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Platelet-activating anti-PF4 disorders: An overview

2022· review· en· W4212938842 on OpenAlex
Theodore E. Warkentin

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueSeminars in Hematology · 2022
Typereview
Languageen
FieldMedicine
TopicHeparin-Induced Thrombocytopenia and Thrombosis
Canadian institutionsMcMaster UniversityHamilton Regional Laboratory Medicine ProgramHamilton Health SciencesHamilton General Hospital
Fundersnot available
KeywordsPlateletMedicinePlatelet factor 4PharmacologyImmunology

Abstract

fetched live from OpenAlex

Platelet factor 4 (PF4) is a highly cationic tetrameric protein that can be targeted by platelet-activating anti-PF4 antibodies of immunoglobulin G (IgG) class. Certain features of PF4, including its multivalent nature (duplicate antigen sites per tetramer), the ability of many PF4 tetramers to undergo close approximation through charge neutralization, and the dimeric binding of IgG molecules, results in formation of IgG-containing immune complexes in situ on platelets, neutrophils, and monocytes, resulting in Fcγ receptor-mediated pancellular activation that also activates hemostasis (potential for disseminated intravascular coagulation). This review discusses 4 anti-PF4 disorders: classic heparin-induced thrombocytopenia ([HIT]; triggered by heparin and certain other polyanionic pharmaceuticals, featuring predominantly heparin-dependent antibodies), autoimmune HIT (aHIT; severe subtype of HIT that features both heparin-dependent and heparin-independent platelet-activating antibodies), and spontaneous HIT (non-heparin triggers such as knee replacement surgery and infection; predominantly heparin-independent platelet-activating antibodies). Most recently, a novel fourth anti-PF4 disorder, vaccine-induced immune thrombotic thrombocytopenia (VITT), was identified as an ultrarare complication of adenovirus vector vaccines. VITT is characterized by thrombocytopenia, disseminated intravascular coagulation, a high frequency of thrombosis-including in unusual sites (cerebral veins, splanchnic veins)-and highly pathogenic anti-PF4 antibodies with heparin-independent platelet-activating properties.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Review · Consensus signal: Review
Teacher disagreement score0.978
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0060.001
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0010.002
Insufficient payload (model declined to judge)0.0030.000

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.

Opus teacher head0.164
GPT teacher head0.421
Teacher spread0.258 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it