IRF5 and Autoimmunity: Consistent with a contribution of IRF5 to autoimmunity, and a contribution of lupus-like inflammation to IRF5 expression, the autoimmune C57BL/6.Nba2, NZB/W, and Sle123 mouse strains all exhibit increased expression of IRF5 in splenic cells compared with C57BL/6 mice (20).