Fig. 2

Changes in IL-6 and the PaO2/FiO2 ratio in patients with COVID-19 with/without UC-MSCs transfusion on day 0, 3, and 7. The changes in IL-6 and the PaO2/FiO2 ratio were recorded at day 0, 3, and 7 after UC-MSCs treatment. a The changes in serum IL-6 levels in the patients receiving UC-MSCs treatment. b The changes in the PaO2/FiO2 ratio in patients with severe disease receiving UC-MSCs treatment. c The changes in IL-6 levels in the control group. d The changes in the PaO2/FiO2 ratio in patients with severe disease in the control group