Defective natural killer cell anti-viral capacity in paediatric HBV infection.

Natural killer (NK) cells exhibit dysregulated effector function in adult chronic hepatitis B virus (HBV) infection (CHB), which may contribute to virus persistence. The role of NK cells in children infected perinatally with HBV is less studied. Access to a unique cohort enabled the cross-sectional evaluation of NK cell frequency, phenotype and function in HBV-infected children relative to uninfected children. We observed a selective defect in NK cell interferon (IFN)-γ production, with conserved cytolytic function, mirroring the functional dichotomy observed in adult infection. Reduced expression of NKp30 on NK cells suggests a role of impaired NK-dendritic cell (DC) cellular interactions as a potential mechanism leading to reduced IFN-γ production. The finding that NK cells are already defective in paediatric CHB, albeit less extensively than in adult CHB, has potential implications for the timing of anti-viral therapy aiming to restore immune control.