MSC-based Therapy in COVID-19-associated Acute Respiratory Distress Syndrome

Inclusion Criteria: * Clinical diagnosis of COVID-19 confirmed by RT-PCR; * Thorax CT image suggestive of viral pneumonia; * Respiratory failure (SaO2 \<93% with O2 at 5L / min) * Tracheal intubation (first 48 h); Exclusion Criteria: * Pregnancy or breastfeeding; * Patients with a history of cancer, chemotherapy in the past 2 years; * Life expectancy less than 6 months or in exclusive palliative care; * Severe liver failure, with Child-Pugh score\> 12; * High probability of death in the following 48 h; * Previous renal failure: patients who were already on dialysis or patients with RFG \<30ml / min / 1.73 m2; * Clinical or radiological suspicion of tuberculosis and bacterial pneumonia.