Pathogen-specific host responses define distinct pneumonia endotypes in the human lung

Area of Science:

• Pulmonary Medicine
• Infectious Diseases
• Immunology

Background:

• Pneumonia is a leading infectious cause of death globally.
• Current diagnosis relies on syndromic definitions, lacking molecular resolution and ignoring endotypes.
• There's a need for advanced diagnostic and treatment strategies for pneumonia.

Purpose of the Study:

• To test if pathogen-specific host responses in the alveolar space define distinct pneumonia endotypes.
• To link these endotypes to specific clinical features and patient outcomes.
• To explore individualized therapeutic strategies for pneumonia.

Main Methods:

• Prospective enrollment of 690 patients with suspected or confirmed pneumonia requiring mechanical ventilation.
• Analysis of 792 bronchoalveolar lavage (BAL) fluid samples using flow cytometry and single-cell RNA-sequencing.
• Machine learning models applied to transcriptomic data and clinical records to identify host-pathogen interactions.

Main Results:

• Identification of pathogen-specific host responses in alveolar immune cells via transcriptomics.
• Association of these responses with distinct alveolar cell abundance and clinical features.
• Discovery of distinct pneumonia endotypes linked to clinical presentation and outcomes.

Conclusions:

• Dynamic, pathogen-specific host responses define distinct pneumonia endotypes.
• These endotypes correlate with clinical features and outcomes.
• Individualized therapeutic strategies targeting specific host-pathogen interactions are recommended for pneumonia treatment.