Cytokine-induced memory-like natural killer cells in systemic lupus erythematosus patients

Abstract Background Natural killer (NK) cell abnormalities may contribute to the pathogenesis of systemic lupus erythematosus (SLE). Interleukin (IL)-15, an immunoregulatory cytokine crucial for NK survival, is overexpressed in SLE patients. Cytokine-induced memory-like (CIML) NK cells, which are NK cells pre-activated with short-term IL-12+IL-15+IL-18 followed by incubation with low-dose IL-15 for 1-2 weeks, exhibit enhanced NK effector function upon re-stimulation. Methods We collected blood samples from 54 patients with SLE and 38 healthy volunteers. Extended IL-15 stimulation of peripheral blood mononuclear cells (PBMCs) was performed. Surface marker analysis, IFN-γ, TNF-α production, and cytotoxicity evaluation were conducted. Next, we generated CIML NK cells by culturing PBMCs with IL-12+IL-15+IL-18. The influence of short-term and long-term IL-15 treatment on CIML NK cells was assessed. Finally, we examined the effect of re-stimulation with IL-12+IL-15+IL-18 on CIML NK cells from SLE patients and healthy controls. Cytotoxicity, CD107a degranulation, and surface marker expression were analyzed. Results We found that 1. The percentage of CD3-CD56+ NK cells was initially decreased in SLE patients compared with controls, but was enhanced after long-term IL-15 incubation; 2. Long-term IL-15 stimulation facilitated the conversion from CD3-CD56dim to CD3-CD56bright NK cells; 3. CIML NK cells were successfully generated in SLE patients, showing increased percentages of CD3-CD56+ and CD3- CD56bright NK cells and a concomitant decrease in CD3-CD56dim NK cells; 4. SLE CIML NK cells showed decreased IFN-γ, CD69, CD94, NKG2A, NKG2C, NKP30, NKP44, NKP46, and granzyme B expression compared with healthy controls; 5. On day 8, re-stimulation with IL-12+IL-15+IL-18 further enhanced the expression of IFN-γ, CD69, CD94, NKG2A, perforin, and granzyme B expression on SLE CIML NK cells; 6. Granzyme B expression in SLE CIML NK cells was higher on day 8 than on day 15. Conclusion Our findings revealed phenotypic differences and functional deficiencies in SLE CIML NK cells. Further investigation into the role of SLE CIML NK cells in providing antiviral and anti-tumor responses is warranted. Clinical trial number Not applicable.