[Method and impact of allografts cryopreservation during the Covid-19 pandemic: guidelines from the SFGM-TC].

The COVID-19 pandemic disorganized the allogeneic stem cell transplantation activities all over the world, with the necessity to cryopreserve allografts to secure the procedure for both the recipient and the donor. Cryopreservation, usually anecdotal, has been used by all the French speaking centers; data collected from 24 centers were assessed in order to determine the impact of cryopreservation on the quality of allografts. Our analysis clearly demonstrates that increasing transit time (more than 48hours) is deleterious for CD34 recovery, legitimates the slight increase of the requested CD34 cell dose with respect to the average recovery rate as well as the importance of the quality control on the infused product.