In this study, the effects of whole-body irradiation on SLE-like morbidity in NZBWF1 mice were investigated based on renal lesion development, urinary protein levels, anti-dsDNA antibody production, and lifespan were evaluated to determine whether whole-body irradiation could ameliorate SLE-like morbidity and how CD180-negative cells could contribute for this process in vivo. This evidence concerns the gene CD180 and systemic lupus erythematosus.