CTLA4 and herpes zoster: While the percentage and CD27-expression of VZV-specific CD4 T cells of the 5 patients with zoster manifestations (labeled in dark red) did not differ from those of patients with lower PFP-scores (Fig. 4B and D), CTLA-4- and Ki67-expression were considerably higher (Fig. 4C and E), with typical dot plots shown in Fig. 4F. Their CTLA-4-MFI was above the cut-off previously established for active VZV-infection [22].