(P-BT-12) Comparative Analysis of Cellular Starting Material from Residual Leukocyte Units Processed via the Terumo Reveos^TM Automated Blood Processing System versus Trima Accel^TM LRS Chambers

Background/Case Studies: The Reveos^TM Automated Blood Processing System (Terumo BCT) is the first FDA-cleared platform capable of fully automated centrifugation, optical-guided separation, and leukoreduction of up to four whole blood units per cycle. A unique byproduct of this process is the residual leukocyte unit (RLU), which results from the expression of the buffy coat from whole blood, thereby reducing leukocyte load prior to leukofiltration. Functionally, RLUs are analogous to leukoreduction system (LRS) chambers from the Trima Accel^TM apheresis platform, although their cellular compositions have not been rigorously compared. This study presents the first direct comparative analysis of hematocrit, total nucleated cells (TNC), mononuclear cells (MNC), and volumetric yields between Reveos-generated RLUs and LRS chambers collected from Trima Accel apheresis procedures.

Study

Design/Methods: We analyzed 80 RLUs produced by the Reveos using 2.0 software and Lumia^TM management tools from standard whole blood donations processed under the 2C and 3C component protocols. Complete blood counts were performed on undiluted samples using the SYSMEX XN-10 analyzer.

For comparison, 23 LRS chambers were obtained from eligible donors undergoing Trima Accel apheresis procedures (platelet or platelet/plasma) with rinseback. Each chamber was drained, air-flushed and evaluated using both undiluted and 1:20 diluted samples on the SYSMEX XE-2100. Inclusion criteria for LRS chambers included: volume ≥ 6 mL, PBMC content ≥ 90%, and TNC ≥ 0.5 x 10⁹. Data were analyzed using Welch's t-test. All blood products were collected with the donor's informed consent.

Results/Findings: Significant differences in cellular composition and volume were observed between Reveos RLUs and Trima Accel LRS chambers (Table 1). Reveos RLUs yielded higher average volume (14.98 mL vs. 8.20 mL) and neutrophil content (44% vs 5%), whereas LRS chambers had higher concentrations of peripheral blood mononuclear cells (PBMCs: 1.49 x 10⁹ vs. 0.78 x 10⁹), lymphocytes (69% vs. 40%), and monocytes (26% vs. 11%). Hematocrit (mean ≈ 60%) and TNC counts (mean = 1.56 x 10) were comparable between groups. All between-group differences were statistically significant (p < 0.0001), except for hematocrit and TNC.

Conclusions: Reveos-derived RLUs yield greater volume and are richer in neutrophils than LRS chambers from Trima Accel apheresis, while maintaining similar hematocrit and total nucleated cell counts. These distinctions have key implications for transfusion support and use as starting material in cell therapy manufacturing. Further investigation into the viability and activation of specific leukocyte subsets—such as T cells, B cells, NK cells, and monocytes—within RLUs will provide insight into their functional utility. Collection method, additive solution, and anticoagulant may also influence the efficacy and suitability of cellular starting material and warrant further study.