670. Combined Strategy of Minimal Myeloablation and Optimal BMT Regimen To Cure Murine β-Thalassemia
Bibliographic record
Abstract
Using a thalassemic mouse model (hemi-βthal mouse) deleted from the two adult genes in the β-globin locus and reproducing the human β-thalassemia intermedia, we have recently established by a competitive repopulating assay that only 19 to 24% normal bone marrow cells transplanted into lethally irradiated hosts was sufficient to significantly correct the disease. Based on this finding, we hypothesized that a minimal level or absence of myeloablation could be used for therapeutic correction of β-thalassemia and thus, investigated this minimal level as well as the optimal cell transfer conditions to achieve such treatment. A series of bone marrow transplantations was performed on 51 partially irradiated (100 or 200 Rads) hemi-βthal mice divided into 8 groups of 5 to 8 chimeric mice each. The hemi-βthal mice received 20, 40, or 60 million nucleated bone marrow cells in either one dose or two equal doses given at 24h difference. Engraftment and chimerism of hemi-βthal recipient mice were analyzed for short and long-term post- transplantation (2 months to >6 months) using the Gpi1a marker. When one cell dose was given to mice conditioned with 100 Rads, no mice (0/6) engrafted with 40 million cell whereas 42.8% of mice (3/7) engrafted with 60 million cells at 23% mean chimerism in the latter group. Of interest, mice conditioned with 200 Rads showed significantly more engraftment from 50% (4/8 mice, 20 million cells) to 85% (6/7 mice, 40 million cells) leading to 36% and 66% mean chimerism, respectively. Most importantly, when mice conditioned with 100 Rads received two half-doses of cells at 24 hour difference, the engraftment increased from 42.8% (3/7 mice, 2 × 20 million cells) to 100% (6/6 mice, 2 × 30 millions cells) with 40 and 48% mean chimerism respectively, while mice conditioned with 200 Rads showed 80% engraftment (4/5 mice) for 20 and 40 million cells transferred, with 63 and 84% mean chimerism respectively. Mice with 23% bone marrow chimerism showed significant improvement of most hematological parameters on complete blood count (CBC) and of all parameters with chimerism greater than 36%, consistent with our recent findings. Altogether, our results established 100 Rad irradiation and two-cell doses as the minimal therapeutic requirements for optimal engraftment and chimerism. Significantly, this is the first study to determine a transplantation strategy in minimally ablated thalassemic mice to attain 100% engraftment efficiency and a therapeutic chimerism in all mice, constituting a basis amenable to clinical applications for human thalassemia.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".