Effect of Combined HCV Therapy on Natural Killer Cell Activity

Hepatitis C virus (HCV) is a major health problem all over the world with the highest prevalence reported in Egypt. Various treatment regimens have been developed over the last years. Interferon (IFN) based regimen was the standard of care regimen and then the IFN-free therapies were emerged. Host innate immunity through the activity of natural killer (NK) cell is one of the major players in competing infections and tumors, by producing perforin and granzymes that cause cytolysis of target cells, or by the production of various cytokines such as natural interferon gamma. Natural cytotoxicity receptors (NCRs), including Nkp30, Nkp44 and Nkp46, are a group of activating receptors that almost have restricted expression on the surface of NK cells and their density correlates with NK cytotoxicity. The role of these cells is not fully elucidated in patients with chronic HCV infection either treatment-naive or treatment experienced. Therefore, this study aimed to investigate the change that occurs in NK cell activity and cytotoxicity in response to successful elimination of HCV from blood after triple therapy with PEG-IFN-α, ribavirin and sofosbuvir. A total of 56 (50 male: 6 female) HCV patients with mean age of 41.6± 12.1 years were included in this study. They were divided into two groups: treatment naive group (20 patients) and the sustained virologic response (SVR) group (36 patients). All patients were investigated for their NK cell profile, NCRs, perforin and granzyme B expression by flow cytometry. Data was expressed as mean fluorescence intensity (MFI). Results revealed significant increase in MFI of granzyme B (P=0.001) and decrease in MFI of NKp30 (P=0.042) in the SVR group as compared to treatment naïve group. These findings indicated that triple therapy of HCV (IFN, Ribavirin and Sofosbuvir) effected NK activation and cytotoxicity.