PD-1 and PD-L1 together constitute the stimulus signaling pathway of adaptive immune response, which has been widely used in the research on the mechanism of tumor immune escape and tumor therapy. At the same time, its signaling pathway has been proved to be closely associated with the immune escape of hepatic echinococcosis. This article reviews the chemical structures of PD-1 and PD-L1, the mechanism of the PD-1/PD-L1 signaling pathway, and the role of the PD-1/PD-L1 signaling pathway in immune escape of hepatic echinococcosis, i.e., the PD-1/PD-L1 signaling pathway is involved in immune escape of hepatic echinococcosis under three theories, so as to explore the immune escape of hepatic echinococcosis from a new perspective and provide a basis and ideas for the diagnosis and treatment of hepatic echinococcosis.

The MAPK signaling pathway can mediate a variety of cytokines to participate in the processes of inflammation, cancer, immune disorder, and neurodegenerative diseases, and it also plays an important role in the development and progression of hepatic echinococcosis. This article reviews the structure and regulation of the MAPK signaling pathway and elaborates on the role of the MAPK signaling pathway in hepatic echinococcosis. It is pointed out that the MAPK signaling pathway can activate both the cyst and the host in hepatic echinococcosis, participate in the development and progression of the disease, and exert an impact on its treatment. Drug therapy targeting the MAPK signaling pathway is expected to become a new strategy for the treatment of hepatic echinococcosis.

Objective To investigate the association between serum macrophage polarization-related factors and liver fibrosis in patients with alveolar echinococcosis (AE). Methods A total of 120 patients with AE who attended Department of Hepatobiliary and Pancreatic Surgery in The Affiliated Hospital of Qinghai University from September 2018 to October 2020 were enrolled as AE group, and 33 healthy controls were enrolled as normal control group. The two groups and the patients with varying degrees of liver fibrosis were compared in terms of the levels of interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and transforming growth factor-β1 (TGF-β1). Comparison of normally distributed continuous data between two groups was made by the independent samples t -test, while comparison of non-normally distributed continuous data was made by the Mann-Whitney U test or Kruskal-Wallis H test. Comparison of categorical data between groups was made by the chi-square test. Univariate and multivariate logistic regression analyses were used to investigate the association between serum macrophage polarization-related factors and liver fibrosis in patients with AE, and the receiver operating characteristic (ROC) curve was used to analyze the value of serological examination in the diagnosis of liver fibrosis in patients with AE. A Spearman correlation analysis was used to analyze the correlation of each index with HAI score and Metavir score. Results Compared with the normal control group, the AE group had significant increases in the serum levels of IL-6 [13.97 (9.64-23.62) pg/mL vs 1.30 (0.35-2.71) pg/mL, Z =-5.980, P < 0.001], TNF-α [2.26 (1.65-4.13) pg/mL vs 1.40 (1.04-2.10) pg/mL, Z =-3.114, P < 0.01], and TGF-β1 [3.64(2.71-5.72) pg/mL vs 2.91(2.20-3.35) pg/mL, Z =-2.594, P < 0.05], and increases in the serum levels of IL-6 (hazard ratio [ HR ]=2.721, 95% confidence interval [ CI ]: 1.730-4.280, P < 0.05) and TNF-α( HR =3.527, 95% CI : 1.158-10.747, P < 0.05) were independent risk factors for the onset of liver fibrosis in AE patients. The ROC curve analysis showed that hydatid IgG combined with the serum levels of IL-6 and TNF-α had a sensitivity of 88.4%, a specificity of 95.8%, and an area under the ROC curve of 0.951(95% CI : 0.937-0.964) in the diagnosis of liver fibrosis, which were significantly higher than those of IL-6, TNF-α, or hydatid IgG alone ( Z =-3.458, -4.011, and 2.379, all P < 0.05). The Spearman analysis showed that the serum levels of IL-6, TNF-α, and TGF-β1 were positively correlated with HAI score ( r =0.560, 0.644, and 0.465, all P < 0.001) and Metavir fibrosis score ( r =0.530, 0.758, and 0.567, all P < 0.001), and the serum level of IL-10 was negatively correlated with HAI score ( r =-0.232, P =0.011) and Metavir fibrosis score ( r =-0.288, P =0.001). Conclusion Macrophage polarization is often observed in patients with hepatic AE, and the levels of the macrophage polarization-related factors IL-6, TNF-α, and TGF-β1 are associated with the development and progression of liver fibrosis, which can provide certain reference information for predicting the onset of liver fibrosis.