Both multiple myeloma (MM) and systemic lupus erythematosus (SLE) are characterized with abnormal production of plasma cells. In both diseases, the process of B cells differentiate into plasmablast/plasma cell is disordered. Despite the continuous research on the development of prognostic factors and introduction of new agents, dysregulation of plasmablast/plasma cells in MM and SLE is still uncontrolled. Thus, it is necessary to explore the novel therapeutic target to plasmablast/plasma cells. We and other researchers have shown that BAFF inhibitor atacicept (TACI-IgG), leads to some degree of B cell depletion. BAFF-specific targeted therapy specifically affects early-stage B cells in the periphery without affecting late-stage compartments such as plasma cells. Specifically depletion of plasma cells could hold great potential for the treatment of autoimmune diseases. To explore the novel therapeutic target to plasma cells, we determined the gene expression profile in B cells (mainly plasma cells) from atacicept (TACI-IgG)-treated lupus-prone MRL/lpr mice by affymetrix microarrays.