KIR2DL1 and Crohn disease: In addition, the KIR2DL1(+)/S1(-)/C2C2 genotype, which is associated with susceptibility to melanoma and lymph node metastasis [51,52], was also observed with a highly significant increase in homozygous KIR2DL3/HLA-C1 in patients with Crohn’s disease, confirming the relevance of the KIR2DL2/KIR2DL3 genes and their interaction with HLA-C and disease.