Published online Jan 28, 2016. doi: 10.3748/wjg.v22.i4.1393
Peer-review started: May 12, 2015
First decision: August 26, 2015
Revised: September 11, 2015
Accepted: November 13, 2015
Article in press: November 13, 2015
Published online: January 28, 2016
Processing time: 254 Days and 0.8 Hours
Hepatitis C virus (HCV) has a high propensity to establish chronic infections. Failure of HCV-infected individuals to activate effective antiviral immune responses is at least in part related to HCV-induced impairment of dendritic cells (DCs) that play a central role in activating T cell responses. Although the impact of HCV on DC phenotype and function is likely to be more prominent in the liver, major HCV-induced alterations are detectable in peripheral blood DCs (pbDCs) that represent the most accessible source of DCs. These alterations include numerical reduction, impaired production of inflammatory cytokines and increased production of immunosuppressive IL10. These changes in DCs are relevant to our understanding the immune mechanisms underlying the propensity of HCV to establish persistent infection. Importantly, the non-invasive accessibility of pbDCs renders the analysis of these cells a convenient procedure that can be serially repeated in patient follow-up. Accordingly, the study of pbDCs in HCV-infected patients during conventional treatment with pegylated interferon and ribavirin indicated that restoration of normal plasmacytoid DC count may represent an additional mechanism contributing to the efficacy of the dual therapy. It also identified the pre-treatment levels of plasmacytoid DCs and IL10 as putative predictors of response to therapy. Treatment of chronic HCV infection is changing, as new generation direct-acting antiviral agents will soon be available for use in interferon-free therapeutic strategies. The phenotypic and functional analysis of pbDCs in this novel therapeutic setting will provide a valuable tool for investigating mechanisms underlying treatment efficacy and for identifying predictors of treatment response.
Core tip: Dendritic cells (DCs) are professional antigen-presenting cells that play a primary role in the activation and coordination of primary immune responses. In this review we will illustrate and discuss the emerging understanding of DC impairment occurring in patients with chronic hepatitis C virus (HCV) infection and the impact of therapy on DCs. Particular attention will be paid to HCV-induced alterations of DCs in the peripheral blood, as the non-invasive accessibility of these cells renders their analysis a convenient procedure that can be serially repeated in patient follow-up.