Particular HLA-KIR permutations were synergistic; e.g., the presence of HLA-C*07 + KIR2DS1 + HLA-C12null versus HLAC*07null + KIR2DS1null + HLA-C12 was associated with COPD, especially among HLA-C1 allotype homozygotes. This evidence concerns the gene HLA-C and chronic obstructive pulmonary disease.