BALF single-cell landscape in CARDS and non-ARDS patients at two time points

In this study, single-cell sequencing of the BALF of CARDS patients yielded the following results: (1) IL1B+ neutrophils were significantly increased in the BALF of CARDS patients with exacerbated disease, which was associated with poor prognosis of CARDS patients, and this type of neutrophils underwent fatty acid metabolism reprogramming in comparison with other types of neutrophils, which may be related to their high-inflammatory response. (2) IL1B+ neutrophils promoted TNF secretion from hyperinflammatory type M1 macrophages through a caspase-dependent pathway, suggesting that neutrophil-macrophage interactions play an important role in the mechanism of CARDS development. A total of 8 patients with severe ARDS, including 4 CARDS patients and 4 non-CARDS patients (2 bacterial pneumonia, 2 fungal pneumonia), were included in this study, of which 2 patients were treated with ECMO, and the rest of the patients received hormone therapy except for 1 patient who did not receive hormone therapy. BALF was retained in each patient at the time point of admission to the ICU (t1) and at the time point of development of an MS change value ≥1 point (t2).