Monocytes in hepatitis C virus (HCV) infection play a critical role in chronic liver inflammation and fibrosis. We studied circulating monocytes and monocyte receptors in patients with HCV infection who were naive to treatment and those who received direct acting antiviral therapy and achieved sustained virological response. CD64+ CCR2+ (M1-like) and CD206+ CD163+ CX3CR1+ (M2-like) monocyte numbers and receptor expression were evaluated by flow cytometry. Higher expression of the monocyte chemokine receptor CCR2 predicted the severity of liver fibrosis, independent of successful treatment and viral clearance (R2 = 0.235, p = 0.002), whereas monocyte CX3CR1 expression was lower in both treated and untreated patients compared with controls (p = 0.011). The expression of the scavenger receptor CD163 was lower in patients with successful treatment (p = 0.005), supporting its role as a marker of treatment response. CD64+ CCR2+ (M1-like) and CD206+ CD163+ CX3CR1+ (M2-like) monocyte numbers were not altered with fibrosis progression or treatment response. Our findings reflect the diverse functions of monocytes in liver inflammation, fibrosis, and therapy. However, HCV clearance did not lead to complete monocyte reconstitution. Targeting monocytes and their chemokine receptors bears therapeutic potential to reduce liver fibrosis and improve disease outcome.
Keywords: CCR2; CX3CR1; HCV; direct acting antiviral therapy; liver fibrosis; monocytes.