PB0868 - Detection of hyperfunctioning platelets and novel phenotypic platelet subtypes

Background: Platelets are important mediators in maintaining homeostasis and in pathology of bleeding and thrombosis. In addition, they are now known to be highly heterogeneous in phenotype markers such as size, density and receptor content as well as their function with both highly reactive platelets as well as hard to activate platelet subtypes. However, while many clinical methods exist to detect hypofunctioning platelets, methodology for the detection of hyperfunctioning platelets is lacking and limited to high-on-treatment response detection when treated with anti-platelet agents.

Aims: We aim to design a highly polychromatic flow cytometry panel to detect platelet subtypes in hyperfunctioning platelets.

Methods: We designed a novel multi-colour flow cytometry panel that utilises modern innovations in flow cytometers and new dyes to map distinct platelet phenotypes in hyperfunctioning platelets. Our ultimate goal is to identify clinically relevant subtypes of platelets that predict thrombosis risk more accurately in individuals with a higher risk due to smoking, obesity and diabetes so that anti-platelet treatment can be tailored to those patients with a clinically relevant high risk. Furthermore, results were analysed using both traditional subsequent gating strategies as well as new unsupervised clustering algorithms such as Principal Component Analysis, t-distributed stochastic neighbour embedding (t-SNE) and Uniform manifold approximation and projection (UMAP).

Results: We designed a 14 colour panel with antibodies against CD9, CD29, CD31, CD32, CD36, CD41, CD42a, CD61, CD62P, CD63, CD107a, CD154, MHC class 1 and PAC-1. This combination of markers has the potential to detect known and novel subtypes of platelets in healthy volunteers and can be used in patient samples in the future.

Conclusion(s): Detecting multiple subtypes of platelets brings clinically relevant hyperfunction of platelets a step closer and can lead us to find specific subtypes to target with anti-platelet treatment in the future.