Bone Marrow-Derived Mesenchymal Stem Cell Treatment for Severe Patients With Coronavirus Disease 2019 (COVID-19)

COVID-19 has become a urgent and serious public health event that threatens human life and health globally. No specific pharmacological treatments are available to date for COVID-19.Patients contracting the severe form of the disease constitute approximately 15% of the cases which is characterized by extensive acute inflammation. In these severe cases, there will be rapid respiratory system failure. MSCs have been employed extensively in cell therapy, which includes a plethora of preclinical research investigations as well as a significant number of clinical trials. Safety and efficacy have been shown in many clinical trials. Previous studies have shown that MSCs could significantly reduce inflammatory cell infiltration in lung tissue, reduce inflammation in lung tissue, and significantly improve lung The structure and function of tissues protect lung tissue from damage.The mechanisms underlying the improvements after MSC infusion in COVID-19 patients also appeared to be the robust antiinflammatory activity of MSCs. Recent studies also showed that intravenous MSC infusion could reduce the overactivation of the immune system and support repair by modulating the lung microenvironment after SARS-CoV-2 infection. MSC therapy inhibiting the overactivation of the immune system and promoting endogenous repair by improving the lung microenvironment after the SARS-CoV-2 infection. The purpose of this study is to investigate the safety and efficacy of intravenous infusion of mesenchymal stem cells in severe patients With COVID-19.The respiratory function, pulmonary inflammation, clinical symptoms, pulmonary imaging, side effects, immunological characteristics will be evaluated.