To support our results regarding the impaired expression of some activating NK receptors (primarily NKp30) on the PF-NK cells from low-grade PC patients, degranulation assays against K562, a HLA-I negative cell line previously shown to express B7-H6, were performed in the absence or in the presence of the anti-NKp30 blocking mAb. The gene discussed is NCR3; the disease is pachyonychia congenita.