Mesenchymal stem cell treatment improves outcomes of COVID-19 patients by multiple immunomodulatory mechanisms

Mesenchymal stem-cell(MSC)infusions into.patients with coronavirus disease 2019 potentially improve clinical symptoms,but the underlying mechanism remains unclear.We conducted a randomized,single-blind,placebo-controlled(29 patients per group)phase II clinical trial to validate previous findings and explore potential mechanisms.Patients treated with umbilical cord derived MSCs had a shorter hospital stay than those receiving the placebo.By day 14,more MSC-group patients entered remission compared with the placebo group.Based on images of the chest,a more severe or critical MSC-group patients showed improvement at day 7 and 21.MSC-group patients had fewer adverse events.