Platelet-derived sCD40L: specific inflammatory marker for early-stage severe acute respiratory syndrome coronavirus 2 infection

Background The SARS-CoV-2 virus is the causing agent of the Coronavirus disease 2019 (COVID-19) characterized by a huge pro-inflammatory response and coagulation disorders that may lead to for its severe forms, in organ failure or even death. As major players of thrombo-inflammation, platelets release large amounts of immunomodulatory molecules and regulate leukocyte and endothelial activity, which are both altered in COVID-19. Altogether, this makes platelets a very likely actor of the thrombo-inflammatory complications of COVID-19. Thus, we propose to identify a platelet inflammatory signature of severe COVID-19 specifically modulated throughout the course of the disease. Methods Luminex technology and enzyme-linked immunosorbent assay were used to assess plasma levels of platelet inflammatory markers in patients with severe acute respiratory syndrome coronavirus 2 infection on admission and for 14 days afterwards. Results In accordance with the observations of other teams, we evidence that the plasma levels of the platelet soluble (s)CD40L is significantly elevated in the early stages of the disease. Interestingly we observe that the plasma level of sCD40L decreases overtime while that of sCD62P increases significantly. Conclusions Our data suggest that there is a platelet signature of inflammatory response to SARS-COv-2 infection which varies overtime and could serve as monitoring biomarkers of patient inflammatory state. Clinical trial registration number: 2020-A01100-39; title: Human Ab Response & immunoMONItoring of COVID-19 Patients, registration date: 05/25/2020; URL of the registry: https://clinicaltrials.gov/ct2/history/NCT04373200?V_5=View.