LAUSR

Mesenchymal Stromal Cells (MSCs) are under active consideration as a treatment strategy to control the hyperinflammation and slow disease progression in COVID-19. The possible mechanism of protection through their immunoregulatory and paracrine action has been reviewed extensively. However, the importance of process control to achieve a consistent cell quality, maximum safety and efficacy - for which the three key questions are of ‘which’, ‘when’ and ‘how much’ - remain unaddressed. Any commonality, if exists, in the ongoing clinical trials is yet to be analysed and reviewed. In this review, we have therefore compiled and discussed study design data from ongoing clinical trials to address the key questions of ‘which’ tissue source, donor profile, isolation technique, culture conditions, long-term culture and cryopreservation for MSCs; the question of ‘when’ with regard to defining the transplantation window, by identifying and staging of patients based on their pro-inflammatory profile; and finally that of ‘how much’ with respect to the number of cells in a single administration, the number of doses and route of transplantation. To homogenize MSC therapy for COVID-19 on a global scale and to make it readily available in large numbers, a shared understanding and uniform agreement on these fundamental issues is essential.