Ειδικές και μη ειδικές ανοσολογικές απαντήσεις έναντι του ιού της ηπατίτιδας β σε νεογνά μητέρων με χρόνια HBV λοίμωξη

Abstract

Background and aim: Vertically transmitted hepatitis B virus (HBV) causes chronic infection in the absence of immunoprophylaxis. It is not clear whether an infected maternal environment can alter the immune responses in uninfected neonates. The present study investigated the HBV antigen specific T-cell responses and the efficacy of the dendritic cell (DC) system in vaccinated neonates of HBsAg(+)/HBeAg(-) mothers. Methods: Blood was collected from HBsAg(+) mothers and their neonates at birth, one and six months old and age-matched controls. HBV-DNA was measured in maternal and neonatal perinatal sera and anti-HBs antibody titers were determined after vaccination course completion. PBMCs were stimulated with HBsAg, HBcAg and mitogen and Th1 and Th2 cytokine production was assessed. PBMCs and cord blood pDCs were cultured with resiquimod and/or rhinovirus (RV) and IFN-- production and pDC phenotype was assessed. She circulating neonatal frequencies of myeloid DC (mDC) and pDCs were determined by flow cytometry. Results: All neonates responded to vaccination. HBV-DNA was detected in 67.7% of the mothers and 40.3% of their infants but was not associated with any neonatal immune responses. Within the subject group HBcAg-stimulation resulted in increased IFN-: production in 30% of the neonates while HBsAg-stimulation resulted in higher IL-2 production but not IL-5, IL-6 and IL-10 production. DC numbers and pDC function were similar between subjects and controls and increased significantly with age. RV infection did not induce pDC maturation until the age of six months independently of maternal HBV status. Conclusion: Almost one third of uninfected neonates develop viral antigen-induced IFN-: production suggesting that they have been exposed to virions or viral derivatives. This encounter, however, does not impair their Th cell responses to vaccination, their DC numbers and pDC function.