Comparative analysis of compartment-specific immunothrombotic biomarker profiles in bronchoalveolar lavage fluid and serum of patients with pneumonia-related acute respiratory distress syndrome: A preliminary cross-sectional study

Immunothrombosis has emerged as a potential mechanistic link underlying the development and progression of acute respiratory distress syndrome (ARDS), but understanding its specific profile in patients, both locally and systemically, is limited. The objective of this study was to characterize and compare the immunothrombotic signatures in patients diagnosed with pneumonia-related ARDS (p-ARDS) at both the pulmonary and systemic levels and to evaluate their clinical relevance. The study included 23 consecutive patients diagnosed with p-ARDS admitted to the intensive care unit at a tertiary university hospital from July 2022 to May 2023, alongside 40 concurrently hospitalized patients with common pneumonia as controls. Paired bronchoalveolar lavage fluid (BALF) and serum samples were collected from the participants for the analysis of 15 biomarkers to assess and quantify the pulmonary and systemic immunothrombotic signatures. The study results revealed significant pulmonary inflammation and systemic endothelial injury in p-ARDS patients compared to pneumonia controls. These observations were maintained after adjustment for severity of illness (Acute Physiology and Chronic Health Evaluation II scores). In terms of clinical relevance, inflammatory biomarkers (interleukin [IL]-6, IL-8) in BALF were found to correlate with PaO₂/FiO₂ ratio, while serum levels of a disintegrin and metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS-13) and thrombomodulin showed associations with Sequential Organ Failure Assessment and Disseminated Intravascular Coagulation scores. In conclusion, this preliminary investigation identified compartment-specific variations in the immunothrombotic signature between patients with p-ARDS and those with pneumonia alone, with inflammatory responses predominantly localized in the alveolar compartments and coagulation/endothelial injury biomarkers more pronounced in peripheral blood.