Circulating Blasts Are Associated with High Levels of vWF and Thrombin Activation in Children with Newly Diagnosed ALL.
Bibliographic record
Abstract
Abstract Background: Children with acute lymphoblastic leukemia (ALL) are known to have thrombin activation at diagnosis. However, the pathophysiology of thrombin generation and the impact of therapy on thrombin activation are so far unknown. Steroids are shown to induce prothrombotic state by increasing prothrombotic factors and reducing fibrinolytic potential. The investigational window on DFCI 05-01 protocol offered an unique opportunity to study the haemostatic effects of prednisone, independent of previous or concurrent therapy, in children with newly diagnosed ALL. Aims: In children with newly diagnosed ALL, To evaluate the effects of methyleprednisone monotherapy (PMT) (32 mg/m2/day IV for 3 days) on the parameters of thrombin generation [prothrombin fragments 1.2 (F1.2), thrombin-antithrombin complex (TAT), and D-Dimer], fibrinolytic potential [plasminogen, tissue plasminogen activator (tPA), alpha-2 antiplasmin, alpha-2 macroglobulin, plasminogen activator inhibitor-1 (PAI-1), ratio of tPA/PAI-1], and coagulation factors [FVIII:C, von Willebrand factor (vWF) and fibrinogen] To study the effect age at diagnosis (< 10 Vs ³ 10 years), gender, risk categorization of ALL [standard (SR) Vs high risk (HR)], presence or absence of circulating blasts, presenting white cell and platelet count on the above hemostatic factors pre and post steroid therapy Methods: Children (> 1 to £ 18 years of age) enrolled on DFCI ALL 05-01 protocol, without prior steroid therapy or presence of clot, were eligible for study. Overnight fasting blood samples was collected prior to and after PMT, and analyzed for hemostatic factors. The change in the level of each of the hemostatic parameters following PMT was expressed as percent increase or decrease from the baseline. The effect of steroids was tested using “paired t test”. To assess the effects of patient and disease variable student’s t-test was used. Results: Of 30 patients (13 females) enrolled, 8 (27%) had HR ALL. The mean age was 6.33 years (SD 4.35); 24 patients were < 10 years. At baseline the levels of F1.2 (mean 1.54 nmol/L; SD 0.90), TAT (mean 10.90 microgram/L; SD 14.93) and D-dimers (2,766.03ng/mL; SD 2385.82) were increased indicating endogenous thrombin activation. Patients with circulating blasts (n=17) had significantly higher mean levels of vWF [1.89 (0.61) vs. 1.14 (0.48) p=0.001], TAT [15.39 (18.62) vs. 5.02 (3.29) p=0.038] and D-dimer [3640 (2499) vs. 1623 (1711) p=0.019] compared to those without circulating blasts. For children with circulating blasts at diagnosis, following steroid therapy the blast count decreased significantly from 24.2% to 3.5% (P<0.001)) with reduction in level of vWF, TAT and D-dimer (Table1). Conclusions: Patients with circulating blasts had significantly higher baseline level of vWF, TAT, and D-dimer compared to those without circulating blasts. Following steroid therapy there was reduction in circulating blast count and significant reduction in vWF (despite increase in VIII:C levels), TAT and D-dimer whereas children without circulating blasts had increased levels of vWF, FVIII:C, TAT and D-dimer. We postulate that circulating blasts lead to endothelial activation (with vWF production) which in turn activates the coagulation system with resultant thrombin generation. In children with newly diagnosed ALL, PMT has two-fold hemostatic effects, a direct effect inducing procoagulant state and an indirect effect through reduction of blasts. Table 1. Effect of PMT on hemostatic factors in patients with and without circulating blasts Parameters Blasts Presents (n=17) Blasts absent (n=13) Pre-PMT Post-PMT % change from baseline (95% CI) P value Pre-PMT Post-PMT % change from baseline (95% CI) P value VWF 1.89 1.5 −19.5 (−27.9, −11.1) <0.001 1.14 1.25 15.6 (−6.0, 37.2) 0.142 F VIII:C 1.45 1.8 31.2 (11.2, 51.3) 0.005 1.3 1.63 27.5 (13, 42) 0.002 TAT 15.4 8.9 − 41.9 (−65.1, 148.9) 0.417 5.02 6.4 50.0 (−6.6, 106.7) 0.078 D-dimer 3640 2509 − 23.8 (−43, −4.6) 0.018 1622.6 2137.2 120.4 (−75.8, 316.6) 0.206
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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 | 0.000 | 0.001 |
| 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) | 0.001 | 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 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".