Bijan Ansari-Moghaddam - Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran.
Ali Asghar Kiani - Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran.
Ali Sheikhian - Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran.
Mehdi Birjandi - Department of Epidemiology and Biostatistics, Lorestan University of Medical Sciences, Khorramabad, Iran.
Seyyed Amir Yasin Ahmadi - Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran.
Nazanin Mousavi - Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran.
Hamzeh Ali Torang - Department of Internal Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran.
Farhad Shahsavar - Department of Immunology, Lorestan University of Medical Sciences, Khorramabad, Iran.

Background: 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. Methods: In this case-control study, a total of ۵۰ patients with RA and ۱۰۰ healthy individuals were enrolled. DNA samples were evaluated using PCR with sequence specific Primers (PCR-SSP). Odds ratio (OR) with a ۹۵% confidence interval (CI) were reported. Results: Among the KIR genes examined, KIR۲DLA (p= ۰.۰۲۵۵, OR= ۰.۳۸۹, ۹۵% CI= ۰.۲۱۰-۰.۷۲۲) and KIR۲DS۴-full (p< ۰.۰۰۰۱, OR= ۶.۱۶۳, ۹۵% CI= ۳.۱۷۴-۱۱.۹۶۸) were observed to have a statistically significant correlation with disease susceptibility to RA. As an inhibitory gene, KIR۲DLA was observed to have a protective effect against RA while KIR۲DS۴-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. Conclusions: In this study of RA in the Lur population of Iran, KIR۲DS۴-full was observed to increase susceptibility to RA, while KIR۲DL۵A 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