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Updated: Jan 19, 2026
Preparation of Peripheral Blood Mononuclear Cell Pellets and Plasma from a Single Blood Draw at Clinical Trial Sites for Biomarker Analysis
Published on: March 20, 2021
Intra-procedure white blood cell monitoring as a predictor of collection efficiency in mononuclear cell apheresis
Austin Choi1, Shasta Theodore1, Yanyun Wu1
1University of Miami Miller School of Medicine, Department of Pathology and Laboratory Medicine, United States.
Background:
Efficient collection of cellular starting material is critical for the success of chimeric antigen receptor T-cell (CAR-T) therapy. While hematopoietic progenitor cell (HPC) harvests rely on pre-procedure CD34⁺ counts to predict adequacy, equivalent real-time predictors for mononuclear cell (MNC) collections remain lacking. This study evaluated intra-procedure white blood cell (WBC) concentration as a potential indicator of collection performance.
Methods:
A retrospective review was conducted of CARVYKTI MNC apheresis procedures performed between July 2023 and November 2024 at the University of Miami, Sylvester Comprehensive Cancer Center. Institutional Review Board approval was obtained (protocol #20201331). Pre-procedure peripheral WBC counts (ppWBC), intra-procedure WBC concentrations (ipWBC), total blood volume processed (TBVIP), and collection efficiency (CE) were analyzed. Correlations were assessed using Spearman's rank coefficients.
Results:
Forty-seven procedures were analyzed. Median ppWBC was 4.5 × 10³/µL (IQR 3.6-6.4), median ipWBC 75.8 × 10 ³ /µL (IQR 49.4-97.2), and median CE 0.21 (IQR 0.17-0.26). ipWBC showed strong positive correlations with ppWBC (r = 0.68, p = 1.7 ×10⁻⁷) and CE (r = 0.54, p = 9.0 ×10⁻⁵), whereas ppWBC alone did not correlate with CE (r = -0.14, p = 0.35).
Conclusions:
Intra-procedure WBC concentration correlates with collection efficiency and provides a more meaningful real-time indicator of MNC harvest performance than pre-procedure counts alone. Incorporating intra-procedure monitoring into apheresis workflows may enhance yield predictability and streamline CAR-T manufacturing logistics.
