Abstract:
Background: Sepsis-induced acute respiratory distress syndrome (sepsis-induced ARDS) is associated with significant in-hospital mortality. According to current evidence, neutrophil extracellular traps (NETs) mediate alveolar-endothelial damage, leading to acute lung injury. Citrullinated histone H3 (CitH3), which is increased in patients with septic shock, is highly involved in a program for formation of NETs. We aim to differentiate patients with sepsis versus non-sepsis- induced ARDS by using CitH3 in serum and bronchoalveolar lavage (BAL). Methods: Retrospective analysis of prospectively collected samples including clinical data and laboratory characteristics was conducted between June 2021 and February 2022. Intubated patients with ARDS defined by Berlin criteria were enrolled. Levels of CitH3 in both serum and BAL were performed with Enzyme-linked Immunosorbent Assay (ELISA) developed in house. The etiology of ARDS was based on microbiological evidence and primary physicians diagnosis. Results: There was no significant difference of both serum and BAL CitH3 concentration between sepsis-induced ARDS and non-sepsis-induced ARDS patients [median (IQR): serum CitH3 118.4 ng/ml (63.13-215.57) vs 63.3 ng/ml (38.86-89.4), p=0.15; BAL CitH3 61.92 ng/ml (42.22-106.98) vs 41.25 ng/ml (28.19-50.1), p=0.23]. There was positive correlation between levels of CitH3 in serum and BAL (rs =0.77, p =0.005). No correlation was observed between levels of CitH3 in serum and severity of lung injury defined by P:F ratio, APACHE score and SOFA score. Conclusion: This finding suggests that levels of CitH3 in both serum and BAL tend to be higher in the patients with sepsis-induced ARDS. However, the levels did not reach statistical significance. Additionally, serum CitH3 concentration is positively correlated with BAL CitH3 concentration. Data interpretation was limited due to small sample size resulting in reduced power of the study. Future investigations with greater sample size are required to evaluate CitH3 patterns of BAL in the patients with ARDS.