Applying next-generation sequencing technology to genotype HLA-I genes (HLA-A, -B, -C) and KIR genes (KIR2DL1, KIR2DL2, KIR2DL3, KIR2DL4, KIR2DL5, KIR2DS1, KIR2DS2, KIR2DS3, KIR2DS4, KIR2DS5, KIR3DL1, KIR3DL3, KIR3DS1, KIR2DP1, KIR3DP1) from 1215 participants in the Diabetes Prevention Trial-Type 1 (DPT-1) and the Diabetes Prevention Trial (TN07), we systematically explored associations of HLA-I–KIR ligand–receptor interactions (LRIs) with disease progression via a Cox regression model. This evidence concerns the gene KIR3DL3 and diabetes mellitus.