en ایمنی شناسی Immunology مقالات اصلی Original Article <strong><em>Background: </em></strong>The pathophysiology underlying the progression and development of autoimmune conditions, such as Rheumatoid Arthritis (RA), is a result of dysregulations of the immune system. Research has explored the genetic alterations present in RA; however, limited studies have examined the role of Killer cell Immunoglobulin-like Receptors (KIR) and Human Leukocyte Antigen (HLA) molecules in RA. Therefore, the aim of this study was to examine KIR genes, their HLA ligands, and KIR-HLA compounds in patients with RA.<br> <br> <em><strong>Methods:</strong></em> In this case-control study, a total of 50 patients with RA and 100 healthy individuals were enrolled. DNA samples were evaluated using PCR with sequence specific Primers (PCR-SSP). Odds ratio (OR) with a 95% confidence interval (CI) were reported.<br> <br> <strong><em>Results: </em></strong>Among the KIR genes examined, KIR2DLA (p= 0.0255, OR= 0.389, 95% CI= 0.210-0.722) and KIR2DS4-full (p< 0.0001, OR= 6.163, 95% CI= 3.174-11.968) were observed to have a statistically significant correlation with disease susceptibility to RA. As an inhibitory gene, KIR2DLA was observed to have a protective effect against RA while KIR2DS4-full as an activating gene, was found to increase risk for RA. No significant associations were found between any of the other KIR genotypes, HLA ligands, or KIR-HLA compounds examined in this study to RA susceptibility.<br> <br> <strong><em>Conclusions:</em></strong> In this study of RA in the Lur population of Iran, KIR2DS4-full was observed to increase susceptibility to RA, while KIR2DL5A was found to act as a protecting factor based on both the cross Table and regression analyses. Further research should focus on repeating this study in additional populations. Rheumatoid Arthritis, NK cells, KIR, HLA 84 94 http://rbmb.net/browse.php?a_code=A-10-638-1&slc_lang=en&sid=1 Bijan Ansari-Moghaddam 100319475328460012748 100319475328460012748 No Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran. Ali Asghar Kiani 100319475328460012749 100319475328460012749 No Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran. Ali Sheikhian 100319475328460012750 100319475328460012750 No Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran. Mehdi Birjandi 100319475328460012751 100319475328460012751 No Department of Epidemiology and Biostatistics, Lorestan University of Medical Sciences, Khorramabad, Iran. Seyyed Amir Yasin Ahmadi 100319475328460012752 100319475328460012752 No Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran. Nazanin Mousavi 100319475328460012753 100319475328460012753 No Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran. Hamzeh Ali Torang 100319475328460012754 100319475328460012754 No Department of Internal Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran. Farhad Shahsavar 100319475328460012755 100319475328460012755 Yes Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran.