Hepatitis C virus-specific reactivity of CD4+-lymphocytes in children born from HCV-infected women

Background/Aims: T-lymphocyte reactivity against viral antigens may represent the only immunological marker of host contact with a virus. Aim of the present study was to investigate whether vertical exposure to hepatitis C virus (HCV) could activate HCV-specific T-cell responses that may represent a biomarker of previous contact with the virus, and possibly contribute to the low rate of vertical HCV transmission. Methods: We studied 28 children born from chronically HCV-infected mothers. HCV-specific activation and proliferation of CD4+ -lymphocytes and cytokine production were evaluated in cultures of peripheral blood mononuclear cells (PBMCs) stimulated in vitro with HCV-peptides. Results: HCV-specific CD4+-cell reactivity was observed in 20 out of the 28 children (71 %). The proliferation of HCV-specific CD4+ -cells was more frequent and vigorous in children than in their mothers. In children, but not in the mothers, activation of CD4+-cells upon stimulation with HCV-peptides was directly correlated with proliferation. Early upon stimulation with HCV-peptides, lymphocytes from children produced lower levels of IL-10 than lymphocytes from the mothers. Conclusions: Vertical exposure to HCV induces the development of viral-specific CD4+ -cell-mediated immune responses, possibly endowed with protective function against infection, which may contribute to the low rate of vertical HCV transmission. (c) 2005 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.