CD154 expression reveals the presence of dysfunctional virus-specific CD4+ T cells during chronic HCV infection

Introduction: Virus-specific CD4+ T cells play a major role in HCV infection. Indeed, viral clearance is associated with vigorous and multispecific CD4+ T cell responses while chronic infection is associated with weak or absent HCV specific CD4+ T cell responses. Most of these studies, however, have used functional assays to analyze virus-specific CD4+ T cell responses. Thus, the important question whether virus-specific CD4+ T cells are deleted or maintained but in a dysfunctional state during chronic infection has not been fully resolved. Methods: De novo CD154 (CD40 ligand) expression of CD4+ T cells was anal…