RESUMEN
Key Findings@#There is some short-term benefit from the use of mesenchymal stem cell therapy for severe COVID-19 in a lowquality, small randomized controlled trial (RCT). Further studies, ideally with good quality RCTs, are needed to confirm benefit and safety. • Mesenchymal stem cells (MSCs) are non-hematopoietic adult stem cells that are able to self-renew and differentiate into various cells of any cell lineage. MSCs have the ability to migrate (homing) to damaged tissue for repair and regeneration, as well as signal other cells to help in tissue repair. It can effect cellular differentiation, consequently shifting the immune system from Th1 to Th2 responses.1,2 • A recent review showed improved disease-associated parameters in experimental acute respiratory distress syndrome (ARDS).3 • We found three studies (one case report, one prospective cohort, and one small randomized controlled trial) reporting the effects of MSC on COVID-19. Based on low-quality evidence, it appeared that human umbilical cord blood-derived MSC, given after failure to improve with standard treatment, had beneficial effects in terms of earlier onset of clinical improvement among individuals with severe or critical COVID-19. However, 28-day clinical improvement and mortality were not significantly different compared to standard treatment. There was no reported adverse reaction. • There are 52 registered and ongoing clinical trials to investigate the efficacy and safety of mesenchymal stem cells as treatment for COVID-19. • Mesenchymal stem cell therapy is not included in any of the existing guidelines for the treatment of COVID-19.