Determination of genotype distribution of inhibitory KIR genes in the population of Southeastern Anatolia region

Killer Cell Immunoglobulin-Like Receptors (KIR) molecules found in the surface of natural killer cells cause the inhibition or activation of cytokine synthesis by interacting directly with HLA class I molecules. KIR gene family is localized in 19q13.4 region in human genome and contists of 16 homologous genes. KIR2DL1-5 and KIR3DL1-3 are the inhibitory KIR genes (iKIR) and especially KIR2DL1, KIR2DL2/L3 and KIR3DL1 not only regulate the NK activity but also direct the training of NK cells. The aim of this study is to determine the gene frequencies of inhibitory KIR genes in Southeastern Anatolia population and to compare the results with the other populations data. Blood samples of totally 200 voluntary subjects from all of the cities of Southeastern Anatolia Region were collected and DNAs were isolated. After DNA quantity/quality control, gene regions were amplified by sequence specific primer-polimerase chain reaction method and the products were seperated and visualized by agarose gel electrophoresis. KIR gene frequencies were calculated by direct counting. Study results indicated that all inhibitory KIR genes are significantly positive (having frequency higher than 50%) in the population. The highest frequency was observed in KIR3DL3 as 99.5%, while the lowest frequency was determined as 56.5% in KIR2DL2 gene. Twenty six (%13) different genotypes were identified among studied 200 individuals. Having hosted to many civilizations throughout the history might be the reason for KIR gene diversity observed in Southeastern Anatolia Region population. Several populations were selected from the literature and the data were compared. Among the selected populations; Russia and Uzbekistan populations were found to be closesest to the Southeastern Anatolia population, while North India was the farest population with respect to the inhibitory KIR gene distribution.