Increase in CD14+HLA-DR -/low myeloid-derived suppressor cells in hepatocellular carcinoma patients and its impact on prognosis

Abstract

Myeloid-derived suppressor cells (MDSCs) are known as key immune regulators in various human malignancies, and it is reported that CD14(+)HLA-DR(-/low) MDSCs are increased in hepatocellular carcinoma (HCC) patients. However, the host factors that regulate the frequency and the effect on the prognosis of HCC patients are still unclear. We investigated these issues and clarified the relationships between a feature of MDSCs and host factors in HCC patients. We examined the frequency of MDSCs in 123 HCC patients, 30 chronic liver disease patients without HCC, and 13 healthy controls by flow cytometric analysis. The relationships between the clinical features and the frequency of MDSCs were analyzed. In 33 patients who received curative radiofrequency ablation (RFA) therapy, we examined the impact of MDSCs on HCC recurrence. The frequency of MDSCs in HCC patients was significantly increased. It was correlated with tumor progression, but not with the degree of liver fibrosis and inflammation. In terms of serum cytokines, the concentrations of IL-10, IL-13, and vascular endothelial growth factor were significantly correlated with the frequency of MDSCs. In HCC patients who received curative RFA therapy, the frequency of MDSCs after treatment showed various changes and was inversely correlated with recurrence-free survival time. The frequency of MDSCs is correlated with tumor progression, and this frequency after RFA is inversely correlated with the prognosis of HCC patients. Patients with a high frequency of MDSCs after RFA should be closely followed and the inhibition of MDSCs may improve the prognosis of patients.

Fig. 1

a Flow cytometry shows CD14⁺HLA-DR^−/low+ MDSCs. PBMCs from patients and healthy donors were labeled with anti-CD14 and HLA-DR. Three staining examples of HCC patients are shown in the order from a small number (left) to a large number (right). b The increase in CD14⁺HLA-DR^−/low MDSCs/CD14⁺ cells in cryopreserved PBMC correlated with that in fresh PBMC (r ² = 0.52). c Proliferation of PBMCs stimulated by anti-CD3/28 in the presence or absence of MDSCs was measured by ³Hincorporation assay. CD14⁺HLA-DR^−/low MDSCs significantly decreased autologous PBMC proliferation (n = 4; *, p < 0.05). d The frequency of MDSCs was significantly higher in HCC patients than healthy donors (*, p < 0.01). e Overall frequencies of CD14⁺ cells did not differ significantly

Fig. 2

a Scatter plots of MDSC ratio (CD14⁺HLA-DR^−/low MDSCs/CD14⁺ cells) in patients and healthy donors. The frequency of MDSCs was significantly increased in HCC patients compared with that in non-HCC controls. Moreover, the frequency of MDSCs was correlated with tumor progression (stage III and IV: 22.3 % (n = 46) vs. stage I and II: 17.0 % (n = 77); *, p < 0.05). In non-HCC controls, there was no significant difference in the frequency of MDSCs. b, c In non-HCC patients, the frequency of MDSCs did not change depending on the degree of fibrosis or inflammatory activity of the liver according to the Metavir scoring system

Fig. 3

a In 33 HCC patients who received curative RFA therapy, the frequency of MDSCs was significantly decreased after treatment. However, in several patients, the frequencies were increased after treatment (dotted lines) (*, p < 0.05). b Kaplan–Meier curve for recurrence-free survival after RFA therapy. The patients with high frequency of MDSCs (solid line) relapsed