Yang et al. demonstrated that a brief treatment with α-GalCer in 7-week-old BWF1 mice suppressed lupus nephritis20. On the other hand, Zeng et al. reported contradictory results, namely that multiple injections of α-GalCer in 20-week-old BWF1 mice exacerbated lupus nephritis19. Regarding this point, a complex role for NKT cells in SLE, that is, a potential protective role before the onset of the disease and a potential pathogenic role after the establishment of the disease has been proposed16. Moreover, the age of the mice and the α-GalCer dose or administration interval may have influenced these conflicting results. However, we considered that the administration of α-GalCer to young mice was clinically unsuitable, because current international guidelines do not recommend the treatment of patients with mild lupus nephritis using immunosuppressive therapies38. We, therefore, began the α-GalCer treatment at 24 weeks of age, when mice may already develop mild renal disease.