Lung compartmentalization of inflammatory biomarkers in COVID-19-related ARDS

Excerpt

We read with great interest the article of Bendib et al. published in Critical Care [1], in which they systematically assessed inflammatory mediators in pneumonia-related ARDS, both in airways and blood compartments. The authors observed a lung compartmentalization of inflammatory mediators, with important heterogeneity in the bronchoalveolar lavage fluid-to-serum concentration ratios across the mediators screened. The concept of compartmentalization of inflammation has already been formulated in pneumonia [2], and issues raised by assessing lung inflammation using blood inflammatory markers has also been highlighted, as well as the subsequent limitations of these biomarkers for bedside management [3]. However, we believe that it is critical to examine it further in ARDS, in this COVID-19 era. Indeed, since the beginning of the pandemic, most of the studies exploring immune dysregulation during COVID-19 were nevertheless based on data obtained only from blood, not because this is the most relevant compartment, but because it is the most easily accessible. …