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.

Excretion patterns of human metapneumovirus and respiratory syncytial virus among young children.

BACKGROUND: As respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) cause serious respiratory tract infections, the routes of transmission of these viruses are important to elucidate. We examined the modes of virus shedding and shedding duration of RSV and hMPV in young children. METHODS: From each child in a group of 44 children (37 RSV-positive, 6 hMPV-positive, and 1 co-infected child), aged between 0.5-38 months, hospitalised at Hvidovre Hospital, Copenhagen, Denmark, one nasopharyngeal aspirate (NPA), saliva, urine, and faeces sample were collected at inclusion and weekly in a three-week period. Sweat and blood samples were obtained at inclusion. The presence of RSV and hMPV RNA was detected using real-time RT-PCR. RESULTS: We detected RSV RNA in 28 saliva specimens, 5 stool samples, and 3 sweat samples. hMPV RNA was detected in one saliva specimen and two sweat samples. Four of the five children shedding RNA in faeces had diarrhoea and children shedding RNA in sweat were either less than five weeks of age or had a chronic lung disease. RSV and hMPV RNA was shed in nasal secretions for a median of 11.5 and 5.0 days respectively (p = 0.001). More than 75% of the family members of the infected children showed to have an upper respiratory tract infection when following up. CONCLUSION: Viral RNA was present in nasal secretions, saliva, sweat, and faeces, but whether or not the virions were infectious and constitute a potential mode of transmission remains to be shown in future studies.