Vaccine-induced immune thrombotic thrombocytopenia after ChAdOx1 nCoV-19 vaccine in an older patient: Minireview and a case report

Rare cases of unusual thrombosis and thrombocytopenia after administration of the ChAdOx1 nCoV-19 vaccine (AstraZeneca) have been reported. The unusual symptoms are called vaccine-induced immune thrombotic thrombocytopenia (VITT). In the present study, a brief background about cases of unusual thrombosis and thrombocytopenia after administration of the ChAdOx1 nCoV-19 was provided. In addition, a description of a case of a 66-year-old woman who had received this vaccine and developed VITT was done. She presented to the hospital complaining of hematomas in the right upper limb 14 days after the ChAdOx1 nCoV-19 vaccine, without a history of trauma (Glasgow coma scale of 14) and thrombocytopenia even though signs of thrombosis were absent. Cranium computed tomography scan indicated intraparenchymal hematoma and cerebral thrombosis, besides anastomotic Labbé vein thrombosis. The woman received platelets transfusion, dexamethasone, and neuroprotection measures, but even so, on the twelfth postoperative day, she died of cerebral rebleeding. In conclusion, it is crucial to point out the immuno-hypersensitivity mechanisms associated with ChAdOx1 nCoV-19 vaccine reactions, helping to reduce their occurrences and reinforcing confidence in vaccine administration.

Evaluation of a flow cytometric method for simultaneous leukocyte phenotyping and quantification by fluorescent microspheres

We describe a flow cytometric method using a newly designed product, fluorochrome-containing microspheres (Flow Count fluorospheres), which facilitates the precise quantification of cells in whole blood samples or heterogeneous cell suspensions on a single-cell level. These microparticles are easily distinguishable from other events of interest and can be detected by their light-scattering and fluorescence properties. In contrast to the traditional manual or automated cell-counting techniques, this method offers the opportunity to quantify cells simultaneously with flow cytometric immunophenotyping without additional cell loss or other cell preparation steps. We evaluated the accuracy and reproducibility of this flow cytometric method on the determination of CD45+ leukocyte counts and compared the results with those obtained by conventional techniques. Particular interest was focused on the behavior of cells and fluorospheres regarding their sedimentation rate over the period of analysis. The data from 48 blood samples with low, normal, and high leukocyte counts confirmed the reliability and comparability of the flow cytometric method, permitting the determination of white blood cell concentration at least to a limit of 100 cells/microL. A broad field of applications will benefit from this flow cytometric supplement because it is easy to perform and highly accurate. The results appear to be transferable to clinical decision-making monitoring of CD4+ lymphocytes in patients infected with human immunodeficiency virus or of CD34+ hematopoietic cells, optimizing the harvest for peripheral blood stem cell transplantation.