How Some Vaccines Induce Thrombocytopenia and Thrombosis

Clinical Takeaway

: A genetic predisposition and a somatic mutation result in antibodies that recognize both the adenovirus core protein VII and platelet factor 4.

Context

Vaccine-induced thrombosis with thrombocytopenia (VITT) is a rare, yet severe, adverse effect of adenovirus-vectored Covid-19 vaccines. The same reaction can occur rarely following adenoviral infection. Platelet-activating antibodies targeting the platelet factor 4 (PF4) trigger VITT, but the adenoviral antigen that initiates this aberrant response was unknown. To answer this question, investigators applied genomic and proteomic profiling to samples from 21 patients with VITT (or pre-VITT) after adenovirus-vectored Covid-19 vaccines.

Key Results

Antibodies are composed of heavy and light chains, and all antibodies from VITT patients had similar molecular fingerprints (specific determinants in the light chain) that suggested a genetic p…

Reviewing Author

Hana M. El Sahly, M.D.

Disclosures

Grant/Research SupportNational Institutes of Health