RUOLO DELL'INTERAZIONE KIRs/HLA NEI PAZIENTI CON INFEZIONE CRONICA DA HBV

Background: The Natural Killer (NK) cells provide a major defense against several infections and their activity is regulated partially through inhibitory and activating killer cell immunoglobulin - like receptors (KIRs) interacting with human leukocyte antigens (HLA) class I molecules. The aim of this study is to assess whether the KIR and HLA repertoire may influence the course of hepatitis B virus (HBV) infection. Methods: Till now, twenty – four patients with chronic HBV infection have been genotyped for KIRs and their HLA ligands, along with non-exposed subjects (HBsAg negative, anti - HBcAb positive with or without anti - HBsAb) as controls. Results: All the KIR haplotypes are represented in the same way. The frequency of KIR2DS2 is higher in patients with chronic HBV infection than in non-exposed subjects (75 % vs 45 % respectively, OR 3.7, p= 0.02) but its interaction with the cognate ligand HLA C1 is not significantly different in the two groups (42% vs 22% respectively, OR 2,58, p= n.s.) . HLA C2 (87% vs 60% respectively, OR 4.67, p= 0.03), HLA Bw4I (58% vs 37% respectively, OR 3.45, p= 0.03) and HLA A 3, 11 (71% vs 10%, OR 21.86, p= < 0.00001) are more frequent in patients with chronic HBV infection than in non-exposed subjects so as the inhibitory KIR3DL2 - HLA A 3,11 (71 % vs 10 % respectively, p < 0,00001, OR 21,86) and KIR2DL2-HLA C1 (58% vs 28% respectively, p= 0.02, OR 3.54) interactions. Conclusions: Our results are consistent with others reported in the recent literature. To sum up, the frequency of inhibitory interactions is higher in patients with chronic HBV infection than in non exposed subjects and the two groups are genetically different. The HLA A 3,11 is strongly represented in the patients group and this result has never been reported in the literature.