- severe allergies or allergies after 1st injection to stem cell preparations and their components - patients with a malignant tumor, other serious systemic diseases, and psychosis - co-infection of hiv, tuberculosis, influenza virus, adenovirus, and other respiratory infection viruses - patients with a previous history of pulmonary embolism - be thought by researchers to be inappropriate to participate in this clinical study (expected deaths within 48 hours, uncontrolled infections) - liver or kidney sofa score of more than 3 points; combined with other organ failures (need organ support), stage 4 severe chronic kidney disease or requiring dialysis (i.e. estimated glomerular filtration rate (egfr) < 30) - pulmonary obstructive pneumonia, severe pulmonary interstitial fibrosis, alveolar proteinosis, allergic alveolitis, and other known viral pneumonia or bacterial pneumonia - continuous use of immunosuppressive agents or organ transplants in the past 6 months - in vitro life support (ecmo, ecco2r, rrt) - pregnant or lactating women - uncontrolled underlying disease

- severe allergies or allergies after 1st injection to stem cell preparations and their components - patients with a malignant tumor, other serious systemic diseases, and psychosis - co-infection of hiv, tuberculosis, influenza virus, adenovirus, and other respiratory infection viruses - patients with a previous history of pulmonary embolism - be thought by researchers to be inappropriate to participate in this clinical study (expected deaths within 48 hours, uncontrolled infections) - liver or kidney sofa score of more than 3 points; combined with other organ failures (need organ support), stage 4 severe chronic kidney disease or requiring dialysis (i.e. estimated glomerular filtration rate (egfr) < 30) - pulmonary obstructive pneumonia, severe pulmonary interstitial fibrosis, alveolar proteinosis, allergic alveolitis, and other known viral pneumonia or bacterial pneumonia - continuous use of immunosuppressive agents or organ transplants in the past 6 months - in vitro life support (ecmo, ecco2r, rrt) - pregnant or lactating women - uncontrolled underlying disease