Farhad Shahsavar; Tahereh Mousavi; Alireza Azargoon; Kobra Entezami
Abstract
Background: 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 ...
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Background: 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. Objective: To investigate the impact of KIR genes, HLA ligand genes, and KIR-HLA combinations on susceptibility to tuberculosis (TB) in Lur population of Iran. Methods: 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. Results: 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 Bw4Ile80 ligand in TB patients compared to control group (4% vs. 23%, OR=0.14, CI=0.033-0.596, p=0.004). Conclusion: 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 Bw4Ile80 ligand might have an influence on the susceptibility to TB in Lur population of Iran.
Farhad Shahsavar; Nader Tajik; Kobra-Zinat Entezami; Masoomeh Fallah Radjabzadeh; Behnam Asadifar; Kamran Alimoghaddam; Mohammadreza Ostadali Dahaghi; Arash Jalali; Andisheh Ghashghaie; Ardeshir Ghavamzadeh
Abstract
Background: Interaction between killer cell immunoglobulin-like receptors (KIR) and human leukocyte antigen (HLA) class I molecules is important for regulation of natural killer (NK) cell function. Objective: The aim of this study was to investigate the impact of compound KIR-HLA genotype on susceptibility ...
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Background: Interaction between killer cell immunoglobulin-like receptors (KIR) and human leukocyte antigen (HLA) class I molecules is important for regulation of natural killer (NK) cell function. Objective: The aim of this study was to investigate the impact of compound KIR-HLA genotype on susceptibility to acute leukemia. Methods: Cohorts of Iranian patients with acute myeloid leukemia (AML; n=40) and acute lymphoid leukemia (ALL; n=38) were genotyped for seventeen KIR genes and their three major HLA class I ligand groups (C1, C2, Bw4) by a combined polymerase chain reaction–sequence-specific primers (PCR-SSP) assay. The results were compared with those of 200 healthy control individuals. Results: We found a significantly decreased frequency of KIR2DS3 in AML patients compared to control group (12.5% vs. 38%, odds ratio=0.23, p=0.0018). Also, the KIR3DS1 was less common in AML group than controls (27.5% vs. 44.5%, p=0.0465, not significant after correction). Other analyses including KIR genotypes, distribution and balance of inhibitory and activating KIR+HLA combinations, and co-inheritance of activating KIR genes with inhibitory KIR+HLA pairs were not significantly different between leukemia patients and the control group. However, in AML patients a trend toward less activating and more inhibitory KIR-HLA state was observed. Interestingly, this situation was not found in ALL patients and inhibition enhancement through increase of HLA ligands and inhibi-tory combinations was the main feature in this group. Conclusion: Our findings may suggest a mechanism for escape of leukemic cells from NK cell immunity.
Raja Rajalingam
Abstract
Natural killer (NK) cells are a subset of lymphocytes which play a crucial role in early innate immune response against infection and tumor transformation. Furthermore, they secrete interferon-γ (IFN-γ) and tumor necrosis factor (TNF) prompting adaptive immu-nity. NK cells distinguish the ...
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Natural killer (NK) cells are a subset of lymphocytes which play a crucial role in early innate immune response against infection and tumor transformation. Furthermore, they secrete interferon-γ (IFN-γ) and tumor necrosis factor (TNF) prompting adaptive immu-nity. NK cells distinguish the unhealthy cells from the healthy ones through an array of cell-surface receptors. Human NK cells use inhibitory and activating killer cell Ig-like receptors (KIR) as primary probe to discriminate between healthy and unhealthy cells. The inhibitory KIRs recognize HLA class I molecules and trigger signals that stop NK killing. The activating KIRs are believed to recognize the determinants associated with infections and tumors, and trigger signals that activate NK killing. Therefore, the effec-tor function of a given NK cell depends upon the receptors that it expresses and ligands that it recognizes on the targets. Genes encoding KIRs and HLA ligands are located on different chromosomes, and vary in number and type. The independent segregation of KIR and HLA genes results in variable KIR-HLA combinations in individuals, which may determine the individual’s immunity and susceptibility to disease.
