Severe bleeding diatheses in an elderly patient with combined type autoantibody against factor <scp>XIII</scp> A subunit; novel approach to the diagnosis and classification of anti‐factor XIII antibodies
Bibliographic record
Abstract
Introduction Acquired factor XIII ( FXIII ) deficiency due to autoantibody is a rare, severe bleeding diathesis. Its laboratory diagnosis and classification represents a difficult task. Aim Introduction of novel approaches into the diagnosis and characterization of anti‐ FXIII autoantibody and demonstration of their use in the diagnosis of a patient with autoimmune FXIII deficiency. Methods Factor XIII activity, FXIII antigen levels and the titre of anti‐ FXIII ‐A antibody were monitored throughout the course of the disease. FXIII activity was measured by ammonia release assay; FXIII ‐A 2 B 2 complex, total and free FXIII ‐B concentrations were determined by ELISA s. The binding constant for the interaction of the autoantibody with recombinant FXIII ‐A 2 ( rFXIII ‐A 2 ) and FXIII ‐A 2 B 2 was determined by surface plasmon resonance ( SPR ). The inhibitory capacity of IgG was expressed as the concentration exerting 50% inhibition of FXIII activation/activity ( IC 50). The truncation of FXIII ‐A by thrombin was monitored by western blotting. The inhibition of Ca 2+ ‐induced FXIII activation and active FXIII ( FXIII a) were assessed by FXIII activity assay. Results The antibody bound to rFXIII ‐A 2 and FXIII ‐A 2 B 2 with high affinity and accelerated the decay of supplemented FXIII concentrate. An IC 50 value of 170.1 μg IgG·mL −1 indicated effective FXIII neutralization. The main neutralizing effect of the autoantibody was the inhibition of FXIII a. After 2 months, due to combined therapeutic modalities, the autoantibody disappeared and FXIII activity significantly elevated. Conclusion The anti‐ FXIII ‐A autoantibody exerted a combined effect including inhibition of FXIII a and acceleration of FXIII decay in the plasma. IC 50 and binding constant determinations added important information to the characterization of the autoantibody.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 | 0.001 |
| 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".