In Vivo Visualization and Quantification of Neutrophil Elastase in Lungs of COVID-19 Patients: A First-in-Humans PET Study with<sup>11</sup>C-NES
Gunnar Antoni, Mark Lubberink, Jens Nørkær Sørensen, Elin Lindström, Mathias Elgland, Olof Eriksson, Michael Hultström, Robert Frithiof, Anders Wanhainen, Jonathan Sigfridsson, Paul Skorup, Miklós Lipcsey
Abstract
Coronavirus disease 2019 (COVID-19) can cause life-threatening lung inflammation that is thought to be mediated by neutrophils. The aim of the present work was to evaluate a novel PET tracer for neutrophil elastase (NE). <b>Methods:</b> In this first-in-humans study, 4 patients with hypoxia due to COVID-19 and 2 healthy controls were investigated with PET using <sup>11</sup>C-NES and <sup>15</sup>O-water for visualization and quantification of NE and perfusion in the lungs, respectively. <b>Results:</b><sup>11</sup>C-NES accumulated selectively in lung areas with COVID-19 opacities on CT scans, suggesting high levels of NE there. In the same areas, perfusion was severely reduced in comparison to healthy lung tissue as measured with <sup>15</sup>O-water. <b>Conclusion:</b> The data suggest that NE is associated with severe lung inflammation in COVID-19 patients and that inhibition of NE could potentially reduce the acute inflammatory process and improve the condition.