Abstract 20 A Rapid and Sensitive IL-3-Based Assay Reveals How Various Pre-Processing Conditions Affect the Potency of Hematopoietic Stem Cells in Fresh Cord Blood Units
Bibliographic record
Abstract
Abstract Introduction Optimized procedures to collect, process, and store cord blood (CB) units are crucial to ensure stem cell product quality; however, current methods to assess hematopoietic stem cell (HSC) potency are time-consuming or lack sensitivity. Therefore, developing methods that rapidly and accurately portray HSC potency in fresh blood is important to help optimize clinical outcomes. Objective We sought to adapt to fresh CB a potency assay previously developed for HSCs contained in cryopreserved CB [Simard et al. Transfusion. 2019;59(6):2074-2083.]. We next used the assay to evaluate the impact of various CB processing conditions on HSC potency. Methods Fresh CB units were exposed to various pre-processing storage conditions (ie, temperature changes and various anticoagulants). Units were then analyzed at various time points up to 96 hours using traditional iShage and colony-forming assays, in parallel with the IL-3-based potency assay. Results For CB units maintained at room temperature (RT), the potency measured with the IL-3-based assay (ie, the proportion of IL-3-responsive CD34+ cells as measured by pStat5 activation) linearly decreased over time. A potency of 69% was observed when tested within 0-24 hours, compared with 56% and 40% in the 24-48–hour and the 48-72–hour groups, respectively. In addition, the IL-3-based assay showed that pre-processing storage at 4°C prevented this loss of HSC potency. By contrast, the HSC count by iShage and the CFU numbers remained unchanged with time or temperature variations. Discussion The newly developed IL3-based assay appears reliable and sensitive to characterize the potency of CD34+ cells in fresh CB. In addition, this assay indicated that HSC potency linearly decreased with time when CB units were maintained at RT but remained stable when units were stored at 4°C pre-processing. This temperature-related difference was not observed with traditional assays, indicating that the test could be a complementary tool to characterize CB units in research and operational settings.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".