Frequency of (A) STAT1+, (B) TRAIL+ and (C) pSTAT1+ NK cells and mean fluorescence intensity (MFI) of these markers per NK cell prior to (pre, day 0) and during (day 1, week 4) of QUAD therapy (filled circles). Immunological read-outs are shown for the first 4 weeks of QUAD therapy, because HCV is already undetectable at week 4, and values of the immunological read-outs plateau with continued weekly PegIFN injections. NK cells of uninfected subjects are shown for comparison (open squares). Statistical analysis: non-parametric paired Wilcoxon-signed-rank test or unpaired Mann-Whitney test. Median and IQR are shown.