However, despite the normal phenotype, PD-1+ NK cells demonstrated reduced cytotoxicity and IFN-γ production ex vivo following the direct triggering of NKp30, NKp46, CD16, or short stimulation with target cells, suggesting a role of PD-1 in KS-mediated NK cell exhaustion [133]. This evidence concerns the gene NCR1 and Kaposi's sarcoma.