Pleural infection is a severe and complicated disease which is associated with significant morbidity and mortality. People with pleural infection show diverse levels of neutrophil degranulation activity. The investigators examined the biological role of pleural fluid neutrophil extracellular traps in patients with pleural infection. TORPIDS-3 is an observational, International multicohort study.

Inclusion Criteria:

Patients were included if they had a clinical presentation consistent with pleural infection as stated in the Methods section of the main manuscript and any of the following criteria:

1. Pleural fluid that was macroscopically purulent, OR
2. Pleural fluid that was positive on culture for bacterial infection, OR
3. Pleural fluid that demonstrated bacteria on Gram staining, OR
4. Pleural fluid with pH ≤7.2 (measured in a blood gas analyser) or low glucose level (≤3mmol/L or ≤55mg/dL) in a patient with clinical evidence of infection, OR
5. Contrast-enhanced CT evidence of pleural infection (consolidation of underlying lung with enhancing pleural collection) in a patient with clinical evidence of infection, alongside exclusion of other sources of infection.

Exclusion criteria:

1. Age less than 18 years, OR
2. No pleural fluid available for analysis, OR
3. Patient previous pneumonectomy on the side of pleural infection, OR
4. Expected survival less than three months due to co-morbid disease, as judged by the recruiting physician

Patients with confirmed pleural infection