Figure 6.

Natural killer cell cytotoxicity against K562 cells in patients with chronic hepatitis C virus with elevated alanine aminotransferase or persistently normal alanine aminotransferase and in healthy individuals and the effect of in vitro TGF-β1 treatment on the cytotoxicity and natural killer cell receptor expression of freshly isolated natural killer cells. A: Cytotoxicity of NK cells isolated from healthy individuals, HCV carriers with PNALT and chronic HCV with elevated ALT. Cytotoxic activity of NK cells as a percentage of lysed cells is indicated in patients with chronic HCV with elevated ALT or PNALT and in healthy individuals at different effector and target cell ratios. Statistical comparisons were made by using one-way ANOVA with Bonferroni correction. The results were expressed as the mean value ± standard error of the mean (SEM). ^aP ≤ 0.05, significant from patients with chronic HCV with elevated ALT and healthy individuals. B: Cytotoxicity of TGF-β treated NK cells isolated from healthy individuals. Cytotoxic activity of NK cells as a percentage of lysed cells is indicated after TGFβ1 treatment (1 ng/mL) at different effector and target cell ratios. C: Expression of NKG2D, KIR2DL3 and CD160 receptors by TGF-β-treated NK cells. Different NK cell receptor expression by NK cells after TGFβ1 treatment (1 ng/mL). Statistical comparisons were made by one-way ANOVA with Bonferroni correction. The solid bars represent medians; the boxes indicate the interquartile ranges and the lines show the most extreme observations. Differences were considered statistically significant for P values ≤ 0.05. E: Effector cell; T: Target cell; HCV: Hepatitis C virus; ALT: Alanine aminotransferase; PNALT: Persistently normal ALT; NK: Natural killer cell.