Covid: Trigger of rare blood clots with AstraZeneca jab found by scientists

[Treeman]

"Scientists believe they have found "the trigger" that leads to extremely rare blood clots after the Oxford-AstraZeneca Covid vaccine.

People with clots had unusual antibodies that were attacking a protein in their blood called platelet factor four"

Covid: Trigger of rare blood clots with AstraZeneca jab found by scientists - BBC News

 

[BrightCandle]

Prof Alan Parker, one of the researchers at Cardiff University, told BBC News: "The adenovirus has an extremely negative surface, and platelet factor four is extremely positive and the two things fit together quite well."
He added: "We've been able to prove the link between the key smoking guns of adenoviruses and platelet factor four.

They are admitting to 73 deaths from vaccine-induced immune thrombotic thrombocytopenia due to AZ.

 

[SWAlexander]

I´m not sure if it is only AstraZeneca. I had BioNtech/Pfizer vaccine and blood clots.

 

[Pyrrhus]

I´m not sure if it is only AstraZeneca. I had BioNtech/Pfizer vaccine and blood clots.

The particular mechanism that they are describing only applies to adenovirus-vector vaccines such as AstraZeneca or Johnson&Johnson:

ChAdOx1 interacts with CAR and PF4 with implications for thrombosis with thrombocytopenia syndrome (Baker et al., 2021)
https://www.science.org/doi/10.1126/sciadv.abl8213

Excerpt:

Vaccines derived from chimpanzee adenovirus Y25 (ChAdOx1), human adenovirus type 26 (HAdV-D26), and human adenovirus type 5 (HAdV-C5) are critical in combatting the severe acute respiratory coronavirus 2 (SARS-CoV-2) pandemic. As part of the largest vaccination campaign in history, ultrarare side effects not seen in phase 3 trials, including thrombosis with thrombocytopenia syndrome (TTS), a rare condition resembling heparin-induced thrombocytopenia (HIT), have been observed.

This study demonstrates that all three adenoviruses deployed as vaccination vectors versus SARS-CoV-2 bind to platelet factor 4 (PF4), a protein implicated in the pathogenesis of HIT. We have determined the structure of the ChAdOx1 viral vector and used it in state-of-the-art computational simulations to demonstrate an electrostatic interaction mechanism with PF4, which was confirmed experimentally by surface plasmon resonance.

These data confirm that PF4 is capable of forming stable complexes with clinically relevant adenoviruses, an important step in unraveling the mechanisms underlying TTS.

 

[SWAlexander]

The particular mechanism that they are describing only applies to adenovirus-vector vaccines such as AstraZeneca or Johnson&Johnson:
Thanks Pyrrhus
Just got this (again)

Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination

Conclusions
Vaccination with ChAdOx1 nCov-19 can result in the rare development of immune thrombotic thrombocytopenia mediated by platelet-activating antibodies against PF4, which clinically mimics autoimmune heparin-induced thrombocytopenia. (Funded by the German Research Foundation.)
https://www.nejm.org/doi/full/10.1056/NEJMoa2104840

 

[andyguitar]

People with clots had unusual antibodies that were attacking a protein in their blood called platelet factor four"

I wonder if these antibodies are also present in Long Covid patients.

 

[Alvin2]

ChAdOx1 interacts with CAR and PF4 with implications for thrombosis with thrombocytopenia syndrome (Baker et al., 2021)
https://www.science.org/doi/10.1126/sciadv.abl8213

state-of-the-art computational simulations

I find this interesting

 

[SNT Gatchaman]

Would be good to see if it is present in the micro-clots found in LC, following platelet hyperactivation.

From Wikipedia:
Platelet factor 4 (PF4) is a small cytokine belonging to the CXC chemokine family that is also known as chemokine (C-X-C motif) ligand 4 (CXCL4) . This chemokine is released from alpha-granules of activated platelets during platelet aggregation, and promotes blood coagulation by moderating the effects of heparin-like molecules. Due to these roles, it is predicted to play a role in wound repairand inflammation. It is usually found in a complex with proteoglycan.

Platelet factor-4 is a 70-amino acid protein that is released from the alpha-granules of activated platelets and binds with high affinity to heparin. Its major physiologic role appears to be neutralization of heparin-like molecules on the endothelial surface of blood vessels, thereby inhibiting local antithrombin activity and promoting coagulation. As a strong chemoattractant for neutrophils and fibroblasts, PF4 probably has a role in inflammation and wound repair.