Association of Blood NK Cell Phenotype with the Severity of Liver Fibrosis in Patients with Chronic Viral Hepatitis C with Genotype 1 or 3

Abstract

Background: NK cells phenotype and functional state in different genotypes of chronic viral hepatitis C (CVHC), depending on liver fibrosis severity, have not been sufficiently studied, which limits the possibilities for the development of pathology therapy.

Methods: The CVHC diagnosis was based on the EASL recommendations (2018). Clinical examination with liver elastometry was performed in 297 patients with genotype 1 and in 231 patients with genotype 3 CVHC. The blood NK cells phenotype was determined by flow cytometry in 74 individuals with genotype 1 and in 69 individuals with genotype 3 CVHC.

Results: The frequency of METAVIR liver fibrosis stages F3-F4 was 32.5% in individuals with genotype 3, and 20.5% in individuals with genotype 1 CVHC (p = 0.003). In patients with both genotype 1 and genotype 3 CVHC, a decrease in the total number of blood NK cells, CD56^brightCD16⁺ NK cells and an increase in the proportion of CD56^dimCD16⁺ NK cells, CD94⁺ and CD38 ⁺ CD73⁺ NK cells were registered in patients with fibrosis stage F3-F4 by METAVIR in comparison with persons with METAVIR fibrosis stage F0-F1.

Conclusions: In patients with both genotype 1 and genotype 3 CVHC, an imbalance in the ratio between cytokine-producing and cytotoxic NK cells and an increase in the content of NK cells that express inhibitory molecules were determined in patients with severe liver fibrosis.

Keywords: NK cells; liver fibrosis; phenotype; receptor expression; subsets; viral hepatitis C.

Figure 1

Example of tactics for gating NK cells according to panel 1. The color visualizes the distribution of cells expressing the following receptors: CD3—pink, CD16—green, CD56—red. Cells in the E3 gate that do not express CD3, CD16, and CD56 markers are shown in gray.

Figure 2

Subset composition of NK cells in patients with chronic hepatitis C (HCV genotype 1). Horizontal bars depict the group medians and quartile ranges (Me (IQR)) of the quantitative data (% NK cell subsets within total lymphocytes population). Statistical analysis was performed with the Mann–Whitney U test. Description of p value mark (compared to control): *—p value ≤ 0.05, **—p value ≤ 0.01, ***—p value ≤ 0.001. Subfigures show the distribution of NK cell subsets in groups of fibrosi of varying severity and control: (A)—total NK cells (CD3⁻CD56⁺), (B)—CD56^brightCD16⁻, (C)—CD56^brightCD16⁺, (D)—CD56^dimCD16⁻, (E)—CD56^dimCD16⁺, (F)—CD56^brightCD94⁻, (G)—CD56^brightCD94⁺, (H)—CD56^dimCD94⁻, (I)—CD56^dimCD94⁺.

Figure 3

Subset composition of NK cells in patients with chronic hepatitis C (HCV genotype 3). Horizontal bars depict the group medians and quartile ranges (Me (IQR)) of the quantitative data (% NK cell subsets within total lymphocytes population). Statistical analysis was performed with the Mann–Whitney U test. Description of p value mark (compared to control): **—p value ≤ 0.01, ***—p value ≤ 0.001. Subfigures show the distribution of NK cell subsets in groups of fibrosi of varying severity and control: (A)—total NK cells (CD3⁻CD56⁺), (B)—CD56^brightCD16⁻, (C)—CD56^brightCD16⁺, (D)—CD56^dimCD16⁻, (E)—CD56^dimCD16⁺, (F)—CD56^brightCD94⁻, (G)—CD56^brightCD94⁺, (H)—CD56^dimCD94⁻, (I)—CD56^dimCD94⁺.

Figure 4

Dynamics of cytokine-producing and cytotoxic NK cells in CVHC patients with genotypes 1 and 2 depending on liver fibrosis. P_1-4 is comparison reliability of control persons and CVHC patients with METAVIR fibrosis stage F3-F4.