Plasma CXCL9 levels in sustained responders versus nonresponders to antiviral therapy. Serial samples were obtained from patients described in Table 2. (A) CXCL9 levels measured 7 days before the start of therapy are lower in those who subsequently achieve an SVR (n = 11) than in those who subsequently have no reduction in HCV RNA during or after antiviral therapy (NR; n = 10). Lines across each column represent the median for each set of measurements. Value of P was calculated by the Mann-Whitney test. (B-C) CXCL9 levels were measured in plasma obtained 7 days before initiation of antiviral therapy, 29 days after initiation of therapy, and 24 weeks after completion of therapy. Results are plotted separately for patients who subsequently achieved an SVR (B) and for patients who did not respond to antiviral therapy (C). Value of P (comparing the levels of CXCL9 at different points during treatment) was calculated by the Friedman test.