Association of KIR3DS1+HLA-B Bw4[Ile80] combination with susceptibility to tuberculosis in Lur population of Iran

ABSTRACT

Natural killer [NK] cells are the effector cells of innate immunity that respond to infection and tumor. Interactions between killer cell immunoglobulin like receptors [KIR] and human leukocyte antigen [HLA] class I molecules regulate NK cells responses to eliminate infected and transformed cells. To investigate the impact of KIR genes, HLA ligand genes, and KIR-HLA combinations on susceptibility to tuberculosis [TB] in Lur population of Iran. The genomic DNA of 50 patients with TB from Lorestan province of Iran was genotyped for sixteen KIR genes and their five major HLA class I ligands were determined by a polymerase chain reaction-sequence-specific primers [PCR-SSP] assay. The results were compared with those of 200 healthy unrelated Iranian individuals. In Lur population of Iran, a significant decrease in frequency of KIR3DS1 was found in TB patients compared to control group [24% vs. 44.5%, OR=0.394, CI=0.194-0.798, p=0.013]. Also, among the three activating genes that may use HLA class I molecules as their ligands, a significant decrease was shown in frequency of KIR3DS1 with HLA-B Bw4[Ile80] ligand in TB patients compared to control group [4% vs. 23%, OR=0.14, CI=0.033-0.596, p=0.004]. These findings imply a genetic imbalance between activating and inhibitory KIR genes and KIR-HLA combinations in Lur TB patients. Low level of activating KIR3DS1 and its combination with HLA-B Bw4[Ile80] ligand might have an influence on the susceptibility to TB in Lur population of Iran