CXCL8 and acute respiratory distress syndrome: Lung injury score, oxygenation index, and serum levels of immuno- and angiomodulatory cytokines (IL-1, IL-6, IL-8, TNF-α, IL-10, and TGF-β) will be determined to evaluate therapeutic effects of WJ-MSCs in attenuation of SARS-CoV-2-induced ARDS.