(s):

DENESE C. MARKS, PhD: Vitrafy Life Sciences: Consultant/Advisory Board (Ongoing), Grant/Research Support (Ongoing)

Background/Case Studies: Platelet components (PCs) from some donors have a greater tendency to form persistent aggregates, which have a more activated phenotype. These units are typically discarded. However, PCs with smaller or fewer aggregates may be less activated, and could potentially be retained to reduce wastage. Further, the effect of removing aggregates with pre-transfusion filtration has not been assessed. A multicenter study was conducted to address these questions.

Study

Design/Methods: Eight international centers participated in the study. Seven centers collected apheresis PCs and one collected pooled (whole-blood derived) PCs, which were analyzed separately. PCs with persistent aggregates (n=157) and without (controls; n=75) were tested on day 4 or 5 post-collection. PCs were assigned a score using a matrix based on the size and number of aggregates, ranging from 0 (no aggregates) to 24 (many large aggregates). Platelet count, metabolism, membrane and soluble activation markers (annexin-V, CD62P, microparticles, glycocalicin and prothrombin F1+F2 fragments) and function (collagen aggregation) were measured. A sub-set of PCs (aggregates n=62; controls n=38) were filtered through a 200 µm transfusion set, and pre- and post-filtration results were compared. Data sets from apheresis platelets were analyzed using a mixed model of linear regression to account for inter-site variation, comparing aggregates and controls. Data from whole blood platelets were analyzed using unpaired t-tests. p< 0.05 was considered significant.

Results/Findings: The median aggregate score in PCs with aggregates was 8 (IQR 8). Of these, 74 (47%) PCs had an aggregate score < 6, 63 (40%) had aggregates with a score of 7 to 15, and 21 (13%) PCs had a score > 15. PCs with aggregates had similar platelet counts and pH to controls, although the glucose concentration was significantly lower and lactate was significantly higher in PCs with aggregates (Table 1). Platelets in PCs with aggregates were more activated, with significantly higher CD62P, annexin-V and CD61/annexin-V-positive microparticles. However, there were no differences in collagen aggregation, glycocalicin, or prothrombin F1+F2 fragments in PCs with aggregates compared to controls (Table 1). There were no significant differences in whole blood platelets for any parameters. Filtration successfully removed aggregates. However, the activated platelet phenotype did not change. There were no significant differences in any parameters from PCs with an aggregate score of ≤6 (2-5 aggregates, < 3-5 mm) when compared to controls.

Conclusions: Platelets in PCs with aggregates are significantly more activated with higher glucose metabolism. Filtration effectively removes aggregates, but does not change the platelet phenotype. The presence of a low number of small aggregates is unlikely to adversely affect the quality of PCs, which could be considered for transfusion if filtered.