BCR and COVID-19: In this study, we used a single-cell approach to look at the dynamic changes in the transcriptomic BCR repertoire in patients with COVID-19 at various stages, comparing a recovered and a deceased COVID-19 patient who had been supported with ECMO with one COVID-19-recovered patient who had not received ECMO treatment and one healthy subject who had never previously been infected nor tested positive for SARS-CoV-2 antibodies.