CD19 and systemic lupus erythematosus: Within a pooled cohort of 1712 patients with SLE, treatment responders showed more prominent decreases from baseline through week 52 in CD19+CD20+CD27− naïve B cells, CD19+CD20−CD27bright plasmablasts, and CD19+CD20−CD138+ long-lived plasma cells, and a more prominent rapid (through week 8) and early (through week 24) expansion of CD19+CD20+CD27+ memory B cells compared with non-responders (116).