Case Report: Hypergranular Platelets in Vaccine-Induced Thrombotic Thrombocytopenia After ChAdOx1 nCov-19 Vaccination

• DOI: 10.3389/fcvm.2022.824601
• Publication Date: 2022-02-09T15:04:58Z
• Authors: Shane P. Comer; Ana Le Chevillier; Paulina B. Szklanna; Sarah Kelliher; Khalid Saeed; Steven Cullen; Osasere Edebiri; Tiina O'Neill; Niamh Stephens; Luisa Weiss; Claire A. Murphy; Saraswathi Rajakumar; Alexandra Tierney; Conor Hughes; Áine Lennon; Niamh Moran; Patricia B. Maguire; Fionnuala Ní Áinle; Barry Kevane
• Keywords: 2019-20 coronavirus outbreak

Vaccine-induced thrombotic thrombocytopenia (VITT) post SARS-CoV-2 vaccination is characterized by and severe thrombosis. Platelet function during patient recovery in the medium-/long-term has not been investigated fully. Here, we undertook a 3-month study, assessing of VITT platelet morphology, granule content dense-granule release at two distinct time points recovery. A 61 year-old female was admitted to hospital 15 days ChAdOx1 nCov-19 vaccination. Hematological parameters peripheral blood smears were monitored over 3 months. morphology populations assessed using transmission electron microscopy (TEM) recovery, as agonist-induced release. Upon admission, had reduced counts, increased D-dimer high anti-PF4 antibodies with multiple sites cerebral venous sinus thrombosis (CVST). Peripheral revealed presence large, hypergranular platelets. Following treatment, hematological returned normal ranges study period. Anti-PF4 remained persistently up 90 post-admission. Two after platelets contained more granules per-platelet when compared day 72 healthy Additionally, maximal ATP (marker release) on 2 control This highlights previously unreported observation hypergranularity which may contribute risk associated VITT. Optimal approaches monitoring from remains be determined but our findings help inform therapeutic decisions relating anticoagulation treatment this novel pathology.