Background and aims: The role of natural killer (NK) cells in the defense against hepatitis C virus (HCV) infection involve both innate and adaptive immunity. NK cells express a large panel of inhibitory and activating receptors who bind human leukocyte antigen (HLA) class I receptors. Killer cell immunoglobulin-like receptors (KIRs) are the most polymorphic of these receptors being encoded by genes distributed differently in unrelated individuals. The aim of this study was to look at the immune response in chronic HCV patients by assessing NK-KIR genes and their corresponding HLA ligands.
Methods: We genotyped 127 chronically HCV-infected patients and 130 non-infected healthy individuals for both KIR genes and their HLA ligands. The HLA-A, HLA-B, HLA-C genotypes were analyzed using polymerase chain reaction high-resolution typing.
Results: KIR2DL3, KIR2DL5, KIR2DS4 norm, KIR3DL3, KIR2DP1, KIR3DP1 genes were significantly increased in the HCV group compared to healthy individual. Analysis of various HLA haplotypes revealed different HLA alleles associated with increased susceptibility to HCV infection. Thus, HLA A*23:01 was more frequent in the patients' group than in the controls (p=0.030). At the same time HLA B*44:02 and C*04:02 were significantly elevated in HCV-positive patients (p=0.008 and respectively p= 0.007).
Conclusions: These results suggest that the expression of KIR2DL3, KIR2DL5, KIR2DS4 norm, KIR3DL3 genes and the association with HLA alleles such as HLA A*23:01, B*44:02, C*04:02 may increase the patient susceptibility to chronic HCV infection.