Volume 141, Issue 4, Pages 1231-1239.e2 (October 2011) Early Changes in Natural Killer Cell Function Indicate Virologic Response to Interferon Therapy for Hepatitis C  Golo Ahlenstiel, Birgit Edlich, Leah J. Hogdal, Yaron Rotman, Mazen Noureddin, Jordan J. Feld, Lauren E. Holz, Rachel H. Titerence, T. Jake Liang, Barbara Rehermann  Gastroenterology  Volume 141, Issue 4, Pages 1231-1239.e2 (October 2011) DOI: 10.1053/j.gastro.2011.06.069 Copyright © 2011 AGA Institute Terms and Conditions

Figure 1 Frequency of NK cells and their subsets during PegIFN/RBV therapy. (A) Gating strategy. (B–D) Frequency of CD56+CD3− NK cells (B) and their CD56bright (C) and CD56dim subsets (D) in PBMCs during PegIFN/RBV therapy. Mean ± standard error of mean are shown (n = 22 patients). (***) P < .001 with repeated measures analysis of variance; *P ≤ .05; **P < .01 with paired Student t test comparing the indicated individual time points to the 0-hour time point. Gastroenterology 2011 141, 1231-1239.e2DOI: (10.1053/j.gastro.2011.06.069) Copyright © 2011 AGA Institute Terms and Conditions

Figure 2 Phenotype of peripheral blood NK cells during PegIFN/RBV therapy. (A–E) MFI of NKG2D (A), NKp30 (B), NKG2C (C), SIGLEC7 (D), and CD69 expression (E) on CD56+CD3− NK cells. (F) Frequency of CXCR3+ cells in the CD56+CD3− NK cell population. Mean ± standard error of mean are shown (n = 22 patients). (***)P < .001 with repeated measures analysis of variance; *P ≤ .05; ***P < .001 with paired Student t test comparing the indicated individual time points to the 0-hour time point. Gastroenterology 2011 141, 1231-1239.e2DOI: (10.1053/j.gastro.2011.06.069) Copyright © 2011 AGA Institute Terms and Conditions

Figure 3 PegIFN/RBV therapy polarizes NK cell function toward increased degranulation and TRAIL production and decreased IFN-γ production. (A–C) Changes in NK cell CD107a (A), TRAIL (B), and IFN-γ expression (C) during PegIFN/RBV therapy. Mean ± standard error of mean of NK cell frequency and MFI are shown for 21, 20, and 22 patients, respectively. Statistical analysis: paired Student t test comparing the indicated individual time points to 0 hours. *P ≤ .05; **P < .01; ***P < .001. Gastroenterology 2011 141, 1231-1239.e2DOI: (10.1053/j.gastro.2011.06.069) Copyright © 2011 AGA Institute Terms and Conditions

Figure 4 Changes in the intrahepatic NK cell subset during the early phase of PegIFN/RBV therapy. (A) The size of the CD16+ NK cell subset, the percentage of TRAIL-expressing NK cells and the TRAIL MFI in a cross-sectional analysis of patients who were randomized to undergo liver biopsies either immediately before (n = 19) or 6 hours after (n = 9) initiation of PegIFN/RBV therapy. Lines indicate the median. (B) Relative serum ALT levels during PegIFN/RBV therapy. Statistical analysis: Wilcoxon matched paired test comparing the individual time points to 0 hours. Mean ± standard error of mean are shown. Gastroenterology 2011 141, 1231-1239.e2DOI: (10.1053/j.gastro.2011.06.069) Copyright © 2011 AGA Institute Terms and Conditions

Figure 5 Degranulation of peripheral blood NK cells correlates to treatment response. (A–B) Correlation between the 24-hour and 48-hour change in the CD107a expression on either all blood NK cells (A) or their CD56dim subset (B) and the first-phase virological response (log decline in HCV titer during the first 48 hours of PegIFN/RBV therapy). (C) Comparison between CD107a expression on CD56dim NK cells of responders (filled circles, n = 10) and nonresponders (open circles, n = 15). Mean ± standard error of mean are shown. The P value was calculated by analysis of variance. Gastroenterology 2011 141, 1231-1239.e2DOI: (10.1053/j.gastro.2011.06.069) Copyright © 2011 AGA Institute Terms and Conditions