Changes in myeloid-derived suppressor cells and cytokine expression during mother-to-child transmission prevention in HBeAg-positive pregnant women with chronic hepatitis B

OBJECTIVE: The objective of this study was to investigate the changes of Myeloid-derived suppressor cells (MDSCs) and cytokines expression during mother-to-child blockade in chronic HBV infected patients. METHOD: This was a single-center, prospective, observational study. From August 2020 to January 2021, 30 pregnant women with chronic hepatitis B (HBV DNA ≥ 5 log10 IU/mL) were enrolled, and their alanine aminotransferase was within the normal range. The period of mother-to-child blockade was divided into T0 (no antiviral treatment), T1 (antiviral treatment for 4 weeks) and T2 (antiviral treatment for 8 weeks). A total of 10mL of peripheral blood was obtained at that three different time points. Flow cytometry was utilized to assess the proportion of MDSCs within the peripheral blood mononuclear cells. Additionally, plasma samples were preserved for the analysis of inflammatory cytokine levels. RESULTS: Thirty were initiated on antiviral therapy during 24-28 weeks of gestation and 19 were monitored for up to 8 weeks after antiviral therapy. The average HBV DNA titer was 8.03 log10 IU/mL at the beginning of antiviral therapy, and decreased to 3.53log10 IU/mL at 8 weeks after antiviral. After antiviral treatment, the percentage of MDSCs significantly decreased from 16.24% (range 2.26-29.12%) at baseline to 9.53% (range 3.89-17.30%) at week 4 and 2.20% (range 0.45-3.95%) at week 8 (repeated-measures ANOVA, P < 0.01). There was no statistically significant correlation between the percentage of MDSCs and the serum HBsAg and HBeAg levels before and after mother-to-children blockade. There was no statistically significant correlation between the percentage of MDSCs (and its subsets) and HBV DNA quantification during follow-up. IL-10 level was positively correlated with the percentage of MDSCs. IFN-γ level was negatively correlated with the percentage of MDSCs (P < 0.0001). There was no statistically significant correlation between IL-6 and, GM-CSF and the percentage of MDSCs. CONCLUSIONS: MDSCs tended to decrease during mother-to-child blockade during pregnancy in HBV chronically infected patients, and monocytic MDSCs was predominant. Inflammatory cytokines IL-6 and GM-CSF were not major contributors to MDSCs levels during pregnancy.