Comparable functions of plasmacytoid and monocyte-derived dendritic cells in chronic hepatitis C patients and healthy donors

Background/Aims: Dendritic cells (DCs) play a key role in immune responses through antigen presentation and cytokine secretion. Hepatitis C virus (HCV) is able to escape elimination by the immune system and often establishes a chronic infection. To investigate whether DC dysfunction is involved in this process, we have studied monoycte-derived DCs (Mo-DCs) and plasmacytoid DCs (pDCs), which produce large amounts of IFN-alpha, from chronic HCV patients and healthy donors. Methods: We have assessed TNF-alpha and IFN-alpha production by pDCs using intracellular staining after total PBMCs stimulation with unmethylated CG dinucleotides (CpGs). The induction of allogeneic T cell proliferation by immature Mo-DCs was measured using the MLR assay. The up-regulation of maturation markers and the production of TNF-alpha in response to LPS were analyzed using flow cytometry and ELISA, respectively. Results: We have detected comparable frequencies of pDCs producing TNF-alpha and IFN-alpha in both chronic HCV patients and healthy donors and we have found that immature Mo-DCs from both patients and donors similarly induce allogeneic T cell proliferation and mature and secrete TNF-alpha in response to LPS. Conclusions: Our results demonstrate that both pDC and Mo-DCs are not impaired in HCV infected patients. (C) 2004 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.