KIR3DL1 and pachyonychia congenita: Interestingly, in the PF of low-grade PC patients a large fraction of CD56dim NK cells showed features of immature NK cells, characterized by the NKG2A+KIR-CD57-CD16dim phenotype, whereas the percentage of CD56dim NK cells expressing KIR (Figures 3A,B) and LIR-1 (Figure 3A) was increased in the PF of high-grade PC patients.