PT - JOURNAL ARTICLE AU - Gunnar Antoni AU - Mark Lubberink AU - Jens Sörensen AU - Elin Lindström AU - Mathias Elgland AU - Olof Eriksson AU - Michael Hultström AU - Robert Frithiof AU - Anders Wanhainen AU - Jonathan Sigfridsson AU - Paul Skorup AU - Miklos Lipcsey TI - In Vivo Visualization and Quantification of Neutrophil Elastase in Lungs of COVID-19 Patients – A First-In-Human Positron Emission Tomography Study with <sup>11</sup>C-GW457427 AID - 10.2967/jnumed.122.263974 DP - 2022 Jun 01 TA - Journal of Nuclear Medicine PG - jnumed.122.263974 4099 - http://jnm.snmjournals.org/content/early/2022/06/09/jnumed.122.263974.short 4100 - http://jnm.snmjournals.org/content/early/2022/06/09/jnumed.122.263974.full AB - COVID-19 can cause life-threatening lung-inflammation that is suggested to be mediated by neutrophils, whose effector mechanisms in COVID-19 is inexplicit. The aim of the present work is to evaluate a novel PET tracer for neutrophil elastase in COVID-19 patients and healthy controls. METHODS: In this open-label, First-In-Man study, four patients with hypoxia due to COVID-19 and two healthy controls were investigated with positron emission tomography (PET) using the new selective and specific neutrophil elastase PET-tracer [11C]GW457427 and [15O]water for the visualization and quantification of NE and perfusion in the lungs, respectively. RESULTS: [11C]GW457427 accumulated selectively in lung areas with ground-glass opacities on computed tomography characteristic of COVID-19 suggesting high levels on NE in these areas. In the same areas perfusion was severely reduced in comparison to healthy lung tissue as measured with [15O]water. CONCLUSION: The data suggests that NE may be responsible for the severe lung inflammation in COVID-19 patients and that inhibition of NE could potentially reduce the acute inflammatory process and improve the condition.