While PLD4 + B cells were expanded in nearly all our patients with SLE irrespective of disease states, further analysis allowed us to define “PLD4 + blast” as a unique subset within PLD4 + B cells, which in contrast were expanded in parallel with disease activity and the expansion of plasmablasts and highly overlapped with DN2 cells. This evidence concerns the gene PLD4 and systemic lupus erythematosus.