Expression of PD-L1 on CD4+CD25+Foxp3+ Regulatory T Cells of Patients with Chronic HBV Infection and Its Correlation with Clinical Parameters.

Abstract Regulatory T cells (Tregs) play a pivotal role in suppressing specific antiviral immune responses during the progression of chronic hepatitis B virus infection (CHB) as well as tumorigenesis. Programmed death-1 ligand-1 (PD-L1) expressed on Tregs can transduce an inhibitory signal into effector T cells through interacting with programmed death-1 (PD-1). However, in CHB patients, the clinical significance of PD-L1 expression on Tregs has not been clearly described. This study investigated the frequency of circulating Tregs and PD-L1 expression on Tregs and analyzed their correlations with clinical parameters. The data show that both the frequency of CD4+CD25+FoxP3+ Tregs and PD-L1 expression on Tregs in the peripheral blood increased significantly in CHB patients when compared with healthy controls. At the same time, it is shown that PD-L1 expression on Tregs was positively correlated with the percentage of Tregs in CHB patients. Moreover, the results demonstrated that both Treg frequency and PD-L...