HMGB1 and acute respiratory distress syndrome: HMGB1 levels between ARDS with and without COVID-19 were not significantly different (p = 0.25), with a median of 19.6 μg/L (IQR, 10.0 to 30.3) and 33.6 μg/L (IQR, 23.3 to 62.4), respectively (Fig 2).