Natural killer cell receptor and HLA-C gene polymorphisms among patients with hepatitis C: a comparison between sustained virological responders and non-responders

Background/Aims Killer cell immunoglobulin-like receptors (KIR) are involved in the activation/inhibition of NK cells through an interaction with HLA class I molecules on target cells. Our study aimed to evaluate the association between KIR gene polymorphisms and the response of patients with CHC to antiviral therapy. Methods We compared the frequency of KIR genes, as well as that of compound KIR/HLA-C genotypes, between groups of patients with CHC who presented a sustained virological response (n=66) and who were non-responders to a combination of pegylated or standard interferon and ribavirin (n=101). KIR and HLA-C genotyping were performed using commercial kits. Results We detected a greater frequency of the KIR2DL5 gene among non-responders to antiviral therapy compared with sustained virological responders (68.3 vs. 40.9%) (P < 0.001). We used multiple logistic regression analysis to determine the association between therapy response and the presence of KIR2DL5, after a control for potentially confounding variables (genotype, alcohol, fibrosis, gender, age, ethnic background and route of HCV infection). The results confirmed the strong association between the presence of KIR2DL5 and the non-response to antiviral treatment (P=0.001). Conclusions Host genetic factors may be associated with a non-response to antiviral therapy. KIR2DL5 is a candidate gene involved in immunomodulation associated with non-response to antiviral therapy.