Presence of functional dendritic cells in patients chronically infected with hepatitis C virus.

The absence of expanded numbers of hepatitis C virus (HCV)-reactive CD8(+) T lymphocytes (CTLs) in patients chronically infected with HCV has led to the investigation of dendritic cell (DC) function in this population as a potential cause for this defect. Several studies have shown evidence for impaired monocyte-derived DCs in chronically infected patients. As it is difficult to reconcile these data with the fact that patients with chronic HCV are immune competent, we re-evaluated this finding, carefully assessing phenotypic markers and functional activity of patient DCs as compared with noninfected controls. In contrast to these prior studies, DCs from 13 of 13 chronic HCV patients expressed typical maturation markers. These mature DCs were capable of priming allogeneic T lymphocytes, as well as stimulating influenza-specific memory T cells. This finding is consistent with clinical and immunologic data that the deficit in the patient's immune repertoire is HCV-specific and suggests that refined models are required for understanding the role of DCs in HCV pathogenesis.