NCR1 and systemic lupus erythematosus: IL-15, in contrast to NKp30, down-regulate the NKp46 expression in SLE patients (1785.3±105.1 MFI vs. 2309.0±149.7 MFI, p<0.001) as well as controls (1426.8±106.9 MFI vs. 1440.0±119.4 MFI, p = 0.717).