Shared transcriptional profiles at the single cell level of atypical memory B cells suggest common drivers of expansion and function in malaria, HIV and autoimmune diseases [HIV scRNA-seq]

Human chronic infectious diseases, including malaria and HIV and autoimmune diseases, notably SLE, are accompanied by a striking expansion of a subpopulation of B cells termed atypical memory B cells (MBCs). We compared the single cell transcriptional profiles of B cells in malaria and HIV, characterizing and uncovering heterogeneity within each B cell subset. Remarkably, atypical MBC clusters in these two diseases showed significant similarities to each other as well as to atypical MBCs in autoimmune diseases, suggesting a common driver of their expansion and shared functions. Focusing on atypical MBCs in malaria we identified an IgD+IgMlo subpopulation that expanded in children upon the onset of febrile malaria, showed a distinct V gene usage characteristic of antigen-driven B cell populations and unexpectedly, had acquired high antigen-affinity thresholds for activation. We speculate that in malaria IgD+IgMlo atypical MBCs expand to limit responses to low-affinity self-antigens, a function that may be shared by atypical MBCs in other chronic infections and autoimmune diseases. scRNA seq of peripheral blood B cells isolated by negative selection from three HIV-infected adults and three healthy adults, all from the US The raw data is to be made available through dbGaP (controlled access; phsnnnnnn)