PRF1 and Hepatic fibrosis: Following anti-CD3/-CD28 stimulation, the proportion of perforin+ CD8+ T-cells cells from HCV+(F4) individuals with advanced liver fibrosis (mean 23.39%) was significantly greater than HCV+(F0-1) individuals (mean 9.44%) or healthy controls (mean 9.0%) (p = 0.02, ANOVA) (Figure 4).