In an analysis of B cell changes in relation to renal flare development within the same SLE population from trials of belimumab (unpublished data), patients who developed renal flares showed a more prominent rapid decrease in CD19+CD20+CD138+ short-lived plasma cells and CD19+CD20−CD27bright plasmablasts compared with patients who did not flare, followed by a subsequent return. Here, CD19 is linked to systemic lupus erythematosus.