Clonal expansion and activation of tissue-resident memory-like Th17 cells expressing GM-CSF in the lungs of severe COVID-19 patients.


Yu Zhao, Christoph Kilian, Jan-Eric Turner, Lidia Bosurgi, Kevin Roedl, Patricia Bartsch, Ann-Christin Gnirck, Filippo Cortesi, Christoph Schultheiß, Malte Hellmig, Leon U B Enk, Fabian Hausmann, Alina Borchers, Milagros N Wong, Hans-Joachim Paust, Francesco Siracusa, Nicola Scheibel, Marissa Herrmann, Elisa Rosati, Petra Bacher, Dominik Kylies, Dominik Jarczak, Marc Lütgehetmann, Susanne Pfefferle, Stefan Steurer, Julian Schulze Zur-Wiesch, Victor G Puelles, Jan-Peter Sperhake, Marylyn M Addo, Ansgar W Lohse, Mascha Binder, Samuel Huber, Tobias B Huber, Stefan Kluge, Stefan Bonn, Ulf Panzer, Nicola Gagliani, Christian F Krebs

Year of publication



Sci Immunol







Impact factor



Hyperinflammation contributes to lung injury and subsequent acute respiratory distress syndrome (ARDS) with high mortality in patients with severe coronavirus disease 2019 (COVID-19). To understand the underlying mechanisms involved in lung pathology, we investigated the role of the lung-specific immune response. We profiled immune cells in bronchoalveolar lavage fluid and blood collected from COVID-19 patients with severe disease and bacterial pneumonia patients not associated with viral infection. By tracking T cell clones across tissues, we identified clonally expanded tissue-resident memory-like Th17 cells (Trm17 cells) in the lungs even after viral clearance. These Trm17 cells were characterized by a a potentially pathogenic cytokine expression profile of IL17A and CSF2 (GM-CSF). Interactome analysis suggests that Trm17 cells can interact with lung macrophages and cytotoxic CD8+ T cells, which have been associated with disease severity and lung damage. High IL-17A and GM-CSF protein levels in the serum of COVID-19 patients were associated with a more severe clinical course. Collectively, our study suggests that pulmonary Trm17 cells are one potential orchestrator of the hyperinflammation in severe COVID-19.