CXCR3 and influenza: The expression levels of the main surface markers characterizing peripheral Tfh and Th1 cells (i.e. CXCR5, PD-1 and CXCR3) are shown on HCV-specific CD4 T cells in comparison to influenza- (Flu-) specific CD4 T cells ex vivo in a representative HCV-infected, DAA-cured or healthy donor, respectively (Figures 1A–C).