Contribution of KIR

Backgound and aim: There are some common genetic features between celiac disease (CD) and diabetes mellitus type 1 (DM). However, the genetic risk factors have not been fully clarified for CD and the co-occurrence of CD and DM. KIR (killer immunoglobulin-like receptor) genes regulate the cytolitic activity of NK-cells and T lymphocytes. The aim of this study is to evaluate the contribution of KIR genes, KIR ligands, and combinations of KIR/ KIR ligands on the genetic predisposition to CD and co-occurrence of CD and DM. Material and methods: Forty six patients with CD (n = 46), 20 patients with CD+DM (n = 20), and 60 healthy controls (n = 60) were included in this study. KIR genes and KIR ligands were investigated with PCR-SSOP and PCR-SSP in all subjects, respectively. Results: This study showed that while the telomeric KIR genes (2DS5 and 3DS1), and combinations of 3DS1+HLA-BBw4-Thr-and 3DS1+HLA-BBw4-Iso- (p < 0.001, p < 0.001, p < 0.001, and p < 0.001, respectively) were observed more frequently in patients with CD than in controls, the 2DS5, 3DS1 KIR genes, C1 ligand, and combinations of 3DS1+HLA-BBw4-Thr- and 3DS1+HLA-BBw4-Iso- (p = 0.002, p = 0.004, p = 0.036, p < 0.001, and p = 0.007, respectively) were observed more frequently in patients with CD+DM than in controls. Conclusions: The results of this study indicated that some KIR genes, KIR ligands, and KIR/KIR ligand interactions may be responsible for a predisposition to CD and the coexistence of CD and DM. For development of coexisting CD and DM, the 2DS5 and 3DS1 genes, C1 ligand, and combinations of 3DS1+HLA-BBw4Thr- and 3DS1+HLA-BBw4-Iso- were found to be risk factors. Key words: Celiac disease. KIR genes. KIR ligands. KIR/KIR ligand combinations. Type 1 diabetes mellitus.