CD19 and systemic lupus erythematosus: Human: Increased CD19+CD27- naïve B cells, decreased CD19+CD27+ memory cells, decreased CD27hi plasma cells, and decreased CD27-IgD-CD11c+T-bet+ DN2 cells compared to SLE B cellsMouse: Reduced germinal center B cells, plasma cells, and ABCs (murine equivalent of DN2 cells) compared to lupus B cells