Expansion of HLA-G-Expressing Myeloid-Derived Suppressor Cells in Patients with Chronic Hepatitis B Virus Infection

Both human leukocyte antigen-G (HLA-G) and myeloid-derived suppressor cells (MDSCs) was associated with the pathogenesis of infectious diseases. Whether peripheral MDSCs express HLA-G during virus infection remains unknown. We investigated the frequency of HLA-G+ MDSCs and its subsets in patients infected with chronic hepatitis B (CHB). In this study, frequencies of peripheral MDSCs (Lin1-HLA-DR-CD33+CD11b+) and HLA-G expressing subsets from 50 CHB patients and 27 normal controls were analyzed using flow cytometry. Data revealed the median percentage of MDSCs was not significantly different between the CHB patients and controls (0.30% vs. 0.29%; p=0.884). Among MDSCs, similar frequency was observed for CD14+ monocytic MDSC (mMDSCs; 31.25% vs. 23.35%; p=0.063) and CD15+ granulocytic MDSC (gMDSCs; 22.60% vs. 21.55%; p=0.558) between the two groups. However, HLA-G+ MDSCs was significantly increased in CHB patients compared with that of controls (3.30% vs. 0.50%; p<0.001). Furthermore, both HLA-G+ mMDSCs (0.99% vs. 0.00%; p<0.001) and HLAG+ gMDSC (0.78% vs. 0.00%; p<0.001) were also dramatically increased in CHB patients. Particularly, HLA-G+ gMDSC was inversely correlated to the viral DNA loads and significantly increased in HBeAb positive patients. Summary, this work reports for the first time HLA-G+ MDSCs, a new population of peripheral MDSCs, were expanded in CHB patients; however, its clinical relevance yet to be further explored.