IL-15 enhanced the CD158e expression of healthy volunteers (19.8 ± 1.1% vs. 16.3 ± 1.3%, p = 0.028) but not in RA patients (RA 23.1 ± 2.9% vs. 22.3 ± 2.7%, p = 0.382). Here, IL15 is linked to rheumatoid arthritis.