IFNG and systemic lupus erythematosus: IL-15 enhanced IFN-γ production of α-GalCer treated iNKT cells from SLE patients (91.2±1.7% vs. 69.8±3.9%, p<0.001) as well as controls (86.5±3.8% vs. 73.2±4.7%, p = 0.003) (Fig 6B).