IL15 and systemic lupus erythematosus: IL-15 increased the percentages of NK cells in SLE patients with inactive disease (4.9 ± 0.6% vs. 3.5 ± 0.5%, p = 0.001), but not SLE patients with active disease (5.9 ± 0.5% vs. 5.6 ± 0.6, p = 0.104).