Comparison of select plasma cytokine levels between COVID-19 ARDS and non–COVID-19 ARDS cohorts. Log-transformed plasma levels of (A) IL-6 (pg/ml), (B) IL-8 (pg/ml), and (C) IL-10 (pg/ml) at early (0–4 d), middle (5–10 d), and late (>10 d) time intervals after intubation in patients with COVID-19 ARDS (n = 27 patients) quantified by multiplex assay compared with historical cohorts including ARDS due to viral pneumonia (n = 14 patients), bacterial pneumonia (n = 21 patients), and culture-negative etiology (n = 30 patients) quantified by prior multiplex assay. Statistical analysis was by Kruskal-Wallis test with Benjamini-Hochberg post hoc test for multiple comparisons of historical groups in relation to the COVID-19 group; asterisks represent post hoc statistical relationships. *P < 0.05, **P < 0.01, and ****P < 0.0001. ARDS = acute respiratory distress syndrome; COVID-19 = coronavirus disease; IL = interleukin.