Consistent with our results, increases in hyaluronan were also confirmed in severe or critical patients with COVID-19.23 Notably, hyaluronan is accumulated in the bronchoalveolar lavage fluid (BALF) and serum samples of patients with ARDS.24 We also found that hyaluronan was significantly correlated with lymphocytes, CRP, D-dimer, and fibrinogen. This evidence concerns the gene CRP and acute respiratory distress syndrome.