IL15 and systemic lupus erythematosus: However, the combination of IL-15 and α-GalCer resulted in greater increase of the percentages of iNKT cells compared to α-GalCer alone in controls (14.0±2.7% vs 5.5±1.4%, p = 0.016) and SLE patients as well (2.0±0.5% vs 0.8±0.2%, p = 0.008).