Impaired dendritic cell maturation in patients with chronic, but not resolved, hepatitis C virus infection.

Dendritic cells (DCs) are important for the initiation of immune responses to foreign antigens. Their antigen uptake and presentation capacities enable them to prime and activate T cells. Immature DCs capture antigens; however, they must be activated to mature before serving as efficient antigen-presenting cells. The antigen-presenting capacity of DCs can be diminished during viral infection and as a consequence of tumor formation. Chronic infection with hepatitis C virus (HCV) has been shown to affect the allostimulatory function of DCs. In this study, it is demonstrated that monocyte-derived DCs from patients with chronic HCV infection do not respond to maturation stimuli. Instead, they maintain their immature phenotype, reflected by the pattern of cell surface markers and by their continued capacity to uptake antigen. Moreover, their allostimulatory abilities are impaired compared with those of mature DCs derived from healthy donors. To investigate a possible correlation between viral clearance and this DC maturation defect, patients with resolved HCV infection after a course of antiviral therapy were studied. Results demonstrate that DCs from patients who cleared HCV behaved like DCs from healthy donors: in response to maturation stimuli, they decrease antigen uptake, up-regulate expression of appropriate surface markers, and are potent stimulators of allogeneic T cells. (Blood. 2001;97:3171-3176)