To determine whether our findings were specific to the FcγRIIB−/−Yaa model or were more generally relevant, we measured changes in IRF5 expression in GC B cells, plasmablasts, and plasma cells in 2 additional mouse lupus models, (NZBxNZW)F1 and MRL-lpr. The gene discussed is FCGR2B; the disease is systemic lupus erythematosus.