Single cell transcriptomic atlas reveals distinct immune signatures following transfusion of COVID-19 convalescent plasma in severe COVID-19.

The inflammatory responses of severe patients before and after Convalescent COVID-19 plasma (CCP) transfusion are poorly understood. To clarify the immune response and potential pro-inflammatory factors in severe patients after CCP transfusion, we performed single-cell RNA sequencing on peripheral blood mononuclear cells (PBMCs) from severe COVID-19 patients before and 24 h after CCP transfusion. At 24 h after CCP transfusion, T and B cell proportions increased modestly without significant changes in TCR/BCR diversity. Importantly, concurrent upregulation of S100A8 in both CD4 memory T cells and B cells suggests that CCP transfusion may promote an inflammatory response in these cell subsets. Cell communication analysis revealed that CCP transfusion induced selective disruption of NK cell communication with TCR-negative T cells and BCR-positive B cells. Our data suggest CCP transfusion promoted the inflammatory response and interrupt the communication between adaptive immune cells and innate immune cells in severe COVID-19.