Bone Marrow Specimens From Patients with Immune Thrombocytopenia (ITP) Demonstrate Increased Megakaryocyte-Bound IgG and Increased T-Helper Cells
Bibliographic record
Abstract
Abstract Abstract 2233 BACKGROUND: Immune thrombocytopenia (ITP) is a heterogeneous autoimmune disease characterized by low platelet counts and platelet autoantibodies. The mechanisms of ITP remain unclear although recent evidence suggests that megakaryocytes may be the target of immune destruction. To test this hypothesis we evaluated IgG-binding to megakaryocytes and B- and T-cells in bone marrow specimens of ITP patients and non-thrombocytopenic controls. METHODS: Histological slides of bone marrow biopsies from ITP patients and control patients were prepared from stored paraffin-embedded tissue blocks for blinded pathological assessment. Adult ITP patients (N=19) had a platelet count less than 100 x109/L (range 2 – 76 x109/L) as measured within 4 weeks before the date of bone marrow biopsy procurement without splenomegaly, myelodysplastic syndrome, lymphoproliferative disease, HIV, hepatitis B or C, drug-induced thrombocytopenia or prior treatment with thrombopoietin receptor agonists or other hematopoietic growth factors. Control patients (N=15) were adults with limited stage lymphoma or monoclonal gammopathy of undetermined significance with a normal platelet count (150 – 400 x109/L) who had a bone marrow biopsy for staging purposes which was reported as normal. Patients with prior use of anti-neoplastic agents or hematopoietic growth factors were excluded. Coded bone marrow biopsy sections were labeled with rabbit polyclonal anti-IgG, anti-CD4, anti-CD8, anti-CD20, and CD61 in serial sections, followed by streptavidin-biotin labeling techniques. The intensity of staining was assessed semi-quantitatively by an experienced hematopathologist for megakaryocyte, B-cell and T-cell numbers (increased, decreased, within normal limits) and megakaryocyte-bound IgG (negative, below 50% of cells positive or more than 50% of cells positive) blinded to diagnosis and platelet count. RESULTS: ITP bone marrows demonstrated greater IgG binding to megakaryocytes compared with controls [12/19 (63.16%) vs. 4/15 (26.67%), p=0.02], increased CD4+ cells [15/19 (78.95%) vs. 5/15 (33.33%), p=0.003] and marginally increased CD8+ cells [11/19 (57.89%) vs. 4/15 (26.67%), p=0.05]. B-cell numbers were not different between groups. CONCLUSIONS: Using bone marrow specimens from carefully selected ITP patients and controls, our study shows that IgG-bound megakaryocytes and T cells, especially T-helper cells, are increased in bone marrow of ITP patients compared with controls. These data provide evidence of megakaryocyte injury in ITP. Additional labeling with caspase-3 and TUNEL stains is planned to identify markers of apoptosis. Disclosures: Kelton: Amgen: Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Research Funding. Arnold:Amgen: Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Research Funding; Talecris: Honoraria; Hoffmann-LaRoche: Research Funding.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".