Circulating Plasmacytoid Dendritic Cells in Acutely Infected Patients with Hepatitis C Virus Genotype 4 Are Normal in Number and Phenotype

Abstract

The incidence of hepatitis C virus (HCV) genotype 4 infection in Egypt provides a unique opportunity to study the innate immune response to symptomatic acute HCV infection. We investigated whether plasmacytoid dendritic cells (pDCs) are activated as a result of HCV infection. We demonstrate that, even during symptomatic acute infection, circulating pDCs maintained a similar precursor frequency and resting phenotype, compared with pDCs in healthy individuals. Moreover, stimulation with a Toll-like receptor 9 agonist resulted in an intact inflammatory response. These data support the growing consensus that pDCs are not directly activated by HCV and therefore are viable targets for immunotherapy throughout HCV infection.

Indolamine 2,3-dioxygenase expression by monocytes and dendritic cell populations in hepatitis C patients

“…Furthermore, Shiina and Rehermann [25] reported that cell culture-produced HCV inhibited IFNexpression through Toll-like receptor (TLR)-9, indicating a functional impairment. However, in other studies, pDCs from chronic HCV patients seemed phenotypically and functionally not different from those of healthy subjects in vivo [25][26][27], although they occurred in lower numbers [28]. Both mDCs and pDCs also showed a decrease in their cell-surface molecules and co-stimulatory cytokine production as well as their allostimulatory activity [23], which leads to an incapacity to prime T cells and to a much lower anti-viral immune response to HCV.…”